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Anajirih N, O'Sullivan SE, Alexander SP. Endocannabinoid hydrolases differentially distribute in platelets and red blood cells and are differentially released by thrombin. Prostaglandins Other Lipid Mediat 2023; 164:106692. [PMID: 36372184 DOI: 10.1016/j.prostaglandins.2022.106692] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 09/29/2022] [Accepted: 11/02/2022] [Indexed: 11/13/2022]
Abstract
BACKGROUND Plasma levels of the major endocannabinoids 2-arachidonoylgycerol (2AG) and anandamide (N-arachidonoylethanolamine, AEA) have been identified to vary independently with particular pathological conditions. The levels of these endocannabinoids are tightly regulated by two hydrolytic enzymes, monoacylglycerol lipase (MAGL) and fatty acid amide hydrolase (FAAH), respectively. OBJECTIVES In this study, we have quantified these enzyme activities in the major blood fractions. PATIENTS/METHODS In blood fractions from human volunteers, radiometric assays were used to quantify monoacylglycerol lipase and fatty acid amide hydrolase. Tagging with fluorophosphonate-rhodamine allowed quantification of platelet serine hydrolase activities. RESULTS Fatty acid amide hydrolase activity was highest in platelets, while MAGL activity was most abundant in erythrocytes. Sampling the blood of donors on two further occasions 15 days apart showed no significant change in platelet FAAH or erythrocyte MAGL activities. Activities were not different when comparing female donors with males. Storage of these blood fractions at - 80 °C was associated with a rapid loss in enzyme activities, which could largely by avoided by storage in liquid nitrogen. Incubation of platelets and erythrocytes in the presence of thrombin lead to release of measurable FAAH, but not MAGL, activity. Tagging of serine hydrolase activities with fluorophosphonate-rhodamine allowed confirmation of MAGL activity in platelet preparations, as well as multiple other enzymes. CONCLUSIONS These investigations suggest a potential role for FAAH in regulation of coagulation, while the role of MAGL in blood requires further investigation.
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Affiliation(s)
- Nuha Anajirih
- Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, University of Nottingham Medical School, Nottingham NG7 2UH, UK.
| | - Saoirse E O'Sullivan
- Division of Medical Sciences and Graduate Entry Medicine, School of Medicine, Royal Derby Hospital, University of Nottingham, Nottingham, UK.
| | - Stephen Ph Alexander
- Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, University of Nottingham Medical School, Nottingham NG7 2UH, UK.
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Miralpeix C, Reguera AC, Fosch A, Casas M, Lillo J, Navarro G, Franco R, Casas J, Alexander SPH, Casals N, Rodríguez-Rodríguez R. Carnitine palmitoyltransferase 1C negatively regulates the endocannabinoid hydrolase ABHD6 in mice, depending on nutritional status. Br J Pharmacol 2021; 178:1507-1523. [PMID: 33444462 PMCID: PMC9328656 DOI: 10.1111/bph.15377] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 11/09/2020] [Accepted: 11/13/2020] [Indexed: 01/05/2023] Open
Abstract
Background and Purpose The enzyme α/β‐hydrolase domain containing 6 (ABHD6), a new member of the endocannabinoid system, is a promising therapeutic target against neuronal‐related diseases. However, how ABHD6 activity is regulated is not known. ABHD6 coexists in protein complexes with the brain‐specific carnitine palmitoyltransferase 1C (CPT1C). CPT1C is involved in neuro‐metabolic functions, depending on brain malonyl–CoA levels. Our aim was to study CPT1C–ABHD6 interaction and determine whether CPT1C is a key regulator of ABHD6 activity depending on nutritional status. Experimental Approach Co‐immunoprecipitation and FRET assays were used to explore ABHD6 interaction with CPT1C or modified malonyl–CoA‐insensitive or C‐terminal truncated CPT1C forms. Cannabinoid CB1 receptor‐mediated signalling was investigated by determining cAMP levels. A novel highly sensitive fluorescent method was optimized to measure ABHD6 activity in non‐neuronal and neuronal cells and in brain tissues from wild‐type (WT) and CPT1C–KO mice. Key Results CPT1C interacted with ABHD6 and negatively regulated its hydrolase activity, thereby regulating 2‐AG downstream signalling. Accordingly, brain tissues of CPT1C–KO mice showed increased ABHD6 activity. CPT1C malonyl–CoA sensing was key to the regulatory role on ABHD6 activity and CB1 receptor signalling. Fasting, which attenuates brain malonyl–CoA, significantly increased ABHD6 activity in hypothalamus from WT, but not CPT1C–KO, mice. Conclusions and Implications Our finding that negative regulation of ABHD6 activity, particularly in the hypothalamus, is sensitive to nutritional status throws new light on the characterization and the importance of the proteins involved as potential targets against diseases affecting the CNS.
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Affiliation(s)
- Cristina Miralpeix
- Basic Sciences Department, Faculty of Medicine and Health Sciences, Universitat Internacional de Catalunya, Sant Cugat del Vallès, Spain.,INSERM, Neurocentre Magendie, University of Bordeaux, Bordeaux, France
| | - Ana Cristina Reguera
- Basic Sciences Department, Faculty of Medicine and Health Sciences, Universitat Internacional de Catalunya, Sant Cugat del Vallès, Spain
| | - Anna Fosch
- Basic Sciences Department, Faculty of Medicine and Health Sciences, Universitat Internacional de Catalunya, Sant Cugat del Vallès, Spain
| | - Maria Casas
- Basic Sciences Department, Faculty of Medicine and Health Sciences, Universitat Internacional de Catalunya, Sant Cugat del Vallès, Spain.,Department of Physiology and Membrane Biology, University of California, Davis, Davis, California, USA
| | - Jaume Lillo
- Molecular Neurobiology Laboratory, Department of Biochemistry and Physiology, Faculty of Biology, University of Barcelona, Barcelona, Spain
| | - Gemma Navarro
- INSERM, Neurocentre Magendie, University of Bordeaux, Bordeaux, France
| | - Rafael Franco
- INSERM, Neurocentre Magendie, University of Bordeaux, Bordeaux, France
| | - Josefina Casas
- Department on Biomedical Chemistry, Research Unit of BioActive Molecules, Institut de Química Avançada de Catalunya (IQAC), Barcelona, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBEREHD), Instituto de Salud Carlos III, Madrid, Spain
| | | | - Núria Casals
- Basic Sciences Department, Faculty of Medicine and Health Sciences, Universitat Internacional de Catalunya, Sant Cugat del Vallès, Spain.,Centro de Investigación Biomédica en Red de Fisiopatología de la Obesidad y la Nutrición (CIBEROBN), Instituto de Salud Carlos III, Madrid, Spain
| | - Rosalía Rodríguez-Rodríguez
- Basic Sciences Department, Faculty of Medicine and Health Sciences, Universitat Internacional de Catalunya, Sant Cugat del Vallès, Spain
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3
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Kim RJ, Kim HJ, Shim D, Suh MC. Molecular and biochemical characterizations of the monoacylglycerol lipase gene family of Arabidopsis thaliana. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2016; 85:758-71. [PMID: 26932457 DOI: 10.1111/tpj.13146] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Revised: 02/09/2016] [Accepted: 02/15/2016] [Indexed: 05/23/2023]
Abstract
Monoacylglycerol lipase (MAGL) catalyzes the last step of triacylglycerol breakdown, which is the hydrolysis of monoacylglycerol (MAG) to fatty acid and glycerol. Arabidopsis harbors over 270 genes annotated as 'lipase', the largest class of acyl lipid metabolism genes that have not been characterized experimentally. In this study, computational modeling suggested that 16 Arabidopsis putative MAGLs (AtMAGLs) have a three-dimensional structure that is similar to a human MAGL. Heterologous expression and enzyme assays indicated that 11 of the 16 encoded proteins indeed possess MAG lipase activity. Additionally, AtMAGL4 displayed hydrolase activity with lysophosphatidylcholine and lysophosphatidylethanolamine (LPE) substrates and AtMAGL1 and 2 utilized LPE as a substrate. All recombinant AtMAGLs preferred MAG substrates with unsaturated fatty acids over saturated fatty acids and AtMAGL8 exhibited the highest hydrolase activities with MAG containing 20:1 fatty acids. Except for AtMAGL4, -14 and -16, all AtMAGLs showed similar activity with both sn-1 and sn-2 MAG isomers. Spatial, temporal and stress-induced expression of the 16 AtMAGL genes was analyzed by transcriptome analyses. AtMAGL:eYFP fusion proteins provided initial evidence that AtMAGL1, -3, -6, -7, -8, -11, -13, -14 and -16 are targeted to the endoplasmic reticulum and/or Golgi network, AtMAGL10, -12 and -15 to the cytosol and AtMAGL2, -4 and -5 to the chloroplasts. Furthermore, AtMAGL8 was associated with the surface of oil bodies in germinating seeds and leaves accumulating oil bodies. This study provides the broad characterization of one of the least well-understood groups of Arabidopsis lipid-related enzymes and will be useful for better understanding their roles in planta.
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Affiliation(s)
- Ryeo Jin Kim
- Department of Bioenergy Science and Technology, Chonnam National University, Gwangju, 500-757, Korea
| | - Hae Jin Kim
- Department of Bioenergy Science and Technology, Chonnam National University, Gwangju, 500-757, Korea
| | - Donghwan Shim
- Department of Bioenergy Science and Technology, Chonnam National University, Gwangju, 500-757, Korea
| | - Mi Chung Suh
- Department of Bioenergy Science and Technology, Chonnam National University, Gwangju, 500-757, Korea
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4
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Navia-Paldanius D, Savinainen JR, Laitinen JT. Biochemical and pharmacological characterization of human α/β-hydrolase domain containing 6 (ABHD6) and 12 (ABHD12). J Lipid Res 2012; 53:2413-24. [PMID: 22969151 DOI: 10.1194/jlr.m030411] [Citation(s) in RCA: 126] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
In the central nervous system, three enzymes belonging to the serine hydrolase family are thought to regulate the life time of the endocannabinoid 2-arachidonoylglycerol (C20:4) (2-AG). From these, monoacylglycerol lipase (MAGL) is well characterized and, on a quantitative basis, is the main 2-AG hydrolase. The postgenomic proteins α/β-hydrolase domain containing (ABHD)6 and ABHD12 remain poorly characterized. By applying a sensitive fluorescent glycerol assay, we delineate the substrate preferences of human ABHD6 and ABHD12 in comparison with MAGL. We show that the three hydrolases are genuine MAG lipases; medium-chain saturated MAGs were the best substrates for hABHD6 and hMAGL, whereas hABHD12 preferred the 1 (3)- and 2-isomers of arachidonoylglycerol. Site-directed mutagenesis of the amino acid residues forming the postulated catalytic triad (ABHD6: S148-D278-H306, ABHD12: S246-D333-H372) abolished enzymatic activity as well as labeling with the active site serine-directed fluorophosphonate probe TAMRA-FP. However, the role of D278 and H306 as residues of the catalytic core of ABHD6 could not be verified because none of the mutants showed detectable expression. Inhibitor profiling revealed striking potency differences between hABHD6 and hABHD12, a finding that, when combined with the substrate profiling data, should facilitate further efforts toward the design of potent and selective inhibitors, especially those targeting hABHD12, which currently lacks such inhibitors.
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Affiliation(s)
- Dina Navia-Paldanius
- Institute of Biomedicine, School of Medicine, University of Eastern Finland, Kuopio Campus, Kuopio, Finland
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5
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Abstract
Lipases are ubiquitous enzymes, widespread in nature. They were first isolated from bacteria in the early nineteenth century and the associated research continuously increased due to the particular characteristics of these enzymes. This chapter reviews the main sources, structural properties, and industrial applications of these highly studied enzymes.
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Affiliation(s)
- Leticia Casas-Godoy
- Equipe de Catalyse et Ingénierie Moléculaire Enzymatique, Laboratoire d'Ingénierie des Systèmes Biologiques et Procédés, Université de Toulouse, INSA, UPS, INP, LISBP, Toulouse, France
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6
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Schalk-Hihi C, Schubert C, Alexander R, Bayoumy S, Clemente JC, Deckman I, DesJarlais RL, Dzordzorme KC, Flores CM, Grasberger B, Kranz JK, Lewandowski F, Liu L, Ma H, Maguire D, Macielag MJ, McDonnell ME, Mezzasalma Haarlander T, Miller R, Milligan C, Reynolds C, Kuo LC. Crystal structure of a soluble form of human monoglyceride lipase in complex with an inhibitor at 1.35 Å resolution. Protein Sci 2011; 20:670-83. [PMID: 21308848 PMCID: PMC3081545 DOI: 10.1002/pro.596] [Citation(s) in RCA: 97] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2010] [Accepted: 01/14/2011] [Indexed: 01/07/2023]
Abstract
A high-resolution structure of a ligand-bound, soluble form of human monoglyceride lipase (MGL) is presented. The structure highlights a novel conformation of the regulatory lid-domain present in the lipase family as well as the binding mode of a pharmaceutically relevant reversible inhibitor. Analysis of the structure lacking the inhibitor indicates that the closed conformation can accommodate the native substrate 2-arachidonoyl glycerol. A model is proposed in which MGL undergoes conformational and electrostatic changes during the catalytic cycle ultimately resulting in its dissociation from the membrane upon completion of the cycle. In addition, the study outlines a successful approach to transform membrane associated proteins, which tend to aggregate upon purification, into a monomeric and soluble form.
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Affiliation(s)
- Céline Schalk-Hihi
- Department of Structural Biology, Johnson & Johnson Pharmaceutical Research and DevelopmentL.L.C., Welsh and McKean Roads, Spring House, Pennsylvania 19477,*Correspondence to: Céline Schalk-Hihi (E-mail: ) or Carsten Schubert (E-mail: )
| | - Carsten Schubert
- Department of Structural Biology, Johnson & Johnson Pharmaceutical Research and DevelopmentL.L.C., Welsh and McKean Roads, Spring House, Pennsylvania 19477,*Correspondence to: Céline Schalk-Hihi (E-mail: ) or Carsten Schubert (E-mail: )
| | - Richard Alexander
- Department of Structural Biology, Johnson & Johnson Pharmaceutical Research and DevelopmentL.L.C., Welsh and McKean Roads, Spring House, Pennsylvania 19477
| | - Shariff Bayoumy
- Department of Structural Biology, Johnson & Johnson Pharmaceutical Research and DevelopmentL.L.C., Welsh and McKean Roads, Spring House, Pennsylvania 19477
| | - Jose C Clemente
- Department of Lead Generation Biology, Johnson & Johnson Pharmaceutical Research and DevelopmentL.L.C., Welsh and McKean Roads, Spring House, Pennsylvania 19477
| | - Ingrid Deckman
- Department of Lead Generation Biology, Johnson & Johnson Pharmaceutical Research and DevelopmentL.L.C., Welsh and McKean Roads, Spring House, Pennsylvania 19477
| | - Renee L DesJarlais
- Department of Structural Biology, Johnson & Johnson Pharmaceutical Research and DevelopmentL.L.C., Welsh and McKean Roads, Spring House, Pennsylvania 19477
| | - Keli C Dzordzorme
- Department of Structural Biology, Johnson & Johnson Pharmaceutical Research and DevelopmentL.L.C., Welsh and McKean Roads, Spring House, Pennsylvania 19477
| | - Christopher M Flores
- Department of Neuroscience, Johnson & Johnson Pharmaceutical Research and DevelopmentL.L.C., Welsh and McKean Roads, Spring House, Pennsylvania 19477
| | - Bruce Grasberger
- Department of Structural Biology, Johnson & Johnson Pharmaceutical Research and DevelopmentL.L.C., Welsh and McKean Roads, Spring House, Pennsylvania 19477
| | - James K Kranz
- Department of Lead Generation Biology, Johnson & Johnson Pharmaceutical Research and DevelopmentL.L.C., Welsh and McKean Roads, Spring House, Pennsylvania 19477
| | - Frank Lewandowski
- Department of Structural Biology, Johnson & Johnson Pharmaceutical Research and DevelopmentL.L.C., Welsh and McKean Roads, Spring House, Pennsylvania 19477
| | - Li Liu
- Department of Medicinal Chemistry, Johnson & Johnson Pharmaceutical Research and DevelopmentL.L.C., Welsh and McKean Roads, Spring House, Pennsylvania 19477
| | - Hongchang Ma
- Department of Structural Biology, Johnson & Johnson Pharmaceutical Research and DevelopmentL.L.C., Welsh and McKean Roads, Spring House, Pennsylvania 19477
| | - Diane Maguire
- Department of Structural Biology, Johnson & Johnson Pharmaceutical Research and DevelopmentL.L.C., Welsh and McKean Roads, Spring House, Pennsylvania 19477
| | - Mark J Macielag
- Department of Medicinal Chemistry, Johnson & Johnson Pharmaceutical Research and DevelopmentL.L.C., Welsh and McKean Roads, Spring House, Pennsylvania 19477
| | - Mark E McDonnell
- Department of Medicinal Chemistry, Johnson & Johnson Pharmaceutical Research and DevelopmentL.L.C., Welsh and McKean Roads, Spring House, Pennsylvania 19477
| | - Tara Mezzasalma Haarlander
- Department of Lead Generation Biology, Johnson & Johnson Pharmaceutical Research and DevelopmentL.L.C., Welsh and McKean Roads, Spring House, Pennsylvania 19477
| | - Robyn Miller
- Department of Structural Biology, Johnson & Johnson Pharmaceutical Research and DevelopmentL.L.C., Welsh and McKean Roads, Spring House, Pennsylvania 19477
| | - Cindy Milligan
- Department of Structural Biology, Johnson & Johnson Pharmaceutical Research and DevelopmentL.L.C., Welsh and McKean Roads, Spring House, Pennsylvania 19477
| | - Charles Reynolds
- Department of Structural Biology, Johnson & Johnson Pharmaceutical Research and DevelopmentL.L.C., Welsh and McKean Roads, Spring House, Pennsylvania 19477
| | - Lawrence C Kuo
- Department of Structural Biology, Johnson & Johnson Pharmaceutical Research and DevelopmentL.L.C., Welsh and McKean Roads, Spring House, Pennsylvania 19477
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8
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Ecto-lysophospholipase C controls lysophospholipid uptake and metabolism in porcine kidney epithelial cell line LLC-PK1. Prostaglandins Other Lipid Mediat 2009; 88:1-9. [DOI: 10.1016/j.prostaglandins.2008.08.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2008] [Revised: 08/07/2008] [Accepted: 08/11/2008] [Indexed: 10/21/2022]
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9
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Stella N. Endocannabinoid signaling in microglial cells. Neuropharmacology 2008; 56 Suppl 1:244-53. [PMID: 18722389 DOI: 10.1016/j.neuropharm.2008.07.037] [Citation(s) in RCA: 193] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2008] [Revised: 07/21/2008] [Accepted: 07/28/2008] [Indexed: 11/26/2022]
Abstract
The endocannabinoid signaling system (eCBSS) is composed of cannabinoid (CB) receptors, their endogenous ligands (the endocannabinoids, eCB) and the enzymes that produce and inactivate these ligands. Neurons use this signaling system to communicate with each other and Delta9-tetrahydrocannabinol (THC), the main psychotropic ingredient of Cannabis sativa, induces profound behavioral effects by impinging on this communication. Evidence now shows that microglia, the macrophages of the brain, also express a functional eCBSS and that activation of CB receptors expressed by activated microglia controls their immune-related functions. This review summarizes this evidence, discusses how microglia might use the eCBSS to communicate with each other and neighboring cells, and argues that compounds selectively targeting the eCBSS expressed by microglia constitute valuable therapeutics to manage acute and chronic neuroinflammation, without inducing the psychotropic effects and underlying addictive properties commonly associated with THC.
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Affiliation(s)
- Nephi Stella
- Department of Pharmacology, Psychiatry and Behavioral Sciences, 1959 NE Pacific Street, University of Washington, Seattle, WA 98195-7280, USA.
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10
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Côtes K, Dhouib R, Douchet I, Chahinian H, deCaro A, Carrière F, Canaan S. Characterization of an exported monoglyceride lipase from Mycobacterium tuberculosis possibly involved in the metabolism of host cell membrane lipids. Biochem J 2008; 408:417-27. [PMID: 17784850 PMCID: PMC2267359 DOI: 10.1042/bj20070745] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The Rv0183 gene of the Mycobacterium tuberculosis H37Rv strain, which has been implicated as a lysophospholipase, was cloned and expressed in Escherichia coli. The purified Rv0183 protein did not show any activity when lysophospholipid substrates were used, but preferentially hydrolysed monoacylglycerol substrates with a specific activity of 290 units x mg(-1) at 37 degrees C. Rv0183 hydrolyses both long chain di- and triacylglycerols, as determined using the monomolecular film technique, although the turnover was lower than with MAG (monoacyl-glycerol). The enzyme shows an optimum activity at pH values ranging from 7.5 to 9.0 using mono-olein as substrate and is inactivated by serine esterase inhibitors such as E600, PMSF and tetrahydrolipstatin. The catalytic triad is composed of Ser110, Asp226 and His256 residues, as confirmed by the results of site-directed mutagenesis. Rv0183 shows 35% sequence identity with the human and mouse monoglyceride lipases and well below 15% with the other bacterial lipases characterized so far. Homologues of Rv0183 can be identified in other mycobacterial genomes such as Mycobacterium bovis, Mycobacterium smegmatis, and even Mycobacterium leprae, which is known to contain a low number of genes involved in the replication process within the host cells. The results of immunolocalization studies performed with polyclonal antibodies raised against the purified recombinant Rv0183 suggested that the enzyme was present only in the cell wall and culture medium of M. tuberculosis. Our results identify Rv0183 as the first exported lipolytic enzyme to be characterized in M. tuberculosis and suggest that Rv0183 may be involved in the degradation of the host cell lipids.
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Affiliation(s)
- Karen Côtes
- Laboratoire d'Enzymologie Interfaciale et de Physiologie de la Lipolyse, UPR 9025 - CNRS, 31 Chemin Joseph Aiguier, F-13402 Marseille Cedex 20, France
| | - Rabeb Dhouib
- Laboratoire d'Enzymologie Interfaciale et de Physiologie de la Lipolyse, UPR 9025 - CNRS, 31 Chemin Joseph Aiguier, F-13402 Marseille Cedex 20, France
| | - Isabelle Douchet
- Laboratoire d'Enzymologie Interfaciale et de Physiologie de la Lipolyse, UPR 9025 - CNRS, 31 Chemin Joseph Aiguier, F-13402 Marseille Cedex 20, France
| | - Henri Chahinian
- Laboratoire d'Enzymologie Interfaciale et de Physiologie de la Lipolyse, UPR 9025 - CNRS, 31 Chemin Joseph Aiguier, F-13402 Marseille Cedex 20, France
| | - Alain deCaro
- Laboratoire d'Enzymologie Interfaciale et de Physiologie de la Lipolyse, UPR 9025 - CNRS, 31 Chemin Joseph Aiguier, F-13402 Marseille Cedex 20, France
| | - Frédéric Carrière
- Laboratoire d'Enzymologie Interfaciale et de Physiologie de la Lipolyse, UPR 9025 - CNRS, 31 Chemin Joseph Aiguier, F-13402 Marseille Cedex 20, France
| | - Stéphane Canaan
- Laboratoire d'Enzymologie Interfaciale et de Physiologie de la Lipolyse, UPR 9025 - CNRS, 31 Chemin Joseph Aiguier, F-13402 Marseille Cedex 20, France
- To whom correspondence should be sent (email )
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11
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Saario SM, Laitinen JT. Monoglyceride lipase as an enzyme hydrolyzing 2-arachidonoylglycerol. Chem Biodivers 2007; 4:1903-13. [PMID: 17712832 DOI: 10.1002/cbdv.200790158] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Susanna M Saario
- Department of Pharmaceutical Chemistry, University of Kuopio, P.O. Box 1627, FI-70211 Kuopio.
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12
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Muccioli GG, Xu C, Odah E, Cudaback E, Cisneros JA, Lambert DM, López Rodríguez ML, Bajjalieh S, Stella N. Identification of a novel endocannabinoid-hydrolyzing enzyme expressed by microglial cells. J Neurosci 2007; 27:2883-9. [PMID: 17360910 PMCID: PMC6672592 DOI: 10.1523/jneurosci.4830-06.2007] [Citation(s) in RCA: 141] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The endocannabinoids (eCBs) anandamide and 2-arachidonoyl glycerol (2-AG) are inactivated by a two-step mechanism. First, they are carried into cells, and then anandamide is hydrolyzed by fatty acid amide hydrolase (FAAH) and 2-AG by monoacylglycerol lipase (MGL). Here we provide evidence for a previously undescribed MGL activity expressed by microglial cells. We found that the mouse microglial cell line BV-2 does not express MGL mRNA and yet efficiently hydrolyzes 2-AG. URB597 (3'-carbamoyl-biphenyl-3-yl-cyclohexylcarbamate) reduces this hydrolysis by 50%, suggesting the involvement of FAAH. The remaining activity is blocked by classic MGL inhibitors [[1,1-biphenyl]-3-yl-carbamic acid, cyclohexyl ester (URB602) and MAFP (methylarachidonyl fluorophosphate)] and is unaffected by inhibitors of COXs (cyclooxygenases), LOXs (lipooxygenases), and DGLs (diacylglycerol lipases), indicating the involvement of a novel MGL activity. Accordingly, URB602 leads to selective accumulation of 2-AG in intact BV-2 cells. Although MGL expressed in neurons is equally distributed between the cytosolic, mitochondrial, and nuclear fractions, the novel MGL activity expressed by BV-2 cells is enriched in mitochondrial and nuclear fractions. A screen for novel inhibitors of eCB hydrolysis identified several compounds that differentially block MGL, FAAH, and the novel MGL activity. Finally, we provide evidence for expression of the novel MGL by mouse primary microglia in culture. Our results suggest the presence of a novel, pharmacologically distinct, MGL activity that controls 2-AG levels in microglia.
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Affiliation(s)
| | - Cong Xu
- Departments of Pharmacology and
| | | | | | - Jose Antonio Cisneros
- Departamento de Quimica Organica I, Facultad de Ciencias Quimicas, Universidad Complutense, E-28040 Madrid, Spain, and
| | - Didier M. Lambert
- Drug Design and Discovery Center and Unité de Chimie Pharmaceutique et de Radiopharmacie, Université catholique de Louvain, B-1200 Brussels, Belgium
| | - María Luz López Rodríguez
- Departamento de Quimica Organica I, Facultad de Ciencias Quimicas, Universidad Complutense, E-28040 Madrid, Spain, and
| | | | - Nephi Stella
- Departments of Pharmacology and
- Psychiatry and Behavioral Sciences, University of Washington, Seattle, Washington 98195-7280
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13
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Ho WSV, Hillard CJ. Modulators of endocannabinoid enzymic hydrolysis and membrane transport. Handb Exp Pharmacol 2005:187-207. [PMID: 16596775 DOI: 10.1007/3-540-26573-2_6] [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: 12/26/2022]
Abstract
Tissue concentrations of the endocannabinoids N-arachidonoylethanolamine (AEA) and 2-arachidonoylglycerol (2-AG) are regulated by both synthesis and inactivation. The purpose of this review is to compile available data regarding three inactivation processes: fatty acid amide hydrolase, monoacylglycerol lipase, and cellular membrane transport. In particular, we have focused on mechanisms by which these processes are modulated. We describe the in vitro and in vivo effects of inhibitors of these processes as well as available evidence regarding their modulation by other factors.
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Affiliation(s)
- W S V Ho
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA
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14
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Ghafouri N, Tiger G, Razdan RK, Mahadevan A, Pertwee RG, Martin BR, Fowler CJ. Inhibition of monoacylglycerol lipase and fatty acid amide hydrolase by analogues of 2-arachidonoylglycerol. Br J Pharmacol 2004; 143:774-84. [PMID: 15492019 PMCID: PMC1575926 DOI: 10.1038/sj.bjp.0705948] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The pharmacology of monoacylglycerol lipase (MAGL) is not well understood. In consequence, the abilities of a series of analogues of 2-arachidonoylglycerol (2-AG) to inhibit cytosolic 2-oleoylglycerol and membrane-bound anandamide hydolysis by MAGL and fatty acid amide hydrolase (FAAH), respectively, have been investigated. 2-AG and its 1-regioisomer (1-AG) interacted with MAGL with similar affinities (IC(50) values 13 and 17 mum, respectively). Shorter homologues of 2-AG (2-linoleoylglycerol and 2-oleoylglycerol) had affinities for MAGL similar to 2-AG. This pattern was also seen when the arachidonoyl side chain of arachidonoyl trifluoromethylketone was replaced by an oleoyl side chain. Arachidonoyl serinol (IC(50) value 73 microM) was a weaker inhibitor of MAGL than 2-AG. The IC(50) values of noladin ether towards MAGL and FAAH were 36 and 3 microM, respectively. Arachidonoyl glycine interacted with FAAH (IC(50) value 4.9 microM) but only weakly interacted with MAGL (IC(50) value >100 microM). alpha-Methyl-1-AG had similar potencies towards MAGL and FAAH (IC(50) values of 11 and 33 microM, respectively). O-2203 (1-(20-cyano-16,16-dimethyl-eicosa-5,8,11,14-tetraenoyl) glycerol) and O-2204 (2-(20-hydroxy-16,16-dimethyl-eicosa-5,8,11,14-tetraenoyl) glycerol) were slightly less potent, but again affected both enzymes equally. alpha-Methyl-1-AG, O-2203 and O-2204 interacted only weakly with cannabinoid CB(1) receptors expressed in CHO cells (K(i) values 1.8, 3.7 and 3.2 microM, respectively, compared with 0.24 microM for 1-AG) and showed no evidence of central cannabinoid receptor activation in vivo at doses up to 30 mg kg(-1) i.v. It is concluded that compounds like alpha-Methyl-1-AG, O-2203 and O-2204 may be useful as leads for the discovery of selective MAGL inhibitors that lack direct effects upon cannabinoid receptors.
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Affiliation(s)
- Nazdar Ghafouri
- Department of Pharmacology and Clinical Neuroscience, Umeå University, SE-901 87 Umeå, Sweden
| | - Gunnar Tiger
- Department of Pharmacology and Clinical Neuroscience, Umeå University, SE-901 87 Umeå, Sweden
| | | | | | - Roger G Pertwee
- School of Medical Sciences, University of Aberdeen, Aberdeen AB25 2ZD
| | - Billy R Martin
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA, U.S.A
| | - Christopher J Fowler
- Department of Pharmacology and Clinical Neuroscience, Umeå University, SE-901 87 Umeå, Sweden
- Author for correspondence:
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15
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Sakiyama T, Yoshimi T, Miyake A, Umeoka M, Tanaka A, Ozaki S, Nakanishi K. Purification and characterization of a monoacylglycerol lipase from Pseudomonas sp. LP7315. J Biosci Bioeng 2001. [DOI: 10.1016/s1389-1723(01)80106-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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16
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Sakiyama T, Yoshimi T, Miyake A, Umeoka M, Tanaka A, Ozaki S, Nakanishi K. Purification and Characterization of a Monoacylglycerol Lipase from Pseudomonas sp. LP7315. J Biosci Bioeng 2001; 91:27-32. [PMID: 16232941 DOI: 10.1263/jbb.91.27] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2000] [Accepted: 10/10/2000] [Indexed: 11/17/2022]
Abstract
A monoacylglycerol lipase (MGL) was purified from Pseudomonas sp. LP7315 by ammonium sulfate precipitation, anion-exchange chromatography, and preparative electrophoresis. The purified enzyme was homogeneous on SDS-PAGE with a molecular mass of 59 kDa. Its hydrolytic activity was confirmed to be specific for monoglycerides: the enzyme did not hydrolyze di- and triglycerides. MGL was found to be stable even after 1-h incubation at 65 degrees C. The optimum pH for monopalmitin hydrolysis was approximately 8. The hydrolytic activity depended not only on temperature and pH but also on the type of monoglyceride used. MGL also catalyzed monoglyceride synthesis at 65 degrees C in a solvent-free two-phase system, in which fatty acid droplets were dispersed in the glycerol phase with a low water content. The synthetic reaction proceeded at a constant rate for approximately 24 h and approximately reached an equilibrium after 48 h of reaction. The initial rate and equilibrium yield of the synthetic reaction depended on the type of fatty acid used as the substrate.
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Affiliation(s)
- T Sakiyama
- Department of Bioscience and Biotechnology, Faculty of Engineering, Okayama University, 3-1-1 Tsushima-naka, Okayama 700-8530, Japan
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17
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Waterman IJ, Emmison N, Sattar N, Dutta-Roy AK. Further characterization of a novel triacylglycerol hydrolase activity (pH 6.0 optimum) from microvillous membranes from human term placenta. Placenta 2000; 21:813-23. [PMID: 11095931 DOI: 10.1053/plac.2000.0572] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
We recently identified the presence of two distinct triacylglycerol hydrolases with pH optima of 6.0 and 8.0 in human placental microvillous membranes (MVM). The TAG hydrolase with a pH optimum of 8.0 has properties similar to lipoprotein lipase, whereas TAG hydrolase with a pH optimum of 6.0 still to be fully characterized. In order to understand the functional and structural relationships between these two TAG hydrolases of MVM we have further investigated their biochemical and molecular properties. The presence of oleic acid inhibited TAG hydrolase activity with a pH optimum of 8.0 by 60 per cent whilst it had very little effect on the pH 6.0 TAG hydrolase activity. K(m)values for TAG hydrolases at pH 6.0 and pH 8. 0 optima were 170.6 and 9.83 nmol triolein, respectively, whereas the corresponding V(max)values were 0.32 and 0.037 nmol oleic acid/min mg/protein. Treatment of MVM with phenylmethylsulphonofluoride or protamine had no effect on TAG hydrolase at pH 6.0 whereas both decreased activity at pH 8.0, by 70 per cent and 52 per cent, respectively (P< 0.05), compared with control. p-Chloromercuribenzoate inhibited both TAG hydrolase activities by 25-30 per cent whereas iodoacetate inhibited TAG hydrolase activity with optimum pH 8.0 by 74 per cent and the activity at pH 6.0 by 28 per cent. Unlike the TAG hydrolase activity at pH 8.0, the activity at pH 6.0 was not affected by heparin. TAG hydrolase activity at pH 6.0 was significantly decreased compared with that of pH 8.0 optimum TAG hydrolase activity in smokers placenta. A threefold increase in pH 6.0 TAG hydrolase activity was observed following differentiation, whereas membrane associated TAG hydrolase activity with optimum pH 8.0 did not change. The TAG hydrolase with optimum pH 6.0 was subsequently purified from MVM to almost 1000-fold enrichment of the activity over the starting material. The final preparation however, still contained three distinct protein bands (90, 70 and 45 kDa). When extracted from non-denaturing polyacrylamide gels, the 70 kDa protein was the only protein to have TAG hydrolysing activity and had a pH optimum of 6.0. Labelling of samples with [(14)C]tetrahydrolipstatin also confirmed that the TAG hydrolase active protein was a 70 kDa protein. In conclusion, we report that there is a 70 kDa TAG hydrolase with optimum pH 6.0 in human placental MVM which is quite distinct from placental lipoprotein lipase.
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Affiliation(s)
- I J Waterman
- Rowett Research Institute, Aberdeen, AB21 9SB, UK
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18
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Baker RR, Chang HY. A metabolic path for the degradation of lysophosphatidic acid, an inhibitor of lysophosphatidylcholine lysophospholipase, in neuronal nuclei of cerebral cortex. BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1483:58-68. [PMID: 10601695 DOI: 10.1016/s1388-1981(99)00185-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Neuronal nuclei isolated from rabbit cerebral cortex were found to be enriched in an NEM-insensitive lysophosphatidic acid (lysoPA) phosphohydrolase activity. LysoPA is an inhibitor of the nuclear lysophosphatidylcholine (lysoPC) lysophospholipase, and by preserving lysoPC levels, lysoPA boosted the nuclear production of the acyl analogue of platelet-activating factor by promoting the acetylation of lysoPC (Baker and Chang, Mol. Cell Biochem., 1999, in press). The nuclear phosphohydrolase converts lysoPA to 1-monoacylglycerol, and thus eliminates this lysoPA inhibition of lysoPC lysophospholipase. The nuclear lysoPA phosphohydrolase specific activity was more than three times that observed for the nuclear lysoPA lysophospholipase (Baker and Chang, Biochim. Biophys. Acta 1438 (1999) 253-263) and represents a more active route for nuclear lysoPA removal. The neuronal nuclear lysoPA phosphohydrolase was inhibited at acidic pH, and also inhibited by calcium ions. The 1-monoacylglycerol product of the phosphohydrolase is rapidly degraded by neuronal monoacylglycerol lipase, an enzyme some sevenfold more active than the phosphohydrolase and sensitive to inhibition by arachidonoyl trifluoromethyl ketone (AACOCF(3)). Both acidic pH and free fatty acid inhibited the lipase. In the absence of AACOCF(3), production of fatty acid from lysoPA substrate could be largely attributed to the sequential actions of the nuclear phosphohydrolase and lipase. This facilitates fatty acid recycling back into phospholipid by lysophospholipid acylation when ATP levels are restored following periods of brain ischemia. At relatively low concentrations, sphingosine-1-phosphate, and alkylglycerophosphate were the most effective phosphohydrolase inhibitors while phosphatidic acid, alkylacetylglycerophosphate and ceramide were without effect. LysoPA is an interesting regulatory molecule that can potentially preserve lysophosphatidylcholine within the nuclear membrane for use in acetylation reactions. Thus conditions relevant to brain ischemia such as falling pH, falling ATP concentrations, rising fatty acid and intracellular calcium levels may, by slowing this metabolic path for lysoPA loss, promote the production of acyl PAF and contribute to the increased levels of the acetylated lipids noted in ischemia.
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Affiliation(s)
- R R Baker
- Department of Biochemistry, Room 5202, Medical Sciences Bldg., University of Toronto, Toronto, Ont., Canada.
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19
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Vérine A, Bruneau N, Valette A, Le Petit-Thevenin J, Pasqualini E, Lombardo D. Immunodetection and molecular cloning of a bile-salt-dependent lipase isoform in HepG2 cells. Biochem J 1999; 342 ( Pt 1):179-87. [PMID: 10432315 PMCID: PMC1220451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
In this article, we report the nucleotide sequence of the cDNA encoding an isoform of bile-salt-dependent lipase (BSDL) expressed by human hepatoma cells. The BSDL is a 100-kDa glycoprotein normally expressed by the human pancreas. Using a polyclonal antibody raised against an internal peptide located between Ile(327) and Glu(350) of the human pancreatic BSDL, we have immunodetected an isoform of human pancreatic BSDL, with an apparent molecular mass of about 62 kDa. This isoform of BSDL was mainly associated with the cytosol of a human hepatoma cell line (HepG2), the remaining protein being found in the microsome fraction. In addition, esterolytic activity on p-nitrophenyl hexanoate measured in microsomes and cytosol appeared very low and was weakly stimulated by bile salts, such as taurocholate. In contrast to human pancreatic BSDL, which is secreted as a component of pancreatic juice, this isoform appeared to be retained in the HepG2 cells. Reverse transcription, followed by PCR and amplification, performed on RNA extracted from HepG2 cells using specific primers hybridizing to the sequence coding for the entire normal human pancreatic BSDL, allowed us to amplify a 1. 7-kb transcript that appeared to be 0.5 kb shorter than the transcript of the pancreatic enzyme (2.2 kb). From the sequence of the transcript thus obtained, a protein with a molecular mass of 62 kDa might be predicted, which is in good agreement with the size of the isoform of BSDL immunodetected in HepG2 cells. The N-terminal amino-acid sequence, deduced from the 1.7-kb transcript sequence, matched that of the pancreatic BSDL. However, the C-terminal domain appeared truncated, bearing only a single mucin-like sequence compared with sixteen for the human pancreatic BSDL. The actual intracellular function of this human BSDL hepatoma isoform remains to be elucidated.
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Affiliation(s)
- A Vérine
- INSERM U 260, Unité de Recherches de Physiopathologie des Régulations Hormono-Nutritionnelles, Faculté de Médecine, 27 Bld Jean Moulin, 13385 Marseille Cedex 05, France.
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20
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Di Marzo V, Bisogno T, De Petrocellis L, Melck D, Orlando P, Wagner JA, Kunos G. Biosynthesis and inactivation of the endocannabinoid 2-arachidonoylglycerol in circulating and tumoral macrophages. EUROPEAN JOURNAL OF BIOCHEMISTRY 1999; 264:258-67. [PMID: 10447696 DOI: 10.1046/j.1432-1327.1999.00631.x] [Citation(s) in RCA: 243] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The stimulus-induced biosynthesis of the endocannabinoid 2-arachidonoylglycerol (2-AG) in intact mouse J774 macrophages and the inactivation of 2-AG by the same cells or by rat circulating macrophages was studied. By using gas chromatography-mass spectrometry, we found that ionomycin (5 microM) and lipopolysaccharide (LPS, 200 microg x mL-1) cause a 24-fold and 2.5-fold stimulation of 2-AG levels in J774 cells, respectively, thus providing unprecedented evidence that this cannabimimetic metabolite can be synthesized by macrophages. In J774 cells, LPS also induced a 7.8-fold increase of the levels of the other endocannabinoid, anandamide, and, in rat circulating macrophages, an almost twofold increase of 2-AG levels. Extracellular [3H]2-AG was cleared from the medium of intact J774 macrophages (t1/2 = 19-28 min) and esterified to phospholipids, diacylglycerols and triglycerides or hydrolyzed to [3H]arachidonic acid and glycerol. These catabolic processes were attenuated differentially by various enzyme inhibitors. Rat circulating macrophages were shown to contain enzymatic activities for the hydrolysis of 2-AG, including: (a) fatty acid amide hydrolase (FAAH), the enzyme responsible for anandamide breakdown and previously shown to catalyse also 2-AG hydrolysis, and (b) a 2-AG hydrolase activity different from FAAH and down-regulated by LPS. High levels of FAAH mRNA were found in circulating macrophages but not platelets, which, however, contain a 2-AG hydrolase. Both platelets and macrophages were shown to express the mRNA for the CB1 cannabinoid receptor. A macrophage 2-AG hydrolase with apparent Km = 110 microM and Vmax = 7.9 nmol x min-1 x (mg protein)-1 was partially characterized in J774 cells and found to exhibit an optimal pH of 6-7 and little or no sensitivity to typical FAAH inhibitors. These findings demonstrate for the first time that macrophages participate in the homeostasis of the hypotensive and immunomodulatory endocannabinoid 2-AG through metabolic mechanisms that are subject to regulation.
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Affiliation(s)
- V Di Marzo
- Istituto per la Chimica di Molecole di Interesse Biologico, CNR, Napoli, Italy
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21
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Goparaju SK, Ueda N, Taniguchi K, Yamamoto S. Enzymes of porcine brain hydrolyzing 2-arachidonoylglycerol, an endogenous ligand of cannabinoid receptors. Biochem Pharmacol 1999; 57:417-23. [PMID: 9933030 DOI: 10.1016/s0006-2952(98)00314-1] [Citation(s) in RCA: 175] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Anandamide and 2-arachidonoylglycerol (2-AG) are two endogenous ligands for the cannabinoid receptors, and their cannabimimetic activities are lost when they are hydrolyzed enzymatically. Cytosol and particulate fractions of porcine brain exhibited a high 2-AG hydrolyzing activity of 100 nmol/min/mg protein. Most of the activity could be attributed to a monoacylglycerol lipase-like enzyme that did not hydrolyze anandamide. It was separated by hydroxyapatite chromatography from anandamide amidohydrolase, which is also capable of hydrolyzing 2-AG as well as anandamide. Thus, porcine brain has at least two enzymes capable of hydrolyzing 2-AG. The 2-AG hydrolase activities of both the cytosolic and particulate enzymes were irreversibly and time-dependently inhibited by methyl arachidonyl fluorophosphonate with IC50 values as low as 2-3 nM.
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Affiliation(s)
- S K Goparaju
- Department of Biochemistry, Tokushima University, School of Medicine, Japan
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22
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Goparaju SK, Ueda N, Yamaguchi H, Yamamoto S. Anandamide amidohydrolase reacting with 2-arachidonoylglycerol, another cannabinoid receptor ligand. FEBS Lett 1998; 422:69-73. [PMID: 9475172 DOI: 10.1016/s0014-5793(97)01603-7] [Citation(s) in RCA: 273] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Two endogenous ligands for cannabinoid receptors, anandamide (arachidonylethanolamide) and 2-arachidonoylglycerol, lose their biological activities by enzymatic hydrolysis. A cDNA for a rat liver enzyme hydrolyzing anandamide as well as oleamide was overexpressed in COS-7 cells. When the particulate fraction was allowed to react with 2-arachidonoylglycerol, arachidonic acid was produced. In contrast, this hydrolytic reaction did not occur with the control cells. The hydrolysis of 2-arachidonoylglycerol proceeded about 4-fold faster than the anandamide hydrolysis with a Km value as low as 6 microM and an optimal pH of 10. Phenylmethylsulfonyl fluoride and methyl arachidonyl fluorophosphonate inhibited the hydrolysis of both anandamide and 2-arachidonoylglycerol in parallel. Furthermore, the hydrolysis of [14C]2-arachidonoylglycerol was inhibited by anandamide dose-dependently. These results suggest that anandamide and 2-arachidonoylglycerol can be inactivated by the same enzyme.
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Affiliation(s)
- S K Goparaju
- Department of Biochemistry, Tokushima University, School of Medicine, Japan
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23
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Patwardhan AV, Ataai MM. Site accessibility and the pH dependence of the saturation capacity of a highly cross-linked matrix. Immobilized metal affinity chromatography of bovine serum albumin on chelating Superose. J Chromatogr A 1997; 767:11-23. [PMID: 9177004 DOI: 10.1016/s0021-9673(97)00013-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Immobilized metal ion affinity chromatography has shown promise for isolating desired proteins from a mixture based on their affinity for chelated metal ions. Using frontal analysis, the pH dependence of the saturation capacity of chelating Superose matrix for bovine serum albumin (BSA) is examined over a broad pH range. A significant increase in the capacity was observed near the elution pH of BSA (pH 4.5) from a Cu-imminodiacetic acid column. The results of several experiments indicated that this apparently abnormal variation may reflect the low degree of accessibility of a large portion of copper sites inside chelating Superose. In a broader sense, these results suggest that during frontal analysis, the assumption of column saturation based on a plateau in the exit concentration that is almost at the same level as the input concentration could be misleading for highly cross-linked matrices and relatively large sized proteins. That is, the relatively less accessible copper sites may become difficult to be reached due to high levels of protein adsorption in the more accessible regions and thus give the appearance of a plateau in the breakthrough curve prior to complete column saturation. This is likely to be the case at high pH where BSA demonstrates very high affinity for immobilized copper or at high input concentrations where the equilibrium coverage is expected to be high. The results demonstrate that the estimated saturation capacity could be significantly smaller than the actual capacity.
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Affiliation(s)
- A V Patwardhan
- Department of Chemical Engineering, University of Pittsburgh, PA 15219, USA
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