1
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Kondrat S, von Lieres E. Mechanisms and Effects of Substrate Channelling in Enzymatic Cascades. Methods Mol Biol 2022; 2487:27-50. [PMID: 35687228 DOI: 10.1007/978-1-0716-2269-8_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Substrate or metabolite channelling is a transfer of intermediates produced by one enzyme to the sequential enzyme of a reaction cascade or metabolic pathway, without releasing them entirely into bulk. Despite an enormous effort and more than three decades of research, substrate channelling remains the subject of continuing debates and active investigation. Herein, we review the benefits and mechanisms of substrate channelling in vivo and in vitro. We discuss critically the effects that substrate channelling can have on enzymatic cascades, including speeding up or slowing down reaction cascades and protecting intermediates from sequestration and enzymes' surroundings from toxic or otherwise detrimental intermediates. We also discuss how macromolecular crowding affects substrate channelling and point out the galore of open questions.
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Affiliation(s)
- Svyatoslav Kondrat
- Institute of Physical Chemistry, Polish Academy of Sciences, Warsaw, Poland.
- Max-Planck-Institut für Intelligente Systeme, Stuttgart, Germany.
- IV. Institut für Theoretische Physik, Universität Stuttgart, Stuttgart, Germany.
| | - Eric von Lieres
- Forschungszentrum Jülich, IBG-1: Biotechnology, Jülich, Germany
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2
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Pareek V, Sha Z, He J, Wingreen NS, Benkovic SJ. Metabolic channeling: predictions, deductions, and evidence. Mol Cell 2021; 81:3775-3785. [PMID: 34547238 PMCID: PMC8485759 DOI: 10.1016/j.molcel.2021.08.030] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 08/18/2021] [Accepted: 08/21/2021] [Indexed: 12/19/2022]
Abstract
With the elucidation of myriad anabolic and catabolic enzyme-catalyzed cellular pathways crisscrossing each other, an obvious question arose: how could these networks operate with maximal catalytic efficiency and minimal interference? A logical answer was the postulate of metabolic channeling, which in its simplest embodiment assumes that the product generated by one enzyme passes directly to a second without diffusion into the surrounding medium. This tight coupling of activities might increase a pathway's metabolic flux and/or serve to sequester unstable/toxic/reactive intermediates as well as prevent their access to other networks. Here, we present evidence for this concept, commencing with enzymes that feature a physical molecular tunnel, to multi-enzyme complexes that retain pathway substrates through electrostatics or enclosures, and finally to metabolons that feature collections of enzymes assembled into clusters with variable stoichiometric composition. Lastly, we discuss the advantages of reversibly assembled metabolons in the context of the purinosome, the purine biosynthesis metabolon.
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Affiliation(s)
- Vidhi Pareek
- Huck Institutes of Life Sciences, Pennsylvania State University, University Park, PA 16802, USA
| | - Zhou Sha
- Department of Chemistry, Pennsylvania State University, University Park, PA 16802, USA
| | - Jingxuan He
- Department of Chemistry, Pennsylvania State University, University Park, PA 16802, USA
| | - Ned S Wingreen
- Department of Molecular Biology and Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Stephen J Benkovic
- Department of Chemistry, Pennsylvania State University, University Park, PA 16802, USA.
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3
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Kuzmak A, Carmali S, von Lieres E, Russell AJ, Kondrat S. Can enzyme proximity accelerate cascade reactions? Sci Rep 2019; 9:455. [PMID: 30679600 PMCID: PMC6345930 DOI: 10.1038/s41598-018-37034-3] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Accepted: 11/26/2018] [Indexed: 01/23/2023] Open
Abstract
The last decade has seen an exponential expansion of interest in conjugating multiple enzymes of cascades in close proximity to each other, with the overarching goal being to accelerate the overall reaction rate. However, some evidence has emerged that there is no effect of proximity channeling on the reaction velocity of the popular GOx-HRP cascade, particularly in the presence of a competing enzyme (catalase). Herein, we rationalize these experimental results quantitatively. We show that, in general, proximity channeling can enhance reaction velocity in the presence of competing enzymes, but in steady state a significant enhancement can only be achieved for diffusion-limited reactions or at high concentrations of competing enzymes. We provide simple equations to estimate the effect of channeling quantitatively and demonstrate that proximity can have a more pronounced effect under crowding conditions in vivo, particularly that crowding can enhance the overall rates of channeled cascade reactions.
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Affiliation(s)
- Andrij Kuzmak
- Department for Theoretical Physics, I. Franko National University of Lviv, Lviv, Ukraine
| | - Sheiliza Carmali
- Department of Chemistry, Aarhus University, 8000, Aarhus C, Denmark.,Center for Polymer-Based Protein Engineering, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA, 15213, USA
| | - Eric von Lieres
- Forschungszentrum Jülich, IBG-1: Biotechnology, 52425, Jülich, Germany
| | - Alan J Russell
- Center for Polymer-Based Protein Engineering, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA, 15213, USA.,Department of Chemical Engineering, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA, 15213, USA
| | - Svyatoslav Kondrat
- Forschungszentrum Jülich, IBG-1: Biotechnology, 52425, Jülich, Germany. .,Department of Complex Systems, Institute of Physical Chemistry, Warsaw, Poland.
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4
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Reinhold D, Pielke-Lombardo H, Jacobson S, Ghosh D, Kechris K. Pre-analytic Considerations for Mass Spectrometry-Based Untargeted Metabolomics Data. Methods Mol Biol 2019; 1978:323-340. [PMID: 31119672 PMCID: PMC7346099 DOI: 10.1007/978-1-4939-9236-2_20] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Metabolomics is the science of characterizing and quantifying small molecule metabolites in biological systems. These metabolites give organisms their biochemical characteristics, providing a link between genotype, environment, and phenotype. With these opportunities also come data challenges, such as compound annotation, missing values, and batch effects. We present the steps of a general pipeline to process untargeted mass spectrometry data to alleviate the latter two challenges. We assume to have a matrix with metabolite abundances, with metabolites in rows and samples in columns. The steps in the pipeline include summarizing technical replicates (if available), filtering, imputing, transforming, and normalizing the data. In each of these steps, a method and parameters should be chosen based on assumptions one is willing to make, the question of interest, and diagnostic tools. Besides giving a general pipeline that can be adapted by the reader, our goal is to review diagnostic tools and criteria that are helpful when making decisions in each step of the pipeline and assessing the effectiveness of normalization and batch correction. We conclude by giving a list of useful packages and discuss some alternative approaches that might be more appropriate for the reader's data.
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Affiliation(s)
| | - Harrison Pielke-Lombardo
- Computational Bioscience Program, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Sean Jacobson
- Center for Genes, Environment, and Health, National Jewish Health, Denver, CO, USA
| | - Debashis Ghosh
- Department of Biostatistics and Informatics, Colorado School of Public Health, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Katerina Kechris
- Department of Biostatistics and Informatics, Colorado School of Public Health, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.
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5
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Han J, Qin WX, Li ZL, Xu AJ, Xing H, Wu H, Zhang H, Wang MD, Li C, Liang L, Quan B, Yan WT, Shen F, Wu MC, Yang T. Tissue and serum metabolite profiling reveals potential biomarkers of human hepatocellular carcinoma. Clin Chim Acta 2018; 488:68-75. [PMID: 30389456 DOI: 10.1016/j.cca.2018.10.039] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2018] [Revised: 10/10/2018] [Accepted: 10/29/2018] [Indexed: 12/22/2022]
Abstract
BACKGROUND AND AIMS Metabolomics serves as an important tool in distinguishing changes in metabolic pathways and the diagnosis of human disease. Hepatocellular carcinoma (HCC) is a malignance present of heterogeneous metabolic disorder and lack of effective biomarker for surveillance and diagnosis. In this study, we searched for potential metabolite biomarkers of HCC using tissue and serum metabolomics approach. METHODS A total of 30 pairs of matched liver tissue samples from HCC patients and 90 serum samples (30 HCC patients, 30 liver cirrhosis patients, and 30 healthy individuals) were assessed. Metabolomics was performed through ultra performance liquid chromatography-mass spectrometry in conjunction with multivariate and univariate statistical analyses. RESULTS A total of six differential metabolites including chenodeoxycholic acid (CDCA), glycocholic acid (GCA), LPC20:5, LPE18:0, succinyladenosine and uridine were present in HCC tissue and serum samples. CDCA, LPC20:5, succinyladenosine and uridine were used to construct a diagnostic model based on logistic regression. The four-metabolite panel discriminated HCC from liver cirrhosis with an AUC score of 0.938, sensitivity of 93.3% and specificity of 86.7%. For all HCC and cirrhosis patients, the diagnostic accuracy increased to 96.7% and 90.0%, respectively. CONCLUSION The combination of CDCA, LPC20:5, succinyladenosine and uridine can be used as a biomarker panel to improve HCC sensitivity and specificity. This panel significantly benefits HCC diagnostics and reveals new insight into HCC pathogenesis.
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Affiliation(s)
- Jun Han
- Department of Hepatobiliary Surgery, Eastern Hepatobiliary Surgery Hospital, Second Military Medical University, Shanghai 200438, China
| | - Wen-Xing Qin
- Department of Clinical Oncology, Changzheng Hospital, Second Military Medical University, Shanghai 200003, China; State Key Laboratory of New Drug & Pharmaceutial Process, Shanghai Institute of Pharmaceutial Industry, Shanghai 200437, China
| | - Zhen-Li Li
- Department of Hepatobiliary Surgery, Eastern Hepatobiliary Surgery Hospital, Second Military Medical University, Shanghai 200438, China
| | - Ai-Jing Xu
- Department of Infectious Disease, Changhai Hospital, Second Military Medical University, Shanghai 200433, China
| | - Hao Xing
- Department of Hepatobiliary Surgery, Eastern Hepatobiliary Surgery Hospital, Second Military Medical University, Shanghai 200438, China
| | - Han Wu
- Department of Hepatobiliary Surgery, Eastern Hepatobiliary Surgery Hospital, Second Military Medical University, Shanghai 200438, China
| | - Han Zhang
- Department of Hepatobiliary Surgery, Eastern Hepatobiliary Surgery Hospital, Second Military Medical University, Shanghai 200438, China
| | - Ming-da Wang
- Department of Hepatobiliary Surgery, Eastern Hepatobiliary Surgery Hospital, Second Military Medical University, Shanghai 200438, China
| | - Chao Li
- Department of Hepatobiliary Surgery, Eastern Hepatobiliary Surgery Hospital, Second Military Medical University, Shanghai 200438, China
| | - Lei Liang
- Department of Hepatobiliary Surgery, Eastern Hepatobiliary Surgery Hospital, Second Military Medical University, Shanghai 200438, China
| | - Bing Quan
- Department of Clinical Medicine, Second Military Medical University, Shanghai 200433, China
| | - Wen-Tao Yan
- Department of Clinical Medicine, Second Military Medical University, Shanghai 200433, China
| | - Feng Shen
- Department of Hepatobiliary Surgery, Eastern Hepatobiliary Surgery Hospital, Second Military Medical University, Shanghai 200438, China
| | - Meng-Chao Wu
- Department of Hepatobiliary Surgery, Eastern Hepatobiliary Surgery Hospital, Second Military Medical University, Shanghai 200438, China.
| | - Tian Yang
- Department of Hepatobiliary Surgery, Eastern Hepatobiliary Surgery Hospital, Second Military Medical University, Shanghai 200438, China.
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Poshyvailo L, von Lieres E, Kondrat S. Does metabolite channeling accelerate enzyme-catalyzed cascade reactions? PLoS One 2017; 12:e0172673. [PMID: 28234973 PMCID: PMC5325314 DOI: 10.1371/journal.pone.0172673] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Accepted: 02/08/2017] [Indexed: 12/30/2022] Open
Abstract
Metabolite or substrate channeling is a direct transfer of metabolites from one enzyme to the next enzyme in a cascade. Among many potential advantages of substrate channeling, acceleration of the total reaction rate is considered as one of the most important and self-evident. However, using a simple model, supported by stochastic simulations, we show that it is not always the case; particularly at long times (i.e. in steady state) and high substrate concentrations, a channeled reaction cannot be faster, and can even be slower, than the original non-channeled cascade reaction. In addition we show that increasing the degree of channeling may lead to an increase of the metabolite pool size. We substantiate that the main advantage of channeling likely lies in protecting metabolites from degradation or competing side reactions.
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Affiliation(s)
- Liubov Poshyvailo
- Forschungszentrum Jülich, IBG-1: Biotechnology, Jülich, Germany
- Forschungszentrum Jülich, IEK-7: Institute of Energy and Climate Research, Jülich, Germany
| | - Eric von Lieres
- Forschungszentrum Jülich, IBG-1: Biotechnology, Jülich, Germany
| | - Svyatoslav Kondrat
- Forschungszentrum Jülich, IBG-1: Biotechnology, Jülich, Germany
- * E-mail: ,
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7
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He F, Murabito E, Westerhoff HV. Synthetic biology and regulatory networks: where metabolic systems biology meets control engineering. J R Soc Interface 2016; 13:rsif.2015.1046. [PMID: 27075000 DOI: 10.1098/rsif.2015.1046] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2015] [Accepted: 03/21/2016] [Indexed: 12/25/2022] Open
Abstract
Metabolic pathways can be engineered to maximize the synthesis of various products of interest. With the advent of computational systems biology, this endeavour is usually carried out through in silico theoretical studies with the aim to guide and complement further in vitro and in vivo experimental efforts. Clearly, what counts is the result in vivo, not only in terms of maximal productivity but also robustness against environmental perturbations. Engineering an organism towards an increased production flux, however, often compromises that robustness. In this contribution, we review and investigate how various analytical approaches used in metabolic engineering and synthetic biology are related to concepts developed by systems and control engineering. While trade-offs between production optimality and cellular robustness have already been studied diagnostically and statically, the dynamics also matter. Integration of the dynamic design aspects of control engineering with the more diagnostic aspects of metabolic, hierarchical control and regulation analysis is leading to the new, conceptual and operational framework required for the design of robust and productive dynamic pathways.
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Affiliation(s)
- Fei He
- Department of Automatic Control and Systems Engineering, University of Sheffield, Sheffield S1 3JD, UK
| | - Ettore Murabito
- The Manchester Centre for Integrative Systems Biology, Manchester Institute for Biotechnology, School for Chemical Engineering and Analytical Science, University of Manchester, Manchester M1 7DN, UK
| | - Hans V Westerhoff
- The Manchester Centre for Integrative Systems Biology, Manchester Institute for Biotechnology, School for Chemical Engineering and Analytical Science, University of Manchester, Manchester M1 7DN, UK Department of Synthetic Systems Biology, Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands Department of Molecular Cell Physiology, VU University Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands
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8
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Gralka E, Luchinat C, Tenori L, Ernst B, Thurnheer M, Schultes B. Metabolomic fingerprint of severe obesity is dynamically affected by bariatric surgery in a procedure-dependent manner. Am J Clin Nutr 2015; 102:1313-22. [PMID: 26581381 DOI: 10.3945/ajcn.115.110536] [Citation(s) in RCA: 86] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Accepted: 09/16/2015] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Obesity is associated with multiple diseases. Bariatric surgery is the most effective therapy for severe obesity that can reduce body weight and obesity-associated morbidity. The metabolic alterations associated with obesity and respective changes after bariatric surgery are incompletely understood. OBJECTIVE We comprehensively assessed metabolic alterations associated with severe obesity and distinct bariatric procedures. DESIGN In our longitudinal observational study, we applied a (1)H-nuclear magnetic resonance-based global, untargeted metabolomics strategy on human serum samples that were collected before and repeatedly ≤1 y after distinct bariatric procedures [i.e., a sleeve gastrectomy, proximal Roux-en Y gastric bypass (RYGB), and distal RYGB]. For comparison, we also analyzed serum samples from normal-weight and less-obese subjects who were matched for 1-y postoperative body mass index (BMI) values of the surgical groups. RESULTS We identified a metabolomic fingerprint in obese subjects that was clearly discriminated from that of normal-weight subjects. Furthermore, we showed that bariatric surgery (sleeve gastrectomy and proximal and distal RYGB) dynamically affected this fingerprint in a procedure-dependent manner, thereby establishing new fingerprints that could be discriminated from those of BMI-matched and normal-weight control subjects. Metabolites that largely contributed to the metabolomic fingerprints of severe obesity were aromatic and branched-chain amino acids (elevated), metabolites related to energy metabolism (pyruvate and citrate; elevated), and metabolites suggested to be derived from gut microbiota (formate, methanol, and isopropanol; all elevated). CONCLUSION Our data indicate that bariatric surgery, irrespective of the specific kind of procedure used, reverses most of the metabolic alterations associated with obesity and suggest profound changes in gut microbiome-host interactions after the surgery. This trial was registered at clinicaltrials.gov as NCT02480322.
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Affiliation(s)
- Ewa Gralka
- FiorGen Foundation, Sesto Fiorentino, Italy; Magnetic Resonance Center and
| | - Claudio Luchinat
- Magnetic Resonance Center and Chemistry Department, University of Florence, Sesto Fiorentino, Italy; and
| | | | - Barbara Ernst
- eSwiss Medical & Surgical Center, Interdisciplinary Obesity Center, St. Gallen, Switzerland
| | - Martin Thurnheer
- eSwiss Medical & Surgical Center, Interdisciplinary Obesity Center, St. Gallen, Switzerland
| | - Bernd Schultes
- eSwiss Medical & Surgical Center, Interdisciplinary Obesity Center, St. Gallen, Switzerland
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9
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Haanstra JR, Bakker BM, Michels PA. In or out? On the tightness of glycosomal compartmentalization of metabolites and enzymes in Trypanosoma brucei. Mol Biochem Parasitol 2014; 198:18-28. [DOI: 10.1016/j.molbiopara.2014.11.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Revised: 11/10/2014] [Accepted: 11/20/2014] [Indexed: 11/16/2022]
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10
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Metabolomics of Human Brain Aging and Age-Related Neurodegenerative Diseases. J Neuropathol Exp Neurol 2014; 73:640-57. [DOI: 10.1097/nen.0000000000000091] [Citation(s) in RCA: 138] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
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11
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Szwergold BS. Maillard reactions in hyperthermophilic archaea: implications for better understanding of non-enzymatic glycation in biology. Rejuvenation Res 2014; 16:259-72. [PMID: 23634960 DOI: 10.1089/rej.2012.1401] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Maillard reactions are an unavoidable feature of life that appear to be damaging to cell and organisms. Consequently, all living systems must have ways to protect themselves against this process. As of 2012, several such defense mechanisms have been identified. They are all enzymatic and were found in mesophilic organisms. To date, no systematic study of Maillard reactions and the relevant defense mechanisms has been conducted in thermophiles (50°C-80°C) or hyperthermophiles (80°C-120°C). This is surprisingly because Maillard reactions become significantly faster and potent with increasing temperatures. This review examines this neglected issue in two well-defined sets of hyperthermophiles. My analysis suggests that hyperthermophiles cope with glycation stress by several mechanisms: • Absence of glycation-prone head groups (such as ethanoalamine) from hyperthermophilic phospholipids • Protection of reactive carbohydrates and labile metabolic intermediates by substrate channeling. • Conversion of excess reactive sugars such as glucose to non-reactive compounds including trehalose, di-myo-inositol-phosphate and mannosylglycerate. • Detoxification of methylglyoxal and other ketoaldehydes by conversion to inert products through a variety of reductases and dehydrogenases. • Scavenging of the remaining carbonyls by nucleophilic amines, including a variety of novel polyamines. Disruption of the Maillard process at its early stages, rather than repair of damage caused by it at later stages, appears to be the preferred strategy in the organisms examined. The most unique among these mechanisms appears to be a polyamine-based scavenging system. Undertaking research of the Maillard process in hyperthermophiles is important in its own right and is also likely to provide new insights for the control of these reactions in humans, especially in diseases such as diabetes mellitus.
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Gahlaut A, Vikas, Dahiya M, Gothwal A, Kulharia M, Chhillar AK, Hooda V, Dabur R. Proteomics & metabolomics: Mapping biochemical regulations. ACTA ACUST UNITED AC 2013. [DOI: 10.1016/j.dit.2013.08.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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13
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Buchner A, Tostevin F, Hinzpeter F, Gerland U. Optimization of collective enzyme activity via spatial localization. J Chem Phys 2013; 139:135101. [DOI: 10.1063/1.4823504] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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14
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Metabolomics in plants and humans: applications in the prevention and diagnosis of diseases. BIOMED RESEARCH INTERNATIONAL 2013; 2013:792527. [PMID: 23986911 PMCID: PMC3748395 DOI: 10.1155/2013/792527] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Accepted: 07/07/2013] [Indexed: 11/23/2022]
Abstract
In the recent years, there has been an increase in the number of metabolomic approaches used, in parallel with proteomic and functional genomic studies. The wide variety of chemical types of metabolites available has also accelerated the use of different techniques in the investigation of the metabolome. At present, metabolomics is applied to investigate several human diseases, to improve their diagnosis and prevention, and to design better therapeutic strategies. In addition, metabolomic studies are also being carried out in areas such as toxicology and pharmacology, crop breeding, and plant biotechnology. In this review, we emphasize the use and application of metabolomics in human diseases and plant research to improve human health.
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15
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Buchner A, Tostevin F, Gerland U. Clustering and optimal arrangement of enzymes in reaction-diffusion systems. PHYSICAL REVIEW LETTERS 2013; 110:208104. [PMID: 25167456 DOI: 10.1103/physrevlett.110.208104] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Indexed: 06/03/2023]
Abstract
Enzymes within biochemical pathways are often colocalized, yet the consequences of specific spatial enzyme arrangements remain poorly understood. We study the impact of enzyme arrangement on reaction efficiency within a reaction-diffusion model. The optimal arrangement transitions from a cluster to a distributed profile as a single parameter, which controls the probability of reaction versus diffusive loss of pathway intermediates, is varied. We introduce the concept of enzyme exposure to explain how this transition arises from the stochastic nature of molecular reactions and diffusion.
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Affiliation(s)
- Alexander Buchner
- Arnold Sommerfeld Center for Theoretical Physics and Center for Nanoscience, Ludwig-Maximilians-Universität München, Theresienstraße 37, D-80333 München, Germany
| | - Filipe Tostevin
- Arnold Sommerfeld Center for Theoretical Physics and Center for Nanoscience, Ludwig-Maximilians-Universität München, Theresienstraße 37, D-80333 München, Germany
| | - Ulrich Gerland
- Arnold Sommerfeld Center for Theoretical Physics and Center for Nanoscience, Ludwig-Maximilians-Universität München, Theresienstraße 37, D-80333 München, Germany
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16
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Li J, Huang C, Zheng D, Wang Y, Yuan Z. CcpA-Mediated Enhancement of Sugar and Amino Acid Metabolism in Lysinibacillus sphaericus by NMR-Based Metabolomics. J Proteome Res 2012; 11:4654-61. [DOI: 10.1021/pr300469v] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Jing Li
- Center for Applied and Environmental
Microbiology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, People’s Republic
of China
- Graduate School of the Chinese Academy of Sciences, Beijing 100039,
People’s Republic of China
| | - Chongyang Huang
- Wuhan Center of
Magnetic Resonance,
State Key Laboratory of Magnetic Resonance and Atomic and Molecular
Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, People’s
Republic of China
- Graduate School of the Chinese Academy of Sciences, Beijing 100039,
People’s Republic of China
| | - Dasheng Zheng
- Center for Applied and Environmental
Microbiology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, People’s Republic
of China
| | - Yulan Wang
- Wuhan Center of
Magnetic Resonance,
State Key Laboratory of Magnetic Resonance and Atomic and Molecular
Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, People’s
Republic of China
| | - Zhiming Yuan
- Center for Applied and Environmental
Microbiology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, People’s Republic
of China
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17
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D’Alessandro A, Zolla L. Metabolomics and cancer drug discovery: let the cells do the talking. Drug Discov Today 2012; 17:3-9. [DOI: 10.1016/j.drudis.2011.09.017] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2011] [Revised: 09/15/2011] [Accepted: 09/28/2011] [Indexed: 01/08/2023]
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18
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Bernini P, Bertini I, Luchinat C, Tenori L, Tognaccini A. The cardiovascular risk of healthy individuals studied by NMR metabonomics of plasma samples. J Proteome Res 2011; 10:4983-92. [PMID: 21902250 DOI: 10.1021/pr200452j] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The identification and the present wide acceptance of cardiovascular risk factors such as age, sex, hypertension, hyperlipidemia, smoking, obesity, diabetes, and physical inactivity have led to dramatic reductions in cardiovascular morbidity and mortality. However, novel risk predictors present opportunities to identify more patients at risk and to more accurately define the biochemical signature of that risk. In this paper, we present a comprehensive metabonomic analysis of 864 plasma samples from healthy volunteers, through Nuclear Magnetic Resonance (NMR) and multivariate statistical analysis (regression and classification). We have found that subjects that are classified as at high or at low risk using the common clinical markers can also be discriminated using NMR metabonomics. This discrimination is not only due to common markers (such as total cholesterol, triglycerides, LDL, HDL), but also to (p < 0.05 after Bonferroni correction) other metabolites (e.g., 3-hydroxybutyrate, α-ketoglutarate, threonine, dimethylglycine) previously not associated with cardiovascular diseases.
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Affiliation(s)
- Patrizia Bernini
- Magnetic Resonance Center, University of Florence, Sesto Fiorentino, Italy
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19
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Cao DL, Ye DW, Zhu Y, Zhang HL, Wang YX, Yao XD. Efforts to resolve the contradictions in early diagnosis of prostate cancer: a comparison of different algorithms of sarcosine in urine. Prostate Cancer Prostatic Dis 2011; 14:166-72. [DOI: 10.1038/pcan.2011.2] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Biochemical disorders induced by cytotoxic marine natural products in breast cancer cells as revealed by proton NMR spectroscopy-based metabolomics. Biochem Pharmacol 2010; 80:1170-9. [PMID: 20637732 DOI: 10.1016/j.bcp.2010.07.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2010] [Revised: 07/05/2010] [Accepted: 07/07/2010] [Indexed: 12/16/2022]
Abstract
Marine plants and animals are sources of a huge number of pharmacologically active compounds, some of which exhibit antineoplastic activity of clinical relevance. However the mechanism of action of marine natural products (MNPs) is poorly understood. In this study, proton NMR spectroscopy-based metabolomics was applied to unravel biochemical disorders induced in human MCF7 breast cancer cells by 3 lead candidate anticancer MNPs: ascididemin (Asc), lamellarin-D (Lam-D), and kahalalide F (KF). Asc, Lam-D, and KF provoked a severe decrease in DNA content in MCF7 cells after 24-h treatment. Asc and Lam-D provoked apoptosis, whereas KF induced non-apoptotic cell death. Metabolite profiling revealed major biochemical disorders following treatment. The response of MCF7 tumor cells to Asc involved the accumulation of citrate (x17 the control level, P<0.001), testifying enzyme blockade in citrate metabolism, and the accumulation of gluconate (x9.8, P<0.005), a metabolite never reported at such concentration in tumor cells, probably testifying glycolysis shutdown. The response to Lam-D involved the accumulation of aspartate (x7.2, P<0.05), glutamate (x14.7, P<0.05), and lactate (x2.3, P<0.05), probably in relation with the targeting of the malate-aspartate shuttle, as discussed. The response to KF involved increased lipid accumulation (polyunsaturated fatty acids x9.8, P<0.05), and phospholipid and acetate derivative alterations. Altogether, this study demonstrates the potential of proton NMR spectroscopy-based metabolomics to help uncover metabolic targets and elucidate the mechanism of cytotoxicity of candidate antineoplastic MNPs.
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Spratlin JL, Serkova NJ, Eckhardt SG. Clinical applications of metabolomics in oncology: a review. Clin Cancer Res 2009; 15:431-40. [PMID: 19147747 DOI: 10.1158/1078-0432.ccr-08-1059] [Citation(s) in RCA: 518] [Impact Index Per Article: 34.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Metabolomics, an omic science in systems biology, is the global quantitative assessment of endogenous metabolites within a biological system. Either individually or grouped as a metabolomic profile, detection of metabolites is carried out in cells, tissues, or biofluids by either nuclear magnetic resonance spectroscopy or mass spectrometry. There is potential for the metabolome to have a multitude of uses in oncology, including the early detection and diagnosis of cancer and as both a predictive and pharmacodynamic marker of drug effect. Despite this, there is lack of knowledge in the oncology community regarding metabolomics and confusion about its methodologic processes, technical challenges, and clinical applications. Metabolomics, when used as a translational research tool, can provide a link between the laboratory and clinic, particularly because metabolic and molecular imaging technologies, such as positron emission tomography and magnetic resonance spectroscopic imaging, enable the discrimination of metabolic markers noninvasively in vivo. Here, we review the current and potential applications of metabolomics, focusing on its use as a biomarker for cancer diagnosis, prognosis, and therapeutic evaluation.
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Affiliation(s)
- Jennifer L Spratlin
- Department of Medical Oncology, University of Colorado Health Sciences Center, Denver, Colorado, USA.
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Bertini I, Calabrò A, De Carli V, Luchinat C, Nepi S, Porfirio B, Renzi D, Saccenti E, Tenori L. The metabonomic signature of celiac disease. J Proteome Res 2009; 8:170-7. [PMID: 19072164 DOI: 10.1021/pr800548z] [Citation(s) in RCA: 119] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Celiac disease (CD) is a multifactorial disorder involving genetic and environmental factors, thus, having great potential impact on metabolism. This study aims at defining the metabolic signature of CD through Nuclear Magnetic Resonance (NMR) of urine and serum samples of CD patients. Thirty-four CD patients at diagnosis and 34 healthy controls were examined by (1)H NMR of their serum and urine. A CD patients' subgroup was also examined after a gluten-free diet (GFD). Projection to Latent Structures provided data reduction and clustering, and Support Vector Machines provided pattern recognition and classification. The classification accuracy of CD and healthy control groups was 79.7-83.4% for serum and 69.3% for urine. Sera of CD patients were characterized by lower levels (P < 0.01) of several metabolites such as amino acids, lipids, pyruvate and choline, and by higher levels of glucose and 3-hydroxybutyric acid, while urines showed altered levels (P < 0.05) of, among others, indoxyl sulfate, meta-[hydroxyphenyl]propionic acid and phenylacetylglycine. After 12 months of GFD, all but one of the patients were classified as healthy by the same statistical analysis. NMR thus reveals a characteristic metabolic signature of celiac disease. Altered serum levels of glucose and ketonic bodies suggest alterations of energy metabolism, while the urine data point to alterations of gut microbiota. Metabolomics may thus provide further hints on the biochemistry of the disease.
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Affiliation(s)
- Ivano Bertini
- Magnetic Resonance Center (CERM), University of Florence, Via L.Sacconi 6, 50019 Sesto Fiorentino, Italy.
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Barba I, Fernandez-Montesinos R, Garcia-Dorado D, Pozo D. Alzheimer's disease beyond the genomic era: nuclear magnetic resonance (NMR) spectroscopy-based metabolomics. J Cell Mol Med 2008; 12:1477-85. [PMID: 18554316 PMCID: PMC3918063 DOI: 10.1111/j.1582-4934.2008.00385.x] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Alzheimer's disease (AD) is a complex disease, with no definitive biomarkers available that allow clinical diagnosis; this represents a major problem for the advance of efficient drug discovery programs. A successful approach towards the understanding and treatment of AD should take into consideration this complex nature. In this sense, metabolic networks are subject to severe stoichiometric restrictions. Metabolomics amplifies changes both in the proteome and the genome, and represents a more accurate approximation to the phenotype of an organism in health and disease. In this article, we will examine the current rationale for metabolomics in AD, its basic methodology and the available data in animal models and human studies. The discussed topics will highlight the importance of being able to use the metabolomic information in order to understand disease mechanisms from a systems biology perspective as a non-invasive approach to diagnose and grade AD. This could allow the assessment of new therapies during clinical trials, the identification of patients at risk to develop adverse effects during treatment and the final implementation of new tools towards a more personalized medicine.
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Affiliation(s)
- Ignasi Barba
- Laboratory of Experimental Cardiology, Cardiology Service, Institut de Recerca Hospital Vall d'Hebron, Barcelona, Spain
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Kell DB. Systems biology, metabolic modelling and metabolomics in drug discovery and development. Drug Discov Today 2006; 11:1085-92. [PMID: 17129827 DOI: 10.1016/j.drudis.2006.10.004] [Citation(s) in RCA: 219] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2006] [Revised: 09/25/2006] [Accepted: 10/09/2006] [Indexed: 01/03/2023]
Abstract
Unlike signalling pathways, metabolic networks are subject to strict stoichiometric constraints. Metabolomics amplifies changes in the proteome, and represents more closely the phenotype of an organism. Recent advances enable the production (and computer-readable encoding as SBML) of metabolic network models reconstructed from genome sequences, as well as experimental measurements of much of the metabolome. There is increasing convergence between the number of human metabolites estimated via genomics ( approximately 3000) and the number measured experimentally. It is thus both timely, and now possible, to bring these two approaches together as an integrated (if distributed) whole to help understand the genesis of metabolic biomarkers, the progress of disease, and the modes of action, efficacy, off-target effects and toxicity of pharmaceutical drugs.
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Affiliation(s)
- Douglas B Kell
- School of Chemistry, Faraday Building, The University of Manchester. PO Box 88, Manchester, M60 1QD, UK.
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Abstract
Neuroendocrine (NE) cancers occur in multiple anatomic locations and range in prognosis from indolent to aggressive. In addition, adenocarcinomas can express gene products associated with NE cells, referred to as NE differentiation (NED), which correlates with poor prognosis and aggressive disease. Several metabolites and peptides produced by NE cells have been discovered that engage in cellular signaling and have autocrine and paracrine effects on cancer cell proliferation. This review focuses on the current knowledge of small molecule metabolism in NE cancers involving the synthesis of biogenic amine, polyamine, and amino acid neurotransmitters. Systems biology-directed approaches to NE cancer metabolism using gene expression profiling, liquid chromatography/mass spectrometry (LC/MS) and nuclear magnetic resonance (NMR) are also discussed. Furthermore, knowledge of metabolic and signaling pathways in NE cancers has led to the successful implementation of therapeutic regimens in cell culture and animal models of NE carcinogenesis.
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Affiliation(s)
- Joseph E Ippolito
- Center for Genome Sciences, Washington University School of Medicine, St. Louis, MO 63108, USA.
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Kell DB, Brown M, Davey HM, Dunn WB, Spasic I, Oliver SG. Metabolic footprinting and systems biology: the medium is the message. Nat Rev Microbiol 2005; 3:557-65. [PMID: 15953932 DOI: 10.1038/nrmicro1177] [Citation(s) in RCA: 261] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
One element of classical systems analysis treats a system as a black or grey box, the inner structure and behaviour of which can be analysed and modelled by varying an internal or external condition, probing it from outside and studying the effect of the variation on the external observables. The result is an understanding of the inner make-up and workings of the system. The equivalent of this in biology is to observe what a cell or system excretes under controlled conditions - the 'metabolic footprint' or exometabolome - as this is readily and accurately measurable. Here, we review the principles, experimental approaches and scientific outcomes that have been obtained with this useful and convenient strategy.
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Affiliation(s)
- Douglas B Kell
- School of Chemistry, University of Manchester, Faraday Building, PO Box 88, Sackville Street, Manchester M60 1QD, UK.
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Flores S, de Anda-Herrera R, Gosset G, Bolívar FG. Growth-rate recovery of Escherichia coli cultures carrying a multicopy plasmid, by engineering of the pentose-phosphate pathway. Biotechnol Bioeng 2005; 87:485-94. [PMID: 15286986 DOI: 10.1002/bit.20137] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Expression of plasmid-encoded genes in bacteria is the most common strategy for the production of specific proteins in biotechnological processes. However, the synthesis of plasmid-encoded proteins and plasmid-DNA replication often places a metabolic load (metabolic burden) into the cell's biochemical capacities that usually reduces the growth rate of the producing culture (Glick BR. Biotechnol Adv 1995;13:247-261). This metabolic burden may be related to a limited capacity of the cell to supply the extra demand of building blocks and energy required to replicate plasmid DNA and express foreign multicopy genes. Some of these required blocks are intermediaries of the pentose phosphate (PP) pathway, e.g., ribose-5-phosphate, erythrose-4-phosphate. Due to the important impact of metabolic burden on biotechnological processes, several groups have worked on developing strategies to overcome this problem, like reduction of plasmid copy number (Seo JH, Bailey JE. Biotechnol Bioeng 1985;27:1668-1674; Jones KL, Kim S, Keasling JD. Metab Eng 2000;3:328-338), chromosomal insertion of the gene which product is desired, or changing the plasmid-coded antibiotic resistance gene (Hong Y, Pasternak JJ, Glick BR. Can J Microbiol 1995;41:624-628). However, few efforts have been attempted to overcome the reduction of growth rate due to protein over-expression, by modifying central metabolic pathways (Chou C-H, Bennett GN, San KY. Biotechnol Bioeng 1994;44:952-960). We constructed a high-copy number plasmid carrying the gene for glucose-6-phosphate dehydrogenase, zwf, under the control of an inducible trc promoter (pTRzwf04 plasmid). By transforming a wild-type strain and inducing with IPTG, it was possible to recover growth-rate from 0.46 h(-1) (uninduced) to 0.64 h(-1) (induced). The same transformation in an Escherichia coli zwf(-), allows a growth-rate recovery from 0.43 h(-1) (uninduced) to 0.62 h(-1) (induced). We also studied this effect as part of a laboratory-scale biotechnology process: production of a recombinant insulin peptide by co-transforming E. coli JM101 strain with pTRzwf07, a low-copy-number plasmid that carries the same inducible construction as pTRzwf04, and with the pTEXP-MMRPI vector that carries a TrpLE-proinsulin hybrid gene. In this system, production of TrpLE-proinsulin strongly reduces growth rate; however, overexpression of zwf gene recovers with a growth rate from 0.1 h(-1) in the TrpLE-proinsulin induced strain, to 0.37 h(-1) when both zwf and TrpLE-proinsulin genes were induced. In this paper, we show that the engineering of the pentose phosphate pathway by modulation of the zwf gene expression level partially overcomes the possible bottleneck for the supply of building blocks and reducing power synthesized through the PP pathway, that are required for plasmid replication and plasmid-encoded protein expression.
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Affiliation(s)
- Salvador Flores
- Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad 2001, Col. Chamilpa, C.P. 62250, Cuernavaca, Mexico
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Anderson LE, Gatla N, Carol AA. Enzyme co-localization in pea leaf chloroplasts: glyceraldehyde-3-P dehydrogenase, triose-P isomerase, aldolase and sedoheptulose bisphosphatase. PHOTOSYNTHESIS RESEARCH 2005; 83:317-28. [PMID: 16143921 DOI: 10.1007/s11120-005-0790-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2004] [Accepted: 01/18/2005] [Indexed: 05/04/2023]
Abstract
Nearest neighbor analysis of immunocytolocalization experiments indicates that the enzymes glyceraldehyde-3-P dehydrogenase, triose-P isomerase and aldolase are located close to one another in the pea leaf chloroplast stroma, and that aldolase is located close to sedoheptulose bisphosphatase. Direct transfer of the triose phosphates between glyceraldehyde-3-P dehydrogenase and triose-P isomerase, and from glyceraldehyde-3-P dehydrogenase and triose-P isomerase to aldolase, is then a possibility, as is direct transfer of sedoheptulose bisphosphate from aldolase to sedoheptulose bisphosphatase. Spatial organization of these enzymes may be important for efficient CO(2) fixation in photosynthetic organisms. In contrast, there is no indication that fructose bisphosphatase is co-localized with aldolase, and direct transfer of fructose bisphosphate from aldolase to fructose bisphosphatase seems unlikely.
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Affiliation(s)
- Louise E Anderson
- Department of Biological Sciences, University of Illinois-Chicago, 60607, USA.
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Affiliation(s)
- Julian L Griffin
- Department of Biochemistry, University of Cambridge, Tennis Court Road, CB2 1GA, UK
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Daniel RM, van Eckert R, Holden JF, Truter J, Crowan DA. The stability of biomolecules and the implications for life at high temperatures. THE SUBSEAFLOOR BIOSPHERE AT MID-OCEAN RIDGES 2004. [DOI: 10.1029/144gm03] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
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Flores S, Gosset G, Flores N, de Graaf AA, Bolívar F. Analysis of carbon metabolism in Escherichia coli strains with an inactive phosphotransferase system by (13)C labeling and NMR spectroscopy. Metab Eng 2002; 4:124-37. [PMID: 12009792 DOI: 10.1006/mben.2001.0209] [Citation(s) in RCA: 121] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
We have developed Escherichia coli strains that internalize glucose utilizing the GalP permease instead of the phosphoenolpyruvate:carbohydrate phosphotransferase system. It has been demonstrated that a strain with these modifications (PTS(-)Glc(+)) can direct more carbon flux into the aromatic pathway than the wild-type parental strain (N. Flores et al., 1996, Nat. Biotechnol. 14, 620-623; G. Gosset et al., 1996, J. Ind. Microbiol. 17, 47-52; J. L. Baéz et al., 2001, Biotechnol. Bioeng. 73, 530-535). In this study, we have determined and compared the carbon fluxes of a wild-type strain (JM101), a PTS(-)Glc(-) strain, and two isogenic PTS(-)Glc(+) derivatives named PB12 and PB13 by combining genetic, biochemical, and NMR approaches. It was determined that in these strains a functional glk gene in the chromosome is required for rapid glucose consumption; furthermore, glucokinase-specific activities were higher than in the wild-type strain. (13)C labeling and NMR analysis allowed the determination of differences in vivo which include higher glycolytic fluxes of 93.1 and 89.2% compared with the 76.6% obtained for the wild-type E. coli. In PB12 and PB13 we found a flux through the malic enzymes of 4 and 10%, respectively, compared to zero in the wild-type strain. While flux through the Pck enzyme was absent in PB12 and PB13, in the wild type it was 7.7%. Finally, it was found that in the JM101 and PB12 strains both the oxidative and the nonoxidative branches of the pentose phosphate pathway contributed to ribose 5-phosphate synthesis, whereas in PB13 this pentose was synthesized almost exclusively through the oxidative branch. The determined carbon fluxes correlate with biochemical and genetic characterizations.
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Affiliation(s)
- S Flores
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, 62250 Cuernavaca, México
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Avilan L, Gontero B, Lebreton S, Ricard J. Memory and imprinting effects in multienzyme complexes--I. Isolation, dissociation, and reassociation of a phosphoribulokinase-glyceraldehyde-3-phosphate dehydrogenase complex from Chlamydomonas reinhardtii chloroplasts. EUROPEAN JOURNAL OF BIOCHEMISTRY 1997; 246:78-84. [PMID: 9210468 DOI: 10.1111/j.1432-1033.1997.00078.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
A bienzyme complex made up of phosphoribulokinase and glyceraldehyde-3-phosphate dehydrogenase has been isolated and purified from chloroplasts of Chlamydomonas reinhardtii. The complex contains four phosphoribulokinase and eight glyceraldehyde-3-phosphate dehydrogenase polypeptide chains. As phosphoribulokinase is dimeric and glyceraldehyde-3-phosphate dehydrogenase tetrameric, it is concluded that the complex comprises two phosphoribulokinase and two glyceraldehyde-3-phosphate dehydrogenase molecules. Its overall molecular mass is 460 kDa, which is in excellent agreement with its stoichiometry. Moreover, owing to the nature of the two enzymes, this complex must catalyse two nonconsecutive reactions. The bienzyme complex tended to spontaneously dissociate into the free enzymes upon dilution. This dissociation process was considerably promoted by reducing agents such as dithiothreitol or reduced thioredoxin. The kinetics of the dissociation process induced by dithiothreitol or reduced thioredoxin were paralleled by an increase of activity of phosphoribulokinase. The dissociation of the complex was reversible. If oxidized phosphoribulokinase and glyceraldehyde-3-phosphate dehydrogenase were mixed, a certain amount of the complex was formed. The reconstituted complex displayed properties that were indistinguishable from those of the native complex extracted from chloroplasts of Chlamydomonas reinhardtii. These results suggest that the concentration of the complex in vivo must vary depending on the light intensity.
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Affiliation(s)
- L Avilan
- Institut Jacques Monod, Université Paris VII, France
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Korzeniewski B, Quant PA. A simple mechanism decreasing free metabolite pool size in static spatial channelling. Mol Cell Biochem 1997; 169:135-42. [PMID: 9089640 DOI: 10.1023/a:1006882029611] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
We propose a simple mechanism which enables decrease of the free pool of channelled metabolite in static spatial channelling, when the concentration of the enzyme consuming the channelled metabolite is greater than the concentration of the enzyme producing this metabolite. Spatial channelling occurs between two enzymes when the common metabolite is released to a small space between these enzymes and does not from a ternary covalent complex with them, as is the case in covalent (dynamic or static) channelling. The mechanism proposed is qualitatively independent of rate constants, metabolite concentrations as well as other kinetic properties and is quantitatively significant for all physiologically relevant conditions. Calculations show that the free metabolite pool must decrease, when the concentration of the enzyme consuming the channelled metabolite is greater than the enzyme producing it. This mechanism is much more effective than increase in the concentration (or rate constant) of the enzyme consuming the metabolite in the absence of spatial channelling.
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Affiliation(s)
- B Korzeniewski
- Department of Biochemistry, University of Cambridge, England
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Abstract
The enzymic stages of mammalian mitochondrial beta-oxidation were elucidated some 30-40 years ago. However, the discovery of a membrane-associated multifunctional enzyme of beta-oxidation, a membrane-associated acyl-CoA dehydrogenase and characterization of the carnitine palmitoyl transferase system at the protein and at the genetic level has demonstrated that the enzymes of the system itself are incompletely understood. Deficiencies of many of the enzymes have been recognized as important causes of disease. In addition, the study of these disorders has led to a greater understanding of the molecular mechanism of beta-oxidation and the import, processing and assembly of the beta-oxidation enzymes within the mitochondrion. The tissue-specific regulation, intramitochondrial control and supramolecular organization of the pathway is becoming better understood as sensitive analytical and molecular techniques are applied. This review aims to cover enzymological and organizational aspects of mitochondrial beta-oxidation together with the biochemical aspects of inherited disorders of beta-oxidation and the intrinsic control of beta-oxidation.
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Affiliation(s)
- S Eaton
- Sir James Spence Institute of Child Health, Royal Victoria Infirmary, Newcastle-upon-Tyne, U.K
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Kholodenko BN, Sakamoto N, Puigjaner J, Westerhoff HV, Cascante M. Strong control on the transit time in metabolic channelling. FEBS Lett 1996; 389:123-5. [PMID: 8766813 DOI: 10.1016/0014-5793(96)00532-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
A suite of different characteristic times is used to describe the temporal behavior of a metabolic pathway. Here we focus on the 'transit' time, that is the average time it takes for a molecule, entering the steady-state pathway as a substrate, to exit the pathway as a product. We show that metabolic channelling results in dramatic changes in control exerted by pathway enzymes on the transit time. In an 'ideal' pathway a doubling of the enzyme concentrations halves the transit time. In a dynamic channel such an increase can reduce the transit time by a factor of four or more.
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Affiliation(s)
- B N Kholodenko
- Department de Bioquimica i Fisiologia, Universitat de Barcelona, Marti i Franques 1, Barcelona, Spain
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