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Morito K, Ali H, Kishino S, Tanaka T. Fatty Acid Metabolism in Peroxisomes and Related Disorders. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2024. [PMID: 38811487 DOI: 10.1007/5584_2024_802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2024]
Abstract
One of the functions of peroxisomes is the oxidation of fatty acids (FAs). The importance of this function in our lives is evidenced by the presence of peroxisomal disorders caused by the genetic deletion of proteins involved in these processes. Unlike mitochondrial oxidation, peroxisomal oxidation is not directly linked to ATP production. What is the role of FA oxidation in peroxisomes? Recent studies have revealed that peroxisomes supply the building blocks for lipid synthesis in the endoplasmic reticulum and facilitate intracellular carbon recycling for membrane quality control. Accumulation of very long-chain fatty acids (VLCFAs), which are peroxisomal substrates, is a diagnostic marker in many types of peroxisomal disorders. However, the relationship between VLCFA accumulation and various symptoms of these disorders remains unclear. Recently, we developed a method for solubilizing VLCFAs in aqueous media and found that VLCFA toxicity could be mitigated by oleic acid replenishment. In this chapter, we present the physiological role of peroxisomal FA oxidation and the knowledge obtained from VLCFA-accumulating peroxisome-deficient cells.
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Affiliation(s)
- Katsuya Morito
- Laboratory of Environmental Biochemistry, Division of Biological Sciences, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Hanif Ali
- Graduate School of Technology, Industrial and Social Sciences, Tokushima University, Tokushima, Japan
| | | | - Tamotsu Tanaka
- Graduate School of Technology, Industrial and Social Sciences, Tokushima University, Tokushima, Japan.
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2
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Chen CT, Shao Z, Fu Z. Dysfunctional peroxisomal lipid metabolisms and their ocular manifestations. Front Cell Dev Biol 2022; 10:982564. [PMID: 36187472 PMCID: PMC9524157 DOI: 10.3389/fcell.2022.982564] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 08/17/2022] [Indexed: 11/13/2022] Open
Abstract
Retina is rich in lipids and dyslipidemia causes retinal dysfunction and eye diseases. In retina, lipids are not only important membrane component in cells and organelles but also fuel substrates for energy production. However, our current knowledge of lipid processing in the retina are very limited. Peroxisomes play a critical role in lipid homeostasis and genetic disorders with peroxisomal dysfunction have different types of ocular complications. In this review, we focus on the role of peroxisomes in lipid metabolism, including degradation and detoxification of very-long-chain fatty acids, branched-chain fatty acids, dicarboxylic acids, reactive oxygen/nitrogen species, glyoxylate, and amino acids, as well as biosynthesis of docosahexaenoic acid, plasmalogen and bile acids. We also discuss the potential contributions of peroxisomal pathways to eye health and summarize the reported cases of ocular symptoms in patients with peroxisomal disorders, corresponding to each disrupted peroxisomal pathway. We also review the cross-talk between peroxisomes and other organelles such as lysosomes, endoplasmic reticulum and mitochondria.
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Affiliation(s)
- Chuck T. Chen
- Department of Nutritional Sciences, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Zhuo Shao
- Post-Graduate Medical Education, University of Toronto, Toronto, ON, Canada
- Division of Clinical and Metabolic Genetics, the Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
- The Genetics Program, North York General Hospital, University of Toronto, Toronto, ON, Canada
| | - Zhongjie Fu
- Department of Ophthalmology, Boston Children’s Hospital, Harvard Medical School, Boston, MA, United States
- *Correspondence: Zhongjie Fu,
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3
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Li M, Yang X, Masoudi A, Xiao Q, Li N, Wang N, Chang G, Ren S, Li H, Liu J, Wang H. The regulatory strategy of proteins in the mouse kidney during Babesia microti infection. Exp Parasitol 2022; 235:108232. [DOI: 10.1016/j.exppara.2022.108232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 01/03/2022] [Accepted: 02/10/2022] [Indexed: 11/04/2022]
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4
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Kong G, Lee H, Tran Q, Kim C, Park J, Kwon SH, Kim SH, Park J. Current Knowledge on the Function of α-Methyl Acyl-CoA Racemase in Human Diseases. Front Mol Biosci 2020; 7:153. [PMID: 32760737 PMCID: PMC7372137 DOI: 10.3389/fmolb.2020.00153] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Accepted: 06/18/2020] [Indexed: 01/22/2023] Open
Abstract
Branched chain fatty acids perform very important functions in human diet and drug metabolism. they cannot be metabolized in mitochondria and are instead processed and degraded in peroxisomes due to the presence of methyl groups on the carbon chains. Oxidative degradation pathways for lipids include α- and β-oxidation and several pathways. In all metabolic pathways, α-methyl acyl-CoA racemase (AMACR) plays an essential role by regulating the metabolism of lipids and drugs. AMACR regulates β-oxidation of branched chain lipids in peroxisomes and mitochondria and promotes chiral reversal of 2-methyl acids. AMACR defects cause sensory-motor neuronal and liver abnormalities in humans. These phenotypes are inherited and are caused by mutations in AMACR. In addition, AMACR has been found to be overexpressed in prostate cancer. In addition, the protein levels of AMACR have increased significantly in many types of cancer. Therefore, AMACR may be an important marker in tumors. In this review, a comprehensive overview of AMACR studies in human disease will be described.
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Affiliation(s)
- Gyeyeong Kong
- Department of Pharmacology, College of Medicine, Chungnam National University, Daejeon, South Korea
- Department of Medical Science, Metabolic Syndrome and Cell Signaling Laboratory, Institute for Cancer Research, College of Medicine, Chungnam National University, Daejeon, South Korea
| | - Hyunji Lee
- Department of Pharmacology, College of Medicine, Chungnam National University, Daejeon, South Korea
- Department of Medical Science, Metabolic Syndrome and Cell Signaling Laboratory, Institute for Cancer Research, College of Medicine, Chungnam National University, Daejeon, South Korea
| | - Quangdon Tran
- Department of Pharmacology, College of Medicine, Chungnam National University, Daejeon, South Korea
- Department of Medical Science, Metabolic Syndrome and Cell Signaling Laboratory, Institute for Cancer Research, College of Medicine, Chungnam National University, Daejeon, South Korea
| | - Chaeyeong Kim
- Department of Pharmacology, College of Medicine, Chungnam National University, Daejeon, South Korea
- Department of Medical Science, Metabolic Syndrome and Cell Signaling Laboratory, Institute for Cancer Research, College of Medicine, Chungnam National University, Daejeon, South Korea
| | - Jisoo Park
- Department of Pharmacology, College of Medicine, Chungnam National University, Daejeon, South Korea
- Department of Medical Science, Metabolic Syndrome and Cell Signaling Laboratory, Institute for Cancer Research, College of Medicine, Chungnam National University, Daejeon, South Korea
- Department of Life Science, Hyehwa Liberal Arts College, LINC Plus Project Group, Daejeon University, Daejeon, South Korea
| | - So Hee Kwon
- College of Pharmacy, Yonsei Institute of Pharmaceutical Sciences, Yonsei University, Incheon, South Korea
| | - Seon-Hwan Kim
- Department of Neurosurgery, Institute for Cancer Research, College of Medicine, Chungnam National University, Daejeon, South Korea
| | - Jongsun Park
- Department of Pharmacology, College of Medicine, Chungnam National University, Daejeon, South Korea
- Department of Medical Science, Metabolic Syndrome and Cell Signaling Laboratory, Institute for Cancer Research, College of Medicine, Chungnam National University, Daejeon, South Korea
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Van Veldhoven PP, de Schryver E, Young SG, Zwijsen A, Fransen M, Espeel M, Baes M, Van Ael E. Slc25a17 Gene Trapped Mice: PMP34 Plays a Role in the Peroxisomal Degradation of Phytanic and Pristanic Acid. Front Cell Dev Biol 2020; 8:144. [PMID: 32266253 PMCID: PMC7106852 DOI: 10.3389/fcell.2020.00144] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Accepted: 02/20/2020] [Indexed: 12/04/2022] Open
Abstract
Mice lacking PMP34, a peroxisomal membrane transporter encoded by Slc25a17, did not manifest any obvious phenotype on a Swiss Webster genetic background, even with various treatments designed to unmask impaired peroxisomal functioning. Peroxisomal α- and β-oxidation rates in PMP34 deficient fibroblasts or liver slices were not or only modestly affected and in bile, no abnormal bile acid intermediates were detected. Peroxisomal content of cofactors like CoA, ATP, NAD+, thiamine-pyrophosphate and pyridoxal-phosphate, based on direct or indirect data, appeared normal as were tissue plasmalogen and very long chain fatty acid levels. However, upon dietary phytol administration, the knockout mice displayed hepatomegaly, liver inflammation, and an induction of peroxisomal enzymes. This phenotype was partially mediated by PPARα. Hepatic triacylglycerols and cholesterylesters were elevated and both phytanic acid and pristanic acid accumulated in the liver lipids, in females to higher extent than in males. In addition, pristanic acid degradation products were detected, as wells as the CoA-esters of all these branched fatty acids. Hence, PMP34 is important for the degradation of phytanic/pristanic acid and/or export of their metabolites. Whether this is caused by a shortage of peroxisomal CoA affecting the intraperoxisomal formation of pristanoyl-CoA (and perhaps of phytanoyl-CoA), or the SCPx-catalyzed thiolytic cleavage during pristanic acid β-oxidation, could not be proven in this model, but the phytol-derived acyl-CoA profile is compatible with the latter possibility. On the other hand, the normal functioning of other peroxisomal pathways, and especially bile acid formation, seems to exclude severe transport problems or a shortage of CoA, and other cofactors like FAD, NAD(P)+, TPP. Based on our findings, PMP34 deficiency in humans is unlikely to be a life threatening condition but could cause elevated phytanic/pristanic acid levels in older adults.
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Affiliation(s)
| | - Evelyn de Schryver
- LIPIT, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Stephen G. Young
- Departments of Medicine and Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
| | - An Zwijsen
- Laboratory of Developmental Signaling, Department Human Genetics, VIB-KU Leuven, Leuven, Belgium
| | - Marc Fransen
- LIPIT, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Marc Espeel
- Department of Anatomy, Embryology, Histology and Medical Physics, Ghent University, Ghent, Belgium
| | - Myriam Baes
- Laboratory of Cell Metabolism, Faculty of Pharmaceutical Sciences, KU Leuven, Leuven, Belgium
| | - Elke Van Ael
- LIPIT, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
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6
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Petrova YD, Wadda K, Nathubhai A, Yevglevskis M, Mitchell PJ, James TD, Threadgill MD, Woodman TJ, Lloyd MD. Identification of novel small-molecule inhibitors of α-methylacyl-CoA racemase (AMACR; P504S) and structure-activity relationships. Bioorg Chem 2019; 92:103264. [PMID: 31536955 DOI: 10.1016/j.bioorg.2019.103264] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Revised: 09/04/2019] [Accepted: 09/05/2019] [Indexed: 12/24/2022]
Abstract
α-Methylacyl-CoA racemase (AMACR; P504S; EC 5.1.99.4) catalyses epimerization of 2-methylacyl-CoAs and is important for the degradation of branched-chain fatty acids and the pharmacological activation of ibuprofen and related drugs. It is also a novel drug target for prostate and other cancers. However, development of AMACR as a drug target has been hampered by the difficulties in assaying enzyme activity. Consequently, reported inhibitors have been rationally designed acyl-CoA esters, which are delivered as their carboxylate prodrugs. The novel colorimetric assay for AMACR based on the elimination of 2,4-dinitrophenolate was developed for high-throughput screening and 20,387 'drug-like compounds' were screened, with a throughput of 768 compounds assayed per day. Pyrazoloquinolines and pyrazolopyrimidines were identified as novel scaffolds and investigated as AMACR inhibitors. The most potent inhibitors have IC50 values of ~2 µM. The pyrazoloquinoline inhibitor 10a displayed uncompetitive inhibition, whilst 10j displayed mixed competitive inhibition. The pyrazolopyrimidine inhibitor 11k displayed uncompetitive inhibition. This is the first report of the identification of specific drug-like small-molecule AMACR inhibitors by high-throughput screening. Pyrazoloquinolines and pyrazolopyrimidines may also be useful as inhibitors of other CoA-utilizing enzymes.
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Affiliation(s)
- Yoana D Petrova
- Drug & Target Discovery, Department of Pharmacy & Pharmacology, University of Bath, Claverton Down, Bath BA2 7AY, UK
| | - Katty Wadda
- Drug & Target Discovery, Department of Pharmacy & Pharmacology, University of Bath, Claverton Down, Bath BA2 7AY, UK; Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, UK
| | - Amit Nathubhai
- Drug & Target Discovery, Department of Pharmacy & Pharmacology, University of Bath, Claverton Down, Bath BA2 7AY, UK; School of Pharmacy and Pharmaceutical Sciences, Sciences Complex, City Campus, Dale Building, Room 121, Sunderland SR1 3SD, UK(1)
| | - Maksims Yevglevskis
- Drug & Target Discovery, Department of Pharmacy & Pharmacology, University of Bath, Claverton Down, Bath BA2 7AY, UK
| | - Paul J Mitchell
- Drug & Target Discovery, Department of Pharmacy & Pharmacology, University of Bath, Claverton Down, Bath BA2 7AY, UK
| | - Tony D James
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, UK
| | - Michael D Threadgill
- Drug & Target Discovery, Department of Pharmacy & Pharmacology, University of Bath, Claverton Down, Bath BA2 7AY, UK
| | - Timothy J Woodman
- Drug & Target Discovery, Department of Pharmacy & Pharmacology, University of Bath, Claverton Down, Bath BA2 7AY, UK
| | - Matthew D Lloyd
- Drug & Target Discovery, Department of Pharmacy & Pharmacology, University of Bath, Claverton Down, Bath BA2 7AY, UK.
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Yevglevskis M, Nathubhai A, Wadda K, Lee GL, Al-Rawi S, Jiao T, Mitchell PJ, James TD, Threadgill MD, Woodman TJ, Lloyd MD. Novel 2-arylthiopropanoyl-CoA inhibitors of α-methylacyl-CoA racemase 1A (AMACR; P504S) as potential anti-prostate cancer agents. Bioorg Chem 2019; 92:103263. [PMID: 31536953 DOI: 10.1016/j.bioorg.2019.103263] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Revised: 09/04/2019] [Accepted: 09/05/2019] [Indexed: 10/26/2022]
Abstract
α-Methylacyl-CoA racemase (AMACR; P504S) catalyses an essential step in the degradation of branched-chain fatty acids and the activation of ibuprofen and related drugs. AMACR has gained much attention as a drug target and biomarker, since it is found at elevated levels in prostate cancer and several other cancers. Herein, we report the synthesis of 2-(phenylthio)propanoyl-CoA derivatives which provided potent AMACR inhibitory activity (IC50 = 22-100 nM), as measured by the AMACR colorimetric activity assay. Inhibitor potency positively correlates with calculated logP, although 2-(3-benzyloxyphenylthio)propanoyl-CoA and 2-(4-(2-methylpropoxy)phenylthio)propanoyl-CoA were more potent than predicted by this parameter. Subsequently, carboxylic acid precursors were evaluated against androgen-dependent LnCaP prostate cancer cells and androgen-independent Du145 and PC3 prostate cancer cells using the MTS assay. All tested precursor acids showed inhibitory activity against LnCaP, Du145 and PC3 cells at 500 µM, but lacked activity at 100 µM. This is the first extensive structure-activity relationship study on the influence of side-chain interactions on the potency of novel rationally designed AMACR inhibitors.
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Affiliation(s)
- Maksims Yevglevskis
- Drug & Target Discovery, Department of Pharmacy & Pharmacology, University of Bath, Claverton Down, Bath BA2 7AY, UK
| | - Amit Nathubhai
- Drug & Target Discovery, Department of Pharmacy & Pharmacology, University of Bath, Claverton Down, Bath BA2 7AY, UK; University of Sunderland, School of Pharmacy and Pharmaceutical Sciences, Sciences Complex, Sunderland SR1 3SD, UK(1)
| | - Katty Wadda
- Drug & Target Discovery, Department of Pharmacy & Pharmacology, University of Bath, Claverton Down, Bath BA2 7AY, UK; Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, UK
| | - Guat L Lee
- Drug & Target Discovery, Department of Pharmacy & Pharmacology, University of Bath, Claverton Down, Bath BA2 7AY, UK
| | - Suzanne Al-Rawi
- Drug & Target Discovery, Department of Pharmacy & Pharmacology, University of Bath, Claverton Down, Bath BA2 7AY, UK
| | - Tingying Jiao
- Drug & Target Discovery, Department of Pharmacy & Pharmacology, University of Bath, Claverton Down, Bath BA2 7AY, UK; School of Pharmaceutical Sciences, Shandong University, Jinan, People's Republic of China
| | - Paul J Mitchell
- Drug & Target Discovery, Department of Pharmacy & Pharmacology, University of Bath, Claverton Down, Bath BA2 7AY, UK
| | - Tony D James
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, UK
| | - Michael D Threadgill
- Drug & Target Discovery, Department of Pharmacy & Pharmacology, University of Bath, Claverton Down, Bath BA2 7AY, UK
| | - Timothy J Woodman
- Drug & Target Discovery, Department of Pharmacy & Pharmacology, University of Bath, Claverton Down, Bath BA2 7AY, UK
| | - Matthew D Lloyd
- Drug & Target Discovery, Department of Pharmacy & Pharmacology, University of Bath, Claverton Down, Bath BA2 7AY, UK.
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8
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Yevglevskis M, Lee GL, Nathubhai A, Petrova YD, James TD, Threadgill MD, Woodman TJ, Lloyd MD. Structure-activity relationships of rationally designed AMACR 1A inhibitors. Bioorg Chem 2018; 79:145-154. [PMID: 29751320 DOI: 10.1016/j.bioorg.2018.04.024] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Revised: 04/20/2018] [Accepted: 04/24/2018] [Indexed: 12/12/2022]
Abstract
α-Methylacyl-CoA racemase (AMACR; P504S) is a promising novel drug target for prostate and other cancers. Assaying enzyme activity is difficult due to the reversibility of the 'racemisation' reaction and the difficulties in the separation of epimeric products; consequently few inhibitors have been described and no structure-activity relationship study has been performed. This paper describes the first structure-activity relationship study, in which a series of 23 known and potential rational AMACR inhibitors were evaluated. AMACR was potently inhibited (IC50 = 400-750 nM) by ibuprofenoyl-CoA and derivatives. Potency was positively correlated with inhibitor lipophilicity. AMACR was also inhibited by straight-chain and branched-chain acyl-CoA esters, with potency positively correlating with inhibitor lipophilicity. 2-Methyldecanoyl-CoAs were ca. 3-fold more potent inhibitors than decanoyl-CoA, demonstrating the importance of the 2-methyl group for effective inhibition. Elimination substrates and compounds with modified acyl-CoA cores were also investigated, and shown to be potent inhibitors. These results are the first to demonstrate structure-activity relationships of rational AMACR inhibitors and that potency can be predicted by acyl-CoA lipophilicity. The study also demonstrates the utility of the colorimetric assay for thorough inhibitor characterisation.
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Affiliation(s)
- Maksims Yevglevskis
- Drug & Target Discovery, Department of Pharmacy & Pharmacology, University of Bath, Claverton Down, Bath BA2 7AY, UK
| | - Guat L Lee
- Drug & Target Discovery, Department of Pharmacy & Pharmacology, University of Bath, Claverton Down, Bath BA2 7AY, UK
| | - Amit Nathubhai
- Drug & Target Discovery, Department of Pharmacy & Pharmacology, University of Bath, Claverton Down, Bath BA2 7AY, UK
| | - Yoana D Petrova
- Drug & Target Discovery, Department of Pharmacy & Pharmacology, University of Bath, Claverton Down, Bath BA2 7AY, UK
| | - Tony D James
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, UK
| | - Michael D Threadgill
- Drug & Target Discovery, Department of Pharmacy & Pharmacology, University of Bath, Claverton Down, Bath BA2 7AY, UK
| | - Timothy J Woodman
- Drug & Target Discovery, Department of Pharmacy & Pharmacology, University of Bath, Claverton Down, Bath BA2 7AY, UK
| | - Matthew D Lloyd
- Drug & Target Discovery, Department of Pharmacy & Pharmacology, University of Bath, Claverton Down, Bath BA2 7AY, UK.
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Mezzar S, De Schryver E, Asselberghs S, Meyhi E, Morvay PL, Baes M, Van Veldhoven PP. Phytol-induced pathology in 2-hydroxyacyl-CoA lyase (HACL1) deficient mice. Evidence for a second non-HACL1-related lyase. Biochim Biophys Acta Mol Cell Biol Lipids 2017. [PMID: 28629946 DOI: 10.1016/j.bbalip.2017.06.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
2-Hydroxyacyl-CoA lyase (HACL1) is a key enzyme of the peroxisomal α-oxidation of phytanic acid. To better understand its role in health and disease, a mouse model lacking HACL1 was investigated. Under normal conditions, these mice did not display a particular phenotype. However, upon dietary administration of phytol, phytanic acid accumulated in tissues, mainly in liver and serum of KO mice. As a consequence of phytanic acid (or a metabolite) toxicity, KO mice displayed a significant weight loss, absence of abdominal white adipose tissue, enlarged and mottled liver and reduced hepatic glycogen and triglycerides. In addition, hepatic PPARα was activated. The central nervous system of the phytol-treated mice was apparently not affected. In addition, 2OH-FA did not accumulate in the central nervous system of HACL1 deficient mice, likely due to the presence in the endoplasmic reticulum of an alternate HACL1-unrelated lyase. The latter may serve as a backup system in certain tissues and account for the formation of pristanic acid in the phytol-fed KO mice. As the degradation of pristanic acid is also impaired, both phytanoyl- and pristanoyl-CoA levels are increased in liver, and the ω-oxidized metabolites are excreted in urine. In conclusion, HACL1 deficiency is not associated with a severe phenotype, but in combination with phytanic acid intake, the normal situation in man, it might present with phytanic acid elevation and resemble a Refsum like disorder.
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Affiliation(s)
- Serena Mezzar
- LIPIT, Department of Cellular and Molecular Medicine, KU Leuven, Belgium
| | - Evelyn De Schryver
- LIPIT, Department of Cellular and Molecular Medicine, KU Leuven, Belgium
| | - Stanny Asselberghs
- LIPIT, Department of Cellular and Molecular Medicine, KU Leuven, Belgium
| | - Els Meyhi
- LIPIT, Department of Cellular and Molecular Medicine, KU Leuven, Belgium
| | - Petruta L Morvay
- LIPIT, Department of Cellular and Molecular Medicine, KU Leuven, Belgium
| | - Myriam Baes
- Laboratory for Cell Metabolism, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Belgium
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10
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Vaz FM, Ferdinandusse S. Bile acid analysis in human disorders of bile acid biosynthesis. Mol Aspects Med 2017; 56:10-24. [PMID: 28322867 DOI: 10.1016/j.mam.2017.03.003] [Citation(s) in RCA: 87] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 03/11/2017] [Accepted: 03/16/2017] [Indexed: 01/17/2023]
Abstract
Bile acids facilitate the absorption of lipids in the gut, but are also needed to maintain cholesterol homeostasis, induce bile flow, excrete toxic substances and regulate energy metabolism by acting as signaling molecules. Bile acid biosynthesis is a complex process distributed across many cellular organelles and requires at least 17 enzymes in addition to different metabolite transport proteins to synthesize the two primary bile acids, cholic acid and chenodeoxycholic acid. Disorders of bile acid synthesis can present from the neonatal period to adulthood and have very diverse clinical symptoms ranging from cholestatic liver disease to neuropsychiatric symptoms and spastic paraplegias. This review describes the different bile acid synthesis pathways followed by a summary of the current knowledge on hereditary disorders of human bile acid biosynthesis with a special focus on diagnostic bile acid profiling using mass spectrometry.
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Affiliation(s)
- Frédéric M Vaz
- Department of Clinical Chemistry and Pediatrics, Laboratory Genetic Metabolic Diseases, Academic Medical Center, Amsterdam, The Netherlands.
| | - Sacha Ferdinandusse
- Department of Clinical Chemistry and Pediatrics, Laboratory Genetic Metabolic Diseases, Academic Medical Center, Amsterdam, The Netherlands
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11
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Yevglevskis M, Lee GL, Nathubhai A, Petrova YD, James TD, Threadgill MD, Woodman TJ, Lloyd MD. A novel colorimetric assay for α-methylacyl-CoA racemase 1A (AMACR; P504S) utilizing the elimination of 2,4-dinitrophenolate. Chem Commun (Camb) 2017; 53:5087-5090. [DOI: 10.1039/c7cc00476a] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A versatile continuous colorimetric assay for AMACR is reported.
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Affiliation(s)
- Maksims Yevglevskis
- Drug & Target Development
- Department of Pharmacy & Pharmacology
- University of Bath
- Bath BA2 7AY
- UK
| | - Guat L. Lee
- Drug & Target Development
- Department of Pharmacy & Pharmacology
- University of Bath
- Bath BA2 7AY
- UK
| | - Amit Nathubhai
- Drug & Target Development
- Department of Pharmacy & Pharmacology
- University of Bath
- Bath BA2 7AY
- UK
| | - Yoana D. Petrova
- Drug & Target Development
- Department of Pharmacy & Pharmacology
- University of Bath
- Bath BA2 7AY
- UK
| | - Tony D. James
- Department of Chemistry
- University of Bath
- Bath BA2 7AY
- UK
| | - Michael D. Threadgill
- Drug & Target Development
- Department of Pharmacy & Pharmacology
- University of Bath
- Bath BA2 7AY
- UK
| | - Timothy J. Woodman
- Drug & Target Development
- Department of Pharmacy & Pharmacology
- University of Bath
- Bath BA2 7AY
- UK
| | - Matthew D. Lloyd
- Drug & Target Development
- Department of Pharmacy & Pharmacology
- University of Bath
- Bath BA2 7AY
- UK
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12
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Wanders RJA, Waterham HR, Ferdinandusse S. Metabolic Interplay between Peroxisomes and Other Subcellular Organelles Including Mitochondria and the Endoplasmic Reticulum. Front Cell Dev Biol 2016; 3:83. [PMID: 26858947 PMCID: PMC4729952 DOI: 10.3389/fcell.2015.00083] [Citation(s) in RCA: 195] [Impact Index Per Article: 24.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Accepted: 12/10/2015] [Indexed: 01/02/2023] Open
Abstract
Peroxisomes are unique subcellular organelles which play an indispensable role in several key metabolic pathways which include: (1.) etherphospholipid biosynthesis; (2.) fatty acid beta-oxidation; (3.) bile acid synthesis; (4.) docosahexaenoic acid (DHA) synthesis; (5.) fatty acid alpha-oxidation; (6.) glyoxylate metabolism; (7.) amino acid degradation, and (8.) ROS/RNS metabolism. The importance of peroxisomes for human health and development is exemplified by the existence of a large number of inborn errors of peroxisome metabolism in which there is an impairment in one or more of the metabolic functions of peroxisomes. Although the clinical signs and symptoms of affected patients differ depending upon the enzyme which is deficient and the extent of the deficiency, the disorders involved are usually (very) severe diseases with neurological dysfunction and early death in many of them. With respect to the role of peroxisomes in metabolism it is clear that peroxisomes are dependent on the functional interplay with other subcellular organelles to sustain their role in metabolism. Indeed, whereas mitochondria can oxidize fatty acids all the way to CO2 and H2O, peroxisomes are only able to chain-shorten fatty acids and the end products of peroxisomal beta-oxidation need to be shuttled to mitochondria for full oxidation to CO2 and H2O. Furthermore, NADH is generated during beta-oxidation in peroxisomes and beta-oxidation can only continue if peroxisomes are equipped with a mechanism to reoxidize NADH back to NAD+, which is now known to be mediated by specific NAD(H)-redox shuttles. In this paper we describe the current state of knowledge about the functional interplay between peroxisomes and other subcellular compartments notably the mitochondria and endoplasmic reticulum for each of the metabolic pathways in which peroxisomes are involved.
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Affiliation(s)
- Ronald J A Wanders
- Laboratory Genetic Metabolic Diseases, Laboratory Division, Departments of Paediatrics and Clinical Chemistry, Academic Medical Center, Emma Children's Hospital, University of Amsterdam Amsterdam, Netherlands
| | - Hans R Waterham
- Laboratory Genetic Metabolic Diseases, Laboratory Division, Departments of Paediatrics and Clinical Chemistry, Academic Medical Center, Emma Children's Hospital, University of Amsterdam Amsterdam, Netherlands
| | - Sacha Ferdinandusse
- Laboratory Genetic Metabolic Diseases, Laboratory Division, Departments of Paediatrics and Clinical Chemistry, Academic Medical Center, Emma Children's Hospital, University of Amsterdam Amsterdam, Netherlands
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Yevglevskis M, Lee GL, Sun J, Zhou S, Sun X, Kociok-Köhn G, James TD, Woodman TJ, Lloyd MD. A study on the AMACR catalysed elimination reaction and its application to inhibitor testing. Org Biomol Chem 2016; 14:612-622. [PMID: 26537174 PMCID: PMC4718014 DOI: 10.1039/c5ob01541c] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2015] [Accepted: 10/27/2015] [Indexed: 12/15/2022]
Abstract
α-Methylacyl-CoA racemase (AMACR; P504S) catalyses a key step in the degradation of branched-chain fatty acids and is important for the pharmacological activation of Ibuprofen and related drugs. Levels of AMACR are increased in prostate and other cancers, and it is a drug target. Development of AMACR as a drug target is hampered by lack of a convenient assay. AMACR irreversibly catalyses the elimination of HF from 3-fluoro-2-methylacyl-CoA substrates, and this reaction was investigated for use as an assay. Several known inhibitors and alternative substrates reduced conversion of 3-fluoro-2-methyldecanoyl-CoA by AMACR, as determined by (1)H NMR. The greatest reduction of activity was observed with known potent inhibitors. A series of novel acyl-CoA esters with aromatic side chains were synthesised for testing as chromophoric substrates. These acyl-CoA esters were converted to unsaturated products by AMACR, but their use was limited by non-enzymatic elimination. Fluoride sensors were also investigated as a method of quantifying released fluoride and thus AMACR activity. These sensors generally suffered from high background signal and lacked reproducibility under the assay conditions. In summary, the elimination reaction can be used to characterise inhibitors, but it was not possible to develop a convenient colorimetric or fluorescent assay using 3-fluoro-2-methylacyl-CoA substrates.
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Affiliation(s)
- Maksims Yevglevskis
- Medicinal Chemistry , Department of Pharmacy & Pharmacology , University of Bath , Claverton Down , Bath BA2 7AY , UK . ; Fax: +44 (0)1225 386114
| | - Guat L. Lee
- Medicinal Chemistry , Department of Pharmacy & Pharmacology , University of Bath , Claverton Down , Bath BA2 7AY , UK . ; Fax: +44 (0)1225 386114
| | - Jenny Sun
- Medicinal Chemistry , Department of Pharmacy & Pharmacology , University of Bath , Claverton Down , Bath BA2 7AY , UK . ; Fax: +44 (0)1225 386114
- Department of Pharmacy , Shandong University , People's Republic of China
| | - Shiyi Zhou
- Medicinal Chemistry , Department of Pharmacy & Pharmacology , University of Bath , Claverton Down , Bath BA2 7AY , UK . ; Fax: +44 (0)1225 386114
- Department of Pharmacy , Shandong University , People's Republic of China
| | - Xiaolong Sun
- Department of Chemistry , University of Bath , Claverton Down , Bath BA2 7AY , UK
| | - Gabriele Kociok-Köhn
- Department of Chemistry , University of Bath , Claverton Down , Bath BA2 7AY , UK
| | - Tony D. James
- Department of Chemistry , University of Bath , Claverton Down , Bath BA2 7AY , UK
| | - Timothy J. Woodman
- Medicinal Chemistry , Department of Pharmacy & Pharmacology , University of Bath , Claverton Down , Bath BA2 7AY , UK . ; Fax: +44 (0)1225 386114
| | - Matthew D. Lloyd
- Medicinal Chemistry , Department of Pharmacy & Pharmacology , University of Bath , Claverton Down , Bath BA2 7AY , UK . ; Fax: +44 (0)1225 386114
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14
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Tillander V, Arvidsson Nordström E, Reilly J, Strozyk M, Van Veldhoven PP, Hunt MC, Alexson SEH. Acyl-CoA thioesterase 9 (ACOT9) in mouse may provide a novel link between fatty acid and amino acid metabolism in mitochondria. Cell Mol Life Sci 2014; 71:933-48. [PMID: 23864032 PMCID: PMC11114068 DOI: 10.1007/s00018-013-1422-1] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2013] [Revised: 06/13/2013] [Accepted: 07/04/2013] [Indexed: 02/03/2023]
Abstract
Acyl-CoA thioesterase (ACOT) activities are found in prokaryotes and in several compartments of eukaryotes where they hydrolyze a wide range of acyl-CoA substrates and thereby regulate intracellular acyl-CoA/CoA/fatty acid levels. ACOT9 is a mitochondrial ACOT with homologous genes found from bacteria to humans and in this study we have carried out an in-depth kinetic characterization of ACOT9 to determine its possible physiological function. ACOT9 showed unusual kinetic properties with activity peaks for short-, medium-, and saturated long-chain acyl-CoAs with highest V max with propionyl-CoA and (iso) butyryl-CoA while K cat/K m was highest with saturated long-chain acyl-CoAs. Further characterization of the short-chain acyl-CoA activity revealed that ACOT9 also hydrolyzes a number of short-chain acyl-CoAs and short-chain methyl-branched CoA esters that suggest a role for ACOT9 in regulation also of amino acid metabolism. In spite of markedly different K ms, ACOT9 can hydrolyze both short- and long-chain acyl-CoAs simultaneously, indicating that ACOT9 may provide a novel regulatory link between fatty acid and amino acid metabolism in mitochondria. Based on similar acyl-CoA chain-length specificities of recombinant ACOT9 and ACOT activity in mouse brown adipose tissue and kidney mitochondria, we conclude that ACOT9 is the major mitochondrial ACOT hydrolyzing saturated C2-C20-CoA in these tissues. Finally, ACOT9 activity is strongly regulated by NADH and CoA, suggesting that mitochondrial metabolic state regulates the function of ACOT9.
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Affiliation(s)
- Veronika Tillander
- Department of Laboratory Medicine, Division of Clinical Chemistry, Karolinska Institutet, C1-74, Karolinska University Hospital, SE-141 86 Stockholm, Sweden
| | - Elisabet Arvidsson Nordström
- Department of Laboratory Medicine, Division of Clinical Chemistry, Karolinska Institutet, C1-74, Karolinska University Hospital, SE-141 86 Stockholm, Sweden
| | - Jenny Reilly
- Department of Laboratory Medicine, Division of Clinical Chemistry, Karolinska Institutet, C1-74, Karolinska University Hospital, SE-141 86 Stockholm, Sweden
| | - Malgorzata Strozyk
- Department of Laboratory Medicine, Division of Clinical Chemistry, Karolinska Institutet, C1-74, Karolinska University Hospital, SE-141 86 Stockholm, Sweden
| | - Paul P. Van Veldhoven
- Department of Cellular and Molecular Medicine, LIPIT, Campus Gasthuisberg, Katholieke Universiteit Leuven, Herestraat, Leuven, Belgium
| | - Mary C. Hunt
- Dublin Institute of Technology, School of Biological Sciences, Kevin Street, Dublin 8, Ireland
| | - Stefan E. H. Alexson
- Department of Laboratory Medicine, Division of Clinical Chemistry, Karolinska Institutet, C1-74, Karolinska University Hospital, SE-141 86 Stockholm, Sweden
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15
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Van der Eecken V, Clippe A, Dekoninck S, Goemaere J, Walbrecq G, Van Veldhoven PP, Knoops B. Abolition of peroxiredoxin-5 mitochondrial targeting during canid evolution. PLoS One 2013; 8:e72844. [PMID: 24023783 PMCID: PMC3759418 DOI: 10.1371/journal.pone.0072844] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2013] [Accepted: 07/16/2013] [Indexed: 11/19/2022] Open
Abstract
In human, the subcellular targeting of peroxiredoxin-5 (PRDX5), a thioredoxin peroxidase, is dependent on the use of multiple alternative transcription start sites and two alternative in-frame translation initiation sites, which determine whether or not the region encoding a mitochondrial targeting sequence (MTS) is translated. In the present study, the abolition of PRDX5 mitochondrial targeting in dog is highlighted and the molecular mechanism underlying the loss of mitochondrial PRDX5 during evolution is examined. Here, we show that the absence of mitochondrial PRDX5 is generalized among the extant canids and that the first events leading to PRDX5 MTS abolition in canids involve a mutation in the more 5′ translation initiation codon as well as the appearance of a STOP codon. Furthermore, we found that PRDX5 MTS functionality is maintained in giant panda and northern elephant seal, which are phylogenetically closely related to canids. Also, the functional consequences of the restoration of mitochondrial PRDX5 in dog Madin-Darby canine kidney (MDCK) cells were investigated. The restoration of PRDX5 mitochondrial targeting in MDCK cells, instead of protecting, provokes deleterious effects following peroxide exposure independently of its peroxidase activity, indicating that mitochondrial PRDX5 gains cytotoxic properties under acute oxidative stress in MDCK cells. Altogether our results show that, although mitochondrial PRDX5 cytoprotective function against oxidative stress has been clearly demonstrated in human and rodents, PRDX5 targeting to mitochondria has been evolutionary lost in canids. Moreover, restoration of mitochondrial PRDX5 in dog MDCK cells, instead of conferring protection against peroxide exposure, makes them more vulnerable.
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Affiliation(s)
- Valérie Van der Eecken
- Institut des Sciences de la Vie, Université catholique de Louvain, Louvain-la-Neuve, Belgium
| | - André Clippe
- Institut des Sciences de la Vie, Université catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Sophie Dekoninck
- Institut des Sciences de la Vie, Université catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Julie Goemaere
- Institut des Sciences de la Vie, Université catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Geoffroy Walbrecq
- Institut des Sciences de la Vie, Université catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Paul P. Van Veldhoven
- Department of Cellular and Molecular Medicine, LIPIT, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Bernard Knoops
- Institut des Sciences de la Vie, Université catholique de Louvain, Louvain-la-Neuve, Belgium
- * E-mail:
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16
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Lloyd MD, Yevglevskis M, Lee GL, Wood PJ, Threadgill MD, Woodman TJ. α-Methylacyl-CoA racemase (AMACR): Metabolic enzyme, drug metabolizer and cancer marker P504S. Prog Lipid Res 2013; 52:220-30. [DOI: 10.1016/j.plipres.2013.01.001] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2012] [Revised: 01/14/2013] [Accepted: 01/15/2013] [Indexed: 10/27/2022]
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17
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Microbial gutta-percha degradation shares common steps with rubber degradation by Nocardia nova SH22a. Appl Environ Microbiol 2012; 79:1140-9. [PMID: 23220954 DOI: 10.1128/aem.03016-12] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Nocardia nova SH22a, a bacterium capable of degrading gutta-percha (GP) and natural rubber (NR), was used to investigate the GP degradation mechanism and the relations between the GP and NR degradation pathways. For this strain, a protocol of electroporation was systematically optimized, and an efficiency of up to 4.3 × 10(7) CFU per μg of plasmid DNA was achieved. By applying this optimized protocol to N. nova SH22a, a Tn5096-based transposon mutagenesis library of this bacterium was constructed. Among about 12,000 apramycin-resistant transformants, we identified 76 stable mutants defective in GP or NR utilization. Whereas 10 mutants were specifically defective in GP utilization, the growth of the other 66 mutants was affected on both GP and NR. This indicated that the two degradation pathways are quite similar and share many common steps. The larger number of GP-degrading defective mutants could be explained in one of two ways: either (i) the GP pathway is more complex and harbors more specific steps or (ii) the steps for both pathways are almost identical, but in the case of GP degradation there are fewer enzymes involved in each step. The analysis of transposition loci and genetic studies on interesting genes confirmed the crucial role of an α-methylacyl-coenzyme A racemase in the degradation of both GP and NR. We also demonstrated the probable involvement of enzymes participating in oxidoreduction reactions, β-oxidation, and the synthesis of complex cell envelope lipids in the degradation of GP.
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18
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Sharma S, Bhaumik P, Schmitz W, Venkatesan R, Hiltunen JK, Conzelmann E, Juffer AH, Wierenga RK. The Enolization Chemistry of a Thioester-Dependent Racemase: The 1.4 Å Crystal Structure of a Reaction Intermediate Complex Characterized by Detailed QM/MM Calculations. J Phys Chem B 2012; 116:3619-29. [DOI: 10.1021/jp210185m] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- Satyan Sharma
- Biocenter Oulu and Department
of Biochemistry, University of Oulu, P.O.
Box 3000, Oulu, FI-90014, Finland
| | - Prasenjit Bhaumik
- Protein Structure Section, Macromolecular
Crystallography Laboratory, National Cancer Institute, Frederick, Maryland 21702, United States
| | - Werner Schmitz
- Theodor-Boveri-Institut für
Biowissenschaften (Biozentrum) der Universität Würzburg, Am Hubland, D-97074 Würzburg,
Germany
| | - Rajaram Venkatesan
- Biocenter Oulu and Department
of Biochemistry, University of Oulu, P.O.
Box 3000, Oulu, FI-90014, Finland
| | - J. Kalervo Hiltunen
- Biocenter Oulu and Department
of Biochemistry, University of Oulu, P.O.
Box 3000, Oulu, FI-90014, Finland
| | - Ernst Conzelmann
- Theodor-Boveri-Institut für
Biowissenschaften (Biozentrum) der Universität Würzburg, Am Hubland, D-97074 Würzburg,
Germany
| | - André H. Juffer
- Biocenter Oulu and Department
of Biochemistry, University of Oulu, P.O.
Box 3000, Oulu, FI-90014, Finland
| | - Rik K. Wierenga
- Biocenter Oulu and Department
of Biochemistry, University of Oulu, P.O.
Box 3000, Oulu, FI-90014, Finland
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19
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Van der Eecken V, Clippe A, Van Veldhoven PP, Knoops B. Mitochondrial targeting of peroxiredoxin 5 is preserved from annelids to mammals but is absent in pig Sus scrofa domesticus. Mitochondrion 2011; 11:973-81. [PMID: 21763786 DOI: 10.1016/j.mito.2011.06.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2010] [Revised: 05/13/2011] [Accepted: 06/29/2011] [Indexed: 11/19/2022]
Abstract
Peroxiredoxin 5 (PRDX5) is a thioredoxin peroxidase able to reduce hydrogen peroxide, alkyl hydroperoxides and peroxynitrite. In human, PRDX5 was reported to be localized in the cytosol, the mitochondria, the peroxisomes and the nucleus. Mitochondrial localization results from the presence of an N-terminal mitochondrial targeting sequence (MTS). Here, we examined the conservation of mitochondrial localization of PRDX5 in animal species. We found that PRDX5 MTS is present and functional in the annelid lugworm Arenicola marina. Surprisingly, although mitochondrial targeting is well conserved among animals, PRDX5 is missing in mitochondria of domestic pig. Thus, it appears that mitochondrial targeting of PRDX5 may have been lost throughout evolution in animal species, including pig, with unknown functional consequences.
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Affiliation(s)
- Valérie Van der Eecken
- Université catholique de Louvain, Institut des Sciences de la Vie, 4-5 place Croix du Sud, B-1348 Louvain-la-Neuve, Belgium
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20
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He M, Pei Z, Mohsen AW, Watkins P, Murdoch G, Van Veldhoven PP, Ensenauer R, Vockley J. Identification and characterization of new long chain acyl-CoA dehydrogenases. Mol Genet Metab 2011; 102:418-29. [PMID: 21237683 PMCID: PMC3073726 DOI: 10.1016/j.ymgme.2010.12.005] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2010] [Accepted: 12/09/2010] [Indexed: 12/23/2022]
Abstract
Long-chain fatty acids are an important source of energy in muscle and heart where the acyl-CoA dehydrogenases (ACADs) participate in consecutive cycles of β-oxidation to generate acetyl-CoA and reducing equivalents for generating energy. However, the role of long-chain fatty acid oxidation in the brain and other tissues that do not rely on fat for energy is poorly understood. Here we characterize two new ACADs, ACAD10 and ACAD11, both with significant expression in human brain. ACAD11 utilizes substrates with primary carbon chain lengths between 20 and 26, with optimal activity towards C22CoA. The combination of ACAD11 with the newly characterized ACAD9 accommodates the full spectrum of long chain fatty acid substrates presented to mitochondrial β-oxidation in human cerebellum. ACAD10 has significant activity towards the branched-chain substrates R and S, 2 methyl-C15-CoA and is highly expressed in fetal but not adult brain. This pattern of expression is similar to that of LCAD, another ACAD previously shown to be involved in long branched chain fatty acid metabolism. Interestingly, the ACADs in human cerebellum were found to have restricted cellular distribution. ACAD9 was most highly expressed in the granular layer, ACAD11 in the white matter, and MCAD in the molecular layer and axons of specific neurons. This compartmentalization of ACADs in the human central nerve system suggests that β-oxidation in cerebellum participates in different functions other than generating energy, for example, the synthesis and/or degradation of unique cellular lipids and catabolism of aromatic amino acids, compounds that are vital to neuronal function.
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Affiliation(s)
- Miao He
- Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, PA
| | - Zhengtong Pei
- Kennedy Krieger Institute and Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Al-Walid Mohsen
- Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, PA
| | - Paul Watkins
- Kennedy Krieger Institute and Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Geoffrey Murdoch
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, PA
| | - Paul P Van Veldhoven
- Laboratory of Lipid Biochemistry and Protein Interactions, Department of Molecular Cell Biology, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Regina Ensenauer
- Ludwig-Maximilians University, Dr. von Hauner Children’s Hospital, Children’s Research Center, Munich, Germany
| | - Jerry Vockley
- Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, PA
- Department of Human Genetics, University of Pittsburgh, Graduate School of Public Health, Pittsburgh, PA
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21
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Hagey LR, Lida T, Tamegai H, Ogawa S, Une M, Asahina K, Mushiake K, Goto T, Mano N, Goto J, Krasowski MD, Hofmann AF. Major biliary bile acids of the medaka (Oryzias latipes): 25R- and 25S-epimers of 3alpha,7alpha,12alpha-trihydroxy-5beta-cholestanoic acid. Zoolog Sci 2010; 27:565-73. [PMID: 20608845 DOI: 10.2108/zsj.27.565] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The biliary bile salts of the medaka, the Japanese rice fish (Oryzias latipes) were isolated and identified. Only bile acids were present, and all were N-acylamidated with taurine. Three bile acids, constituting 98% of total bile acids, were isolated by chromatography and their structure inferred from their properties compared to those of synthetic standards when analyzed by liquid chromatographytandem mass spectrometry. The dominant bile acid was the 25R-epimer (82%) of 3alpha,7alpha,12alpha-trihydroxy-5beta-cholestan-27-oic acid. The 25S-epimer was also present (11%), as was cholic acid (5%). Complete (1)H and (13)C NMR signal assignments of the C-25 epimers were made by using a combination of several 1D- and 2D-NMR techniques. The (1)H and (13)C NMR chemical shifts and spectral patterns of the hydrogen and carbon atoms, being close to the asymmetric centered at C-25, provided confirmatory evidence in that they distinguished the two epimeric diastereomers. The medaka is the first fish species identified as having C(27) biliary bile acids as dominant among its major bile salts.
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Affiliation(s)
- Lee R Hagey
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093-0063, USA
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22
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Van Veldhoven PP. Biochemistry and genetics of inherited disorders of peroxisomal fatty acid metabolism. J Lipid Res 2010; 51:2863-95. [PMID: 20558530 DOI: 10.1194/jlr.r005959] [Citation(s) in RCA: 243] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
In humans, peroxisomes harbor a complex set of enzymes acting on various lipophilic carboxylic acids, organized in two basic pathways, alpha-oxidation and beta-oxidation; the latter pathway can also handle omega-oxidized compounds. Some oxidation products are crucial to human health (primary bile acids and polyunsaturated FAs), whereas other substrates have to be degraded in order to avoid neuropathology at a later age (very long-chain FAs and xenobiotic phytanic acid and pristanic acid). Whereas total absence of peroxisomes is lethal, single peroxisomal protein deficiencies can present with a mild or severe phenotype and are more informative to understand the pathogenic factors. The currently known single protein deficiencies equal about one-fourth of the number of proteins involved in peroxisomal FA metabolism. The biochemical properties of these proteins are highlighted, followed by an overview of the known diseases.
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Affiliation(s)
- Paul P Van Veldhoven
- Katholieke Universiteit Leuven, Department of Molecular Cell Biology, LIPIT, Campus Gasthuisberg, Herestraat, Leuven, Belgium.
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23
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Ferdinandusse S, Denis S, Faust PL, Wanders RJA. Bile acids: the role of peroxisomes. J Lipid Res 2009; 50:2139-47. [PMID: 19357427 DOI: 10.1194/jlr.r900009-jlr200] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
It is well established that peroxisomes play a crucial role in de novo bile acid synthesis. Studies in patients with a peroxisomal disorder have been indispensable for the elucidation of the precise role of peroxisomes. Several peroxisomal disorders are associated with distinct bile acid abnormalities and each disorder has a characteristic pattern of abnormal bile acids that accumulate, which is often used for diagnostic purposes. The patients have also been important for determining the pathophysiological consequences of defects in bile acid biosynthesis. In this review, we will discuss all the peroxisomal steps involved in bile acid synthesis and the bile acid abnormalities in patients with peroxisomal disorders. We will show the results of bile acid measurements in several tissues from patients, including brain, and we will discuss the toxicity and the pathological effects of the abnormal bile acids.
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Affiliation(s)
- Sacha Ferdinandusse
- Laboratory of Genetic Metabolic Diseases, Academic Medical Center at the University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands.
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24
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Moeller G, Adamski J. Integrated view on 17beta-hydroxysteroid dehydrogenases. Mol Cell Endocrinol 2009; 301:7-19. [PMID: 19027824 DOI: 10.1016/j.mce.2008.10.040] [Citation(s) in RCA: 158] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2008] [Revised: 10/27/2008] [Accepted: 10/27/2008] [Indexed: 10/21/2022]
Abstract
17beta-Hydroxysteroid dehydrogenases (17beta-HSDs) are important enzymes in steroid metabolism. Long known members of the protein family seemed to be well characterised concerning their role in the regulation of the biological potency of steroid hormones, but today more and more evidence points to pivotal contributions of these enzymes in a variety of other metabolic pathways. Therefore, studies on 17beta-HSDs develop towards metabolomic survey. Latest research results give new insights into the complex metabolic interconnectivity of the 17beta-HSDs. In this paper metabolic activities of 17beta-HSDs will be compared, their interplay with endogenous substrates summarised, and interlacing pathways depicted. Strategies on deciphering the physiological role of 17beta-HSDs and the genetic predisposition for associated diseases will be presented.
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Affiliation(s)
- Gabriele Moeller
- Helmholtz Zentrum München, German Research Center for Environmental Health, Institute of Experimental Genetics, Genome Analysis Center, Neuherberg, Germany.
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25
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Abstract
The metabolism of steroids at position 17 is catalysed by a growing number of 17beta-hydroxysteroid dehydrogenases (17beta-HSDs). Several human diseases like breast or prostate cancer, endometriosis,metabolic syndrome and mental diseases were associated with dysfunctions of 17beta-HSDs, which consequently became drug targets. This review will focus on identities of 17beta-HSDs and recent advances in analyses of their physiological roles in steroid and lipid metabolism. It will also address the potential of metabolomics in drug development.
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Affiliation(s)
- Cornelia Prehn
- Helmholtz Zentrum München, German Research Center for Environmental Health, Institute of Experimental Genetics, Genome Analysis Center, Neuherberg, Germany
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26
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Presence of thiamine pyrophosphate in mammalian peroxisomes. BMC BIOCHEMISTRY 2007; 8:10. [PMID: 17596263 PMCID: PMC1913525 DOI: 10.1186/1471-2091-8-10] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/02/2007] [Accepted: 06/27/2007] [Indexed: 12/02/2022]
Abstract
Background Thiamine pyrophosphate (TPP) is a cofactor for 2-hydroxyacyl-CoA lyase 1 (HACL1), a peroxisomal enzyme essential for the α-oxidation of phytanic acid and 2-hydroxy straight chain fatty acids. So far, HACL1 is the only known peroxisomal TPP-dependent enzyme in mammals. Little is known about the transport of metabolites and cofactors across the peroxisomal membrane and no peroxisomal thiamine or TPP carrier has been identified in mammals yet. This study was undertaken to get a better insight into these issues and to shed light on the role of TPP in peroxisomal metabolism. Results Because of the crucial role of the cofactor TPP, we reanalyzed its subcellular localization in rat liver. In addition to the known mitochondrial and cytosolic pools, we demonstrated, for the first time, that peroxisomes contain TPP (177 ± 2 pmol/mg protein). Subsequently, we verified whether TPP could be synthesized from its precursor thiamine, in situ, by a peroxisomal thiamine pyrophosphokinase (TPK). However, TPK activity was exclusively recovered in the cytosol. Conclusion Our results clearly indicate that mammalian peroxisomes do contain TPP but that no pyrophosphorylation of thiamine occurs in these organelles, implying that thiamine must enter the peroxisome already pyrophosphorylated. Consequently, TPP entry may depend on a specific transport system or, in a bound form, on HACL1 translocation.
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Ferdinandusse S, Houten SM. Peroxisomes and bile acid biosynthesis. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2006; 1763:1427-40. [PMID: 17034878 DOI: 10.1016/j.bbamcr.2006.09.001] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2006] [Revised: 08/24/2006] [Accepted: 09/01/2006] [Indexed: 01/11/2023]
Abstract
Peroxisomes play an important role in the biosynthesis of bile acids because a peroxisomal beta-oxidation step is required for the formation of the mature C24-bile acids from C27-bile acid intermediates. In addition, de novo synthesized bile acids are conjugated within the peroxisome. In this review, we describe the current state of knowledge about all aspects of peroxisomal function in bile acid biosynthesis in health and disease. The peroxisomal enzymes involved in the synthesis of bile acids have been identified, and the metabolic and pathologic consequences of a deficiency of one of these enzymes are discussed, including the potential role of nuclear receptors therein.
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Affiliation(s)
- Sacha Ferdinandusse
- Laboratory Genetic Metabolic Diseases, Department of Clinical Chemistry, F0-224 Academic Medical Center at the University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, the Netherlands.
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Poirier Y, Antonenkov VD, Glumoff T, Hiltunen JK. Peroxisomal beta-oxidation--a metabolic pathway with multiple functions. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2006; 1763:1413-26. [PMID: 17028011 DOI: 10.1016/j.bbamcr.2006.08.034] [Citation(s) in RCA: 333] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2006] [Revised: 08/21/2006] [Accepted: 08/23/2006] [Indexed: 12/15/2022]
Abstract
Fatty acid degradation in most organisms occurs primarily via the beta-oxidation cycle. In mammals, beta-oxidation occurs in both mitochondria and peroxisomes, whereas plants and most fungi harbor the beta-oxidation cycle only in the peroxisomes. Although several of the enzymes participating in this pathway in both organelles are similar, some distinct physiological roles have been uncovered. Recent advances in the structural elucidation of numerous mammalian and yeast enzymes involved in beta-oxidation have shed light on the basis of the substrate specificity for several of them. Of particular interest is the structural organization and function of the type 1 and 2 multifunctional enzyme (MFE-1 and MFE-2), two enzymes evolutionarily distant yet catalyzing the same overall enzymatic reactions but via opposite stereochemistry. New data on the physiological roles of the various enzymes participating in beta-oxidation have been gathered through the analysis of knockout mutants in plants, yeast and animals, as well as by the use of polyhydroxyalkanoate synthesis from beta-oxidation intermediates as a tool to study carbon flux through the pathway. In plants, both forward and reverse genetics performed on the model plant Arabidopsis thaliana have revealed novel roles for beta-oxidation in the germination process that is independent of the generation of carbohydrates for growth, as well as in embryo and flower development, and the generation of the phytohormone indole-3-acetic acid and the signal molecule jasmonic acid.
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Affiliation(s)
- Yves Poirier
- Department of Plant Molecular Biology, Biophore, University of Lausanne, CH-1015 Lausanne, Switzerland
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Nagayoshi Y, Ohba T, Yamamoto H, Miyahara Y, Tashiro H, Katabuchi H, Okamura H. Characterization of 17beta-hydroxysteroid dehydrogenase type 4 in human ovarian surface epithelial cells. Mol Hum Reprod 2005; 11:615-21. [PMID: 16219629 DOI: 10.1093/molehr/gah215] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The human ovarian surface epithelium (hOSE) is a single layer of mesothelial-type primitive epithelial cells that are potential estrogen targets. It has been reported that hOSE cells can produce estrogen. However, the mechanisms that regulate estrogen level(s) in hOSE cells are not yet known. To elucidate the enzymes involved in these reactions, we examined gene expression of 17beta-hydroxysteroid dehydrogenases (17beta-HSDs) in primary hOSE (POSE) and OSE2a cells using RT-PCR. We found that POSE cells and cells of the immortalized hOSE line, OSE2a, bidirectionally converted estrone (E1) and 17beta-estradiol (E2). Both cell types expressed mRNA for 17beta-HSD type 1 (17beta-HSD1), suggesting that the enzyme is involved in the E1 to E2 conversion. Interestingly, both cells expressed 17beta-HSD4 mRNA but not 17beta-HSD2 mRNA. We prepared an antibody against the carboxyl terminal of 17beta-HSD4 (anti-17beta-HSD4 antibody), which recognized the 80 and 48 kDa proteins in POSE and OSE2a cells based on immunoblot analysis. Furthermore, immunohistochemical study revealed the presence of 17beta-HSD4 in hOSE cells in the human ovary. These results suggest that 17beta-HSD4 is involved in estrogen inactivation and may protect against an excessive accumulation of E2 in hOSE cells.
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Affiliation(s)
- Y Nagayoshi
- Department of Reproductive Medicine and Surgery, Graduate School of Medical Sciences, Kumamoto University, Honjo, Kumamoto, Japan.
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Foulon V, Sniekers M, Huysmans E, Asselberghs S, Mahieu V, Mannaerts GP, Van Veldhoven PP, Casteels M. Breakdown of 2-hydroxylated straight chain fatty acids via peroxisomal 2-hydroxyphytanoyl-CoA lyase: a revised pathway for the alpha-oxidation of straight chain fatty acids. J Biol Chem 2005; 280:9802-12. [PMID: 15644336 DOI: 10.1074/jbc.m413362200] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
2-Hydroxyfatty acids, constituents of brain cerebrosides and sulfatides, were previously reported to be degraded by an alpha-oxidation system, generating fatty acids shortened by one carbon atom. In the current study we used labeled and unlabeled 2-hydroxyoctadecanoic acid to reinvestigate the degradation of this class of lipids. Both in intact and broken cell systems formate was identified as a main reaction product. Furthermore, the generation of an n-1 aldehyde was demonstrated. In permeabilized rat hepatocytes and liver homogenates, studies on cofactor requirements revealed a dependence on ATP, CoA, Mg(2+), thiamine pyrophosphate, and NAD(+). Together with subcellular fractionation data and studies on recombinant enzymes, this led to the following picture. In a first step, the 2-hydroxyfatty acid is activated to an acyl-CoA; subsequently, the 2-hydroxy fatty acyl-CoA is cleaved by 2-hydroxyphytanoyl-CoA lyase, to formyl-CoA and an n-1 aldehyde. The severe inhibition of formate generation by oxythiamin treatment of intact fibroblasts indicates that cleavage through the thiamine pyrophosphate-dependent 2-hydroxyphytanoyl-CoA lyase is the main pathway for the degradation of 2-hydroxyfatty acids. The latter protein was initially characterized as an essential enzyme in the peroxisomal alpha-oxidation of 3-methyl-branched fatty acids such as phytanic acid. Our findings point to a new role for peroxisomes in mammals, i.e. the breakdown of 2-hydroxyfatty acids, at least the long chain 2-hydroxyfatty acids. Most likely, the more abundant very long chain 2-hydroxyfatty acids are degraded in a similar manner.
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Affiliation(s)
- Veerle Foulon
- Afdeling Farmacologie, Departement Celbiologie, Katholieke Universiteit Leuven, Campus Gasthuisberg, 3000 Leuven, Belgium
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Sakai Y, Takahashi H, Wakasa Y, Kotani T, Yurimoto H, Miyachi N, Van Veldhoven PP, Kato N. Role of alpha-methylacyl coenzyme A racemase in the degradation of methyl-branched alkanes by Mycobacterium sp. strain P101. J Bacteriol 2004; 186:7214-20. [PMID: 15489432 PMCID: PMC523219 DOI: 10.1128/jb.186.21.7214-7220.2004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A new isolate, Mycobacterium sp. strain P101, is capable of growth on methyl-branched alkanes (pristane, phytane, and squalane). Among ca. 10,000 Tn5-derived mutants, we characterized 2 mutants defective in growth on pristane or n-hexadecane. A single copy of Tn5 was found to be inserted into the coding region of mcr (alpha-methylacyl coenzyme A [alpha-methylacyl-CoA] racemase gene) in mutant P1 and into the coding region of mls (malate synthase gene) in mutant H1. Mutant P1 could not grow on methyl-branched alkanes. The recombinant Mcr produced in Escherichia coli was confirmed to catalyze racemization of (R)-2-methylpentadecanoyl-CoA, with a specific activity of 0.21 micromol . min(-1) . mg of protein(-1). Real-time quantitative reverse transcriptase PCR analyses indicated that mcr gene expression was enhanced by the methyl-branched alkanes pristane and squalane. Mutant P1 used (S)-2-methylbutyric acid for growth but did not use the racemic compound, and growth on n-hexadecane was not inhibited by pristane. These results suggested that the oxidation of the methyl-branched alkanoic acid is inhibited by the (R) isomer, although the (R) isomer was not toxic during growth on n-hexadecane. Based on these results, Mcr is suggested to play a critical role in beta-oxidation of methyl-branched alkanes in Mycobacterium. On the other hand, mutant H1 could not grow on n-hexadecane, but it partially retained the ability to grow on pristane. The reduced growth of mutant H1 on pristane suggests that propionyl-CoA is available for cell propagation through the 2-methyl citric acid cycle, since propionyl-CoA is produced through beta-oxidation of pristane.
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Affiliation(s)
- Yasuyoshi Sakai
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kitashirakawa, Sakyo-ku, Kyoto 606-8502, Japan
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Savolainen K, Kotti TJ, Schmitz W, Savolainen TI, Sormunen RT, Ilves M, Vainio SJ, Conzelmann E, Hiltunen JK. A mouse model for α-methylacyl-CoA racemase deficiency: adjustment of bile acid synthesis and intolerance to dietary methyl-branched lipids. Hum Mol Genet 2004; 13:955-65. [PMID: 15016763 DOI: 10.1093/hmg/ddh107] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
alpha-Methylacyl-CoA racemase (Amacr) deficiency in humans leads to sensory motor neuronal and liver abnormalities. The disorder is recessively inherited and caused by mutations in the AMACR gene, which encodes Amacr, an enzyme presumed to be essential for bile acid synthesis and to participate in the degradation of methyl-branched fatty acids. To generate a model to study the pathophysiology in Amacr deficiency we inactivated the mouse Amacr gene. As per human Amacr deficiency, the Amacr(-/-) mice showed accumulation (44-fold) of C27 bile acid precursors and decreased (over 50%) primary (C24) bile acids in bile, serum and liver, however the Amacr(-/-) mice were clinically symptomless. Real-time quantitative PCR analysis showed that, among other responses, the level of mRNA for peroxisomal multifunctional enzyme type 1 (pMFE-1) was increased 3-fold in Amacr(-/-) mice. This enzyme can be placed, together with CYP3A11 and CYP46A1, to make an Amacr-independent pathway for the generation of C24 bile acids. Exposure of Amacr(-/-) mice to a diet supplemented with phytol, a source for branched-chain fatty acids, triggered the development of a disease state with liver manifestations, redefining the physiological significance of Amacr. Amacr is indispensable for the detoxification of dietary methyl-branched lipids and, although it contributes normally to bile acid synthesis from cholesterol, the putative pMFE-1-mediated cholesterol degradation can provide for generation of bile acids, allowing survival without Amacr. Based upon our mouse model, we propose elimination of phytol from the diet of patients suffering from Amacr deficiency.
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Affiliation(s)
- Kalle Savolainen
- Department of Biochemistry, Biocenter Oulu, University of Oulu, FIN-90014, Finland
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Mukherji M, Schofield CJ, Wierzbicki AS, Jansen GA, Wanders RJA, Lloyd MD. The chemical biology of branched-chain lipid metabolism. Prog Lipid Res 2003; 42:359-76. [PMID: 12814641 DOI: 10.1016/s0163-7827(03)00016-x] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Mammalian metabolism of some lipids including 3-methyl and 2-methyl branched-chain fatty acids occurs within peroxisomes. Such lipids, including phytanic and pristanic acids, are commonly found within the human diet and may be derived from chlorophyll in plant extracts. Due to the presence of a methyl group at its beta-carbon, the well-characterised beta-oxidation pathway cannot degrade phytanic acid. Instead its alpha-methylene group is oxidatively excised to give pristanic acid, which can be metabolised by the beta-oxidation pathway. Many defects in the alpha-oxidation pathway result in an accumulation of phytanic acid, leading to neurological distress, deterioration of vision, deafness, loss of coordination and eventual death. Details of the alpha-oxidation pathway have only recently been elucidated, and considerable progress has been made in understanding the detailed enzymology of one of the oxidative steps within this pathway. This review summarises these recent advances and considers the roles and likely mechanisms of the enzymes within the alpha-oxidation pathway.
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Affiliation(s)
- Mridul Mukherji
- The Oxford Centre for Molecular Sciences & The Dyson Perrins Laboratory, South Parks Road, Oxford OX1 3QY, UK
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Setchell KDR, Heubi JE, Bove KE, O'Connell NC, Brewsaugh T, Steinberg SJ, Moser A, Squires RH. Liver disease caused by failure to racemize trihydroxycholestanoic acid: gene mutation and effect of bile acid therapy. Gastroenterology 2003; 124:217-32. [PMID: 12512044 DOI: 10.1053/gast.2003.50017] [Citation(s) in RCA: 122] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
BACKGROUND & AIMS Inborn errors of bile acid metabolism may present as neonatal cholestasis and fat-soluble vitamin malabsorption or as late onset chronic liver disease. Our aim was to fully characterize a defect in bile acid synthesis in a 2-week-old African-American girl presenting with coagulopathy, vitamin D and E deficiencies, and mild cholestasis and in her sibling, whose liver had been used for orthotopic liver transplantation (OLT). METHODS Bile acids were measured by mass spectrometry in urine, bile, serum, and feces of the patient and in urine from the unrelated recipient. RESULTS Liver biopsy specimens showed neonatal hepatitis with giant cell transformation and hepatocyte necrosis; peroxisomes were reduced in number. High concentrations of (25R)3alpha,7alpha,12alpha-trihydroxy-5beta-cholestanoic acid in the urine, bile, and serum established a pattern similar to that of Zellweger syndrome and identical to the Alligator mississippiensis. Serum phytanic acid was normal, whereas pristanic acid was markedly elevated. Biochemical, MRI, and neurologic findings were inconsistent with a generalized defect of peroxisomal function and were unique. Analysis of the urine from the recipient of the deceased sibling's liver confirmed the same bile acid synthetic defect. A deficiency in 2-methylacyl-CoA racemase, which is essential for conversion of (25R)THCA to its 25S-isomer, the substrate to initiate peroxisomal beta-oxidation to primary bile acids, was confirmed by DNA analysis revealing a missense mutation (S52P) in the gene encoding this enzyme. Long-term treatment with cholic acid normalized liver enzymes and prevented progression of symptoms. CONCLUSIONS This genetic defect further highlights bile acid synthetic defects as a cause of neonatal cholestasis.
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Affiliation(s)
- Kenneth D R Setchell
- Division of Clinical Mass Spectrometry, Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH 45229, USA.
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Ullan RV, Casqueiro J, Banuelos O, Fernandez FJ, Gutierrez S, Martin JF. A novel epimerization system in fungal secondary metabolism involved in the conversion of isopenicillin N into penicillin N in Acremonium chrysogenum. J Biol Chem 2002; 277:46216-25. [PMID: 12228250 DOI: 10.1074/jbc.m207482200] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The epimerization step that converts isopenicillin N into penicillin N during cephalosporin biosynthesis has remained uncharacterized despite its industrial relevance. A transcriptional analysis of a 9-kb region located downstream of the pcbC gene revealed the presence of two transcripts that correspond to the genes named cefD1 and cefD2 encoding proteins with high similarity to long chain acyl-CoA synthetases and acyl-CoA racemases from Mus musculus, Homo sapiens, and Rattus norvegicus. Both genes are expressed in opposite orientations from a bidirectional promoter region. Targeted inactivation of cefD1 and cefD2 was achieved by the two-marker gene replacement procedure. Disrupted strains lacked isopenicillin N epimerase activity, were blocked in cephalosporin C production, and accumulated isopenicillin N. Complementation in trans of the disrupted nonproducer mutant with both genes restored epimerase activity and cephalosporin biosynthesis. However, when cefD1 or cefD2 were introduced separately into the double-disrupted mutant, no epimerase activity was detected, indicating that the concerted action of both proteins encoded by cefD1 and cefD2 is required for epimerization of isopenicillin N into penicillin N. This epimerization system occurs in eukaryotic cells and is entirely different from the known epimerization systems involved in the biosynthesis of bacterial beta-lactam antibiotics.
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Affiliation(s)
- Ricardo V Ullan
- Area de Microbiologia, Facultad de Ciencias Biológicas y Ambientales, Universidad de León, 24071 León, Spain
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Luo YS, Nicaud JM, Van Veldhoven PP, Chardot T. The acyl-CoA oxidases from the yeast Yarrowia lipolytica: characterization of Aox2p. Arch Biochem Biophys 2002; 407:32-8. [PMID: 12392712 DOI: 10.1016/s0003-9861(02)00466-6] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
One of the acyl-CoA oxidases from the yeast Yarrowia lipolytica, acyl-CoA oxidase 2 (Aox2p), has been expressed in Escherichia coli as an active, N-terminally tagged (His)(6) fusion protein. The specific activity of the purified enzyme, containing FAD, was 19.7 micromolmin(-1)mg(-1) using myristoyl-CoA as substrate. Using substrates with different chain lengths and different substituents, its kinetic properties were further analyzed. Straight-chain acyl-CoAs, with a chain length of 10-14C, are well oxidized, reflecting the properties of Aox2p as deduced from in vivo studies. Acyl-CoAs containing more than 14C were also desaturated, if their concentration was below 25 microM or if proteins capable of binding these CoA-esters, such as albumin or beta-casein, were added to the assay. These long-chain acyl-CoAs, although poor substrates, acted as competitors for the short- and medium-chain substrates. Compared to palmitoyl-CoA, activity toward hexadecadioyl-CoA, containing a omega-carboxy group, was similar. Taken together, these data suggest that micelles of long-chain acyl-CoAs are able to bind and inhibit Aox2p. The enzyme was also active toward acyl-CoA-esters containing a 2-methyl group, but only the 2S isomer was recognized.
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Affiliation(s)
- Yi Shan Luo
- Laboratoire de Chimie Biologique, INRA INA-PG, Centre de Biotechnologie Agro-Industrielle, Thiverval-Grignon, France
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Cuebas DA, Phillips C, Schmitz W, Conzelmann E, Novikov DK. The role of alpha-methylacyl-CoA racemase in bile acid synthesis. Biochem J 2002; 363:801-7. [PMID: 11964182 PMCID: PMC1222534 DOI: 10.1042/0264-6021:3630801] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
According to current views, the second peroxisomal beta-oxidation pathway is responsible for the degradation of the side chain of bile acid intermediates. Peroxisomal multifunctional enzyme type 2 [peroxisomal multifunctional 2-enoyl-CoA hydratase/(R)-3-hydroxyacyl-CoA dehydrogenase; MFE-2] catalyses the second (hydration) and third (dehydrogenation) reactions of the pathway. Deficiency of MFE-2 leads to accumulation of very-long-chain fatty acids, 2-methyl-branched fatty acids and C(27) bile acid intermediates in plasma, but bile acid synthesis is not blocked completely. In this study we describe an alternative pathway, which allows MFE-2 deficiency to be overcome. The alternative pathway consists of alpha-methylacyl-CoA racemase and peroxisomal multifunctional enzyme type 1 [peroxisomal multifunctional 2-enoyl-CoA hydratase/(S)-3-hydroxyacyl-CoA dehydrogenase; MFE-1]. (24E)-3alpha,7alpha,12alpha-Trihydroxy-5beta-cholest-24-enoyl-CoA, the presumed physiological isomer, is hydrated by MFE-1 with the formation of (24S,25S)-3alpha,7alpha,12alpha,24-tetrahydroxy-5beta-cholestanoyl-CoA [(24S,25S)-24-OH-THCA-CoA], which after conversion by a alpha-methylacyl-CoA racemase into the (24S,25R) isomer can again be dehydrogenated by MFE-1 to 24-keto-3alpha,7alpha,12alpha-trihydroxycholestanoyl-CoA, a physiological intermediate in cholic acid synthesis. The discovery of the alternative pathway of cholesterol side-chain oxidation will improve diagnosis of peroxisomal deficiencies by identification of serum 24-OH-THCA-CoA diastereomer profiles.
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Affiliation(s)
- Dean A Cuebas
- Department of Chemistry, Southwest Missouri State University, Springfield, MO 65804, USA
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Ferdinandusse S, Rusch H, van Lint A, Dacremont G, Wanders R, Vreken P. Stereochemistry of the peroxisomal branched-chain fatty acid α- and β-oxidation systems in patients suffering from different peroxisomal disorders. J Lipid Res 2002. [DOI: 10.1016/s0022-2275(20)30150-4] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Van Veldhoven PP, Meyhi E, Squires RH, Fransen M, Fournier B, Brys V, Bennett MJ, Mannaerts GP. Fibroblast studies documenting a case of peroxisomal 2-methylacyl-CoA racemase deficiency: possible link between racemase deficiency and malabsorption and vitamin K deficiency. Eur J Clin Invest 2001; 31:714-22. [PMID: 11473573 DOI: 10.1046/j.1365-2362.2001.00877.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
BACKGROUND 2-Methylacyl-CoA racemase interconverts the 2-methyl group of pristanoyl-CoA or the 25-methyl group of hydroxylated cholestanoyl-CoAs, allowing further peroxisomal desaturation of these compounds in man by the branched chain acyl-CoA oxidase, which recognise only the S-isomers. Hence, oxidation studies in fibroblasts, currently based on the use of racemic substrates such as [1-14C] pristanic acid, do not allow us to distinguish between a deficient racemase or an impaired oxidase. DESIGN To evaluate the racemase activity directly, the 2R-isomer of[1-14C] pristanic acid, as well as the 2R-isomer of 2-methyl-[1-14C] hexadecanoic, a synthetic pristanic acid substitute, were prepared and their degradation by cultured human skin fibroblasts was compared to that of the racemic substrates. RESULTS In fibroblasts in a young girl, presenting with elevated urinary levels of trihydroxycholestanoic acid metabolites but normal plasma levels of very long chain fatty acids, a partial deficient degradation of racemic [1-14C] pristanic acid was observed. Incorporation of 2R-[1-14C] pristanic acid in glycerolipids of the patient's fibroblasts proceeded normally, but breakdown was impaired. Similar findings were seen with the 2R-isomer of 2-methyl-[1-14C] hexadecanoic. These data, combined with the fact that the branched chain acyl-CoA oxidase, catalyzing the first oxidation step of pristanic acid and bile acid intermediates in man, appeared normal, suggested a peroxisomal beta-oxidation defect in the patient at the level of 2-methylacyl-CoA racemase. CONCLUSION Carboxy-labelled 2R-methyl branched chain fatty acids might be useful tools to document cases of racemase deficiencies. Because a brother of the patient died with a diagnosis of vitamin K deficiency, an impaired racemase might be responsible for other cases of unexplicable malabsorption.
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Affiliation(s)
- P P Van Veldhoven
- Katholieke Universiteit Leuven, Afdeling Farmacologie, Leuven, Belgium.
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Abstract
Peroxisomal disorders appear with a frequency of 1:5000 in newborns. They are caused either by peroxisomal assembly defects or by deficiencies of single peroxisomal enzymes. The phenotypes vary widely: affected humans may die very early in life within a few days to several months as a result of the impairment in essential peroxisomal functions as, for example, in Zellweger syndrome, or they may show only minor disabilities as is in acatalasemia. The deficiency of D-bifunctional protein, an enzyme involved in peroxisomal beta-oxidation of certain fatty acids and the synthesis of bile acids, causes a very severe, Zellweger-like phenotype. A number of different mutations in the gene coding for the enzyme were found in humans causing the total or partial loss of its enzymatic function. This paper gives a review of cases and their molecular basis.
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Affiliation(s)
- G Möller
- GSF-National Research Center of Environment and Health, Institute of Experimental Genetics, Ingolstädter Landstrasse 1, 85764, Neuherberg, Germany.
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Ferdinandusse S, Overmars H, Denis S, Waterham HR, Wanders RJ, Vreken P. Plasma analysis of di- and trihydroxycholestanoic acid diastereoisomers in peroxisomal α-methylacyl-CoA racemase deficiency. J Lipid Res 2001. [DOI: 10.1016/s0022-2275(20)32345-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Amery L, Fransen M, De Nys K, Mannaerts GP, Van Veldhoven PP. Mitochondrial and peroxisomal targeting of 2-methylacyl-CoA racemase in humans. J Lipid Res 2000. [DOI: 10.1016/s0022-2275(20)31968-4] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Ferdinandusse S, Denis S, IJlst L, Dacremont G, Waterham HR, Wanders RJ. Subcellular localization and physiological role of α-methylacyl-CoA racemase. J Lipid Res 2000. [DOI: 10.1016/s0022-2275(20)31983-0] [Citation(s) in RCA: 135] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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44
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Kotti TJ, Savolainen K, Helander HM, Yagi A, Novikov DK, Kalkkinen N, Conzelmann E, Hiltunen JK, Schmitz W. In mouse alpha -methylacyl-CoA racemase, the same gene product is simultaneously located in mitochondria and peroxisomes. J Biol Chem 2000; 275:20887-95. [PMID: 10770938 DOI: 10.1074/jbc.m002067200] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
alpha-Methylacyl-CoA racemase, an enzyme of the bile acid biosynthesis and branched chain fatty acid degradation pathway, was studied at the protein, cDNA, and genomic levels in mouse liver. Immunoelectron microscopy and subcellular fractionation located racemase to mitochondria and peroxisomes. The enzymes were purified from both organelles with immunoaffinity chromatography. The isolated proteins were of the same size, with identical N-terminal amino acid sequences, and the existence of additional proteins with alpha-methylacyl-CoA racemase activity was excluded. A racemase gene of about 15 kilobases was isolated. Southern blot analysis and chromosomal localization showed that only one racemase gene is present, on chromosome 15, region 15B1. The putative initial ATG in the racemase gene was preceded by a functional promotor as shown with the luciferase reporter gene assay. The corresponding cDNAs were isolated from rat and mouse liver. The recombinant rat protein was overexpressed in active form in Pichia pastoris. The presented data suggest that the polypeptide encoded by the racemase gene can alternatively be targeted to peroxisomes or mitochondria without modifications. It is concluded that the noncleavable N-terminal sequence of the polypeptide acts as a weak mitochondrial and that the C-terminal sequence acts as a peroxisomal targeting signal.
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Affiliation(s)
- T J Kotti
- Biocenter Oulu and Department of Biochemistry, University of Oulu, Linnanmaa, Oulu FIN-90014, Finland
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Van Veldhoven PP, Mannaerts GP. Role and organization of peroxisomal beta-oxidation. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2000; 466:261-72. [PMID: 10709653 DOI: 10.1007/0-306-46818-2_31] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
In mammals, peroxisomes are involved in breakdown of very long chain fatty acids, prostanoids, pristanic acid, dicarboxylic fatty acids, certain xenobiotics and bile acid intermediates. Substrate spectrum and specificity studies of the four different beta-oxidation steps in rat and/or in man demonstrate that these substrates are degraded by separate beta-oxidation systems composed of different enzymes. In both species, the enzymes acting on straight chain fatty acids are palmitoyl-CoA oxidase, an L-specific multifunctional protein (MFP-1) and a dimeric thiolase. In liver, bile acid intermediates undergo one cycle of beta-oxidation catalyzed by trihydroxycoprostanoyl-CoA oxidase (in rat), or branched chain acyl-CoA oxidase (in man), a D-specific multifunctional protein (MFP-2) and SCPX-thiolase. Finally, pristanic acid is degraded in rat tissues by pristanoyl-CoA oxidase, the D-specific multifunctional protein-2 and SCPX-thiolase. Although in man a pristanoyl-CoA oxidase gene is present, so far its product has not been found. Hence, pristanoyl-CoA is believed to be desaturated in human tissues by the branched chain acyl-CoA oxidase. Due to the stereospecificity of the oxidases acting on 2-methyl-branched substrates, an additional enzyme, 2-methylacyl-CoA racemase, is required for the degradation of pristanic acid and the formation of bile acids.
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Hiltunen JK, Qin Y. beta-oxidation - strategies for the metabolism of a wide variety of acyl-CoA esters. BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1484:117-28. [PMID: 10760462 DOI: 10.1016/s1388-1981(00)00013-5] [Citation(s) in RCA: 101] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Living organisms are exposed to a number of different fatty acids and their various derivatives arising either via endogenous synthesis or from exogenous sources. These hydrophobic compounds can play specific metabolic, structural or endocrinic functions in the organisms before their elimination, which can be metabolism to CO(2) or to more polar lipid metabolites allowing their excretion. Quantitatively, one of the major pathways metabolizing fatty acids is beta-oxidation, which consists of a set of four reactions operating at the carbons 2 or 3 of acyl-CoA esters and shortening of the acyl-chain. To allow the beta-oxidation of acyl groups with various steric variants to proceed, different strategies have been developed. These strategies include evolution of beta-oxidation enzymes as paralogues showing specificity with respect to either chain-length or modified acyl-chain, metabolic compartmentalization in eukaryotic cells, controlling of substrate transport across membranes, development of auxiliary enzyme systems, acquisition of enzymes with adaptive active sites and recruiting and optimizing enzymes from non-homologous sources allowing them to catalyze a parallel set of reactions with different substrate specificities.
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Affiliation(s)
- J K Hiltunen
- Biocenter Oulu and Department of Biochemistry, University of Oulu, P. O. FIN-90014, Oulun yliopisto, Finland.
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Phytanoyl-CoA hydroxylase: recognition of 3-methyl-branched acyl-CoAs and requirement for GTP or ATP and Mg2+ in addition to its known hydroxylation cofactors. J Lipid Res 2000. [DOI: 10.1016/s0022-2275(20)32411-1] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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48
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Qin YM, Haapalainen AM, Kilpeläinen SH, Marttila MS, Koski MK, Glumoff T, Novikov DK, Hiltunen JK. Human peroxisomal multifunctional enzyme type 2. Site-directed mutagenesis studies show the importance of two protic residues for 2-enoyl-CoA hydratase 2 activity. J Biol Chem 2000; 275:4965-72. [PMID: 10671535 DOI: 10.1074/jbc.275.7.4965] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Beta-oxidation of acyl-CoAs in mammalian peroxisomes can occur via either multifunctional enzyme type 1 (MFE-1) or type 2 (MFE-2), both of which catalyze the hydration of trans-2-enoyl-CoA and the dehydrogenation of 3-hydroxyacyl-CoA, but with opposite chiral specificity. Amino acid sequence alignment of the 2-enoyl-CoA hydratase 2 domain in human MFE-2 with other MFE-2s reveals conserved protic residues: Tyr-347, Glu-366, Asp-370, His-406, Glu-408, Tyr-410, Asp-490, Tyr-505, Asp-510, His-515, Asp-517, and His-532. To investigate their potential roles in catalysis, each residue was replaced by alanine in site-directed mutagenesis, and the resulting constructs were tested for complementation in a yeast. After additional screening, the wild type and noncomplementing E366A and D510A variants were expressed and characterized. The purified proteins have similar secondary structural elements, with the same subunit composition. The E366A variant had a k(cat)/K(m) value 100 times lower than that of the wild type MFE-2 at pH 5, whereas the D510A variant was inactive. Asp-510 was imbedded in a novel hydratase 2 motif found in the hydratase 2 proteins. The data show that the hydratase 2 reaction catalyzed by MFE-2 requires two protic residues, Glu-366 and Asp-510, suggesting that their catalytic role may be equivalent to that of the two catalytic residues of hydratase 1.
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Affiliation(s)
- Y M Qin
- Biocenter Oulu and Department of Biochemistry, University of Oulu, Box 3000, FIN-90014 Oulun Yliopisto, Finland
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Ferdinandusse S, Denis S, Clayton PT, Graham A, Rees JE, Allen JT, McLean BN, Brown AY, Vreken P, Waterham HR, Wanders RJ. Mutations in the gene encoding peroxisomal alpha-methylacyl-CoA racemase cause adult-onset sensory motor neuropathy. Nat Genet 2000; 24:188-91. [PMID: 10655068 DOI: 10.1038/72861] [Citation(s) in RCA: 152] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Sensory motor neuropathy is associated with various inherited disorders including Charcot-Marie-Tooth disease, X-linked adrenoleukodystrophy/adrenomyeloneuropathy and Refsum disease. In the latter two, the neuropathy is thought to result from the accumulation of specific fatty acids. We describe here three patients with elevated plasma concentrations of pristanic acid (a branched-chain fatty acid) and C27-bile-acid intermediates. Two of the patients suffered from adult-onset sensory motor neuropathy. One patient also had pigmentary retinopathy, suggesting Refsum disease, whereas the other patient had upper motor neuron signs in the legs, suggesting adrenomyeloneuropathy. The third patient was a child without neuropathy. In all three patients we discovered a deficiency of alpha-methylacyl-CoA racemase (AMACR). This enzyme is responsible for the conversion of pristanoyl-CoA and C27-bile acyl-CoAs to their (S)-stereoisomers, which are the only stereoisomers that can be degraded via peroxisomal beta-oxidation. Sequence analysis of AMACR cDNA from the patients identified two different mutations that are likely to cause disease, based on analysis in Escherichia coli. Our findings have implications for the diagnosis of adult-onset neuropathies of unknown aetiology.
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Affiliation(s)
- S Ferdinandusse
- Department of Clinical Chemistry, Emma Children's Hospital, Academic Medical Center, University of Amsterdam, The Netherlands
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Abstract
Oxygenated derivatives of cholesterol (oxysterols) present a remarkably diverse profile of biological activities, including effects on sphingolipid metabolism, platelet aggregation, apoptosis, and protein prenylation. The most notable oxysterol activities center around the regulation of cholesterol homeostasis, which appears to be controlled in part by a complex series of interactions of oxysterol ligands with various receptors, such as the oxysterol binding protein, the cellular nucleic acid binding protein, the sterol regulatory element binding protein, the LXR nuclear orphan receptors, and the low-density lipoprotein receptor. Identification of the endogenous oxysterol ligands and elucidation of their enzymatic origins are topics of active investigation. Except for 24, 25-epoxysterols, most oxysterols arise from cholesterol by autoxidation or by specific microsomal or mitochondrial oxidations, usually involving cytochrome P-450 species. Oxysterols are variously metabolized to esters, bile acids, steroid hormones, cholesterol, or other sterols through pathways that may differ according to the type of cell and mode of experimentation (in vitro, in vivo, cell culture). Reliable measurements of oxysterol levels and activities are hampered by low physiological concentrations (approximately 0.01-0.1 microM plasma) relative to cholesterol (approximately 5,000 microM) and by the susceptibility of cholesterol to autoxidation, which produces artifactual oxysterols that may also have potent activities. Reports describing the occurrence and levels of oxysterols in plasma, low-density lipoproteins, various tissues, and food products include many unrealistic data resulting from inattention to autoxidation and to limitations of the analytical methodology. Because of the widespread lack of appreciation for the technical difficulties involved in oxysterol research, a rigorous evaluation of the chromatographic and spectroscopic methods used in the isolation, characterization, and quantitation of oxysterols has been included. This review comprises a detailed and critical assessment of current knowledge regarding the formation, occurrence, metabolism, regulatory properties, and other activities of oxysterols in mammalian systems.
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Affiliation(s)
- G J Schroepfer
- Departments of Biochemistry, Rice University, Houston, Texas, USA.
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