| Irreversible transitions in a model substrate cycle. An experimental illustration. | |
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MedLine Citation:
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PMID: 2139855 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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In a previous article [(1987) J. Theor. Biol, 127, 439-449], the dynamic behavior of a simple substrate cycle, bounded by moiety conservation, and in which one of the two antagonist enzymes is subjected to a destabilizing factor, was investigated. Depending upon the control parameter chosen, that is, the total interconverted substrate concentration and the ratio of the interconverting enzyme maximal activities, monostability, reversible (hysteresis) and/or irreversible transitions could be observed. In the present work, we report experiments dealing with the moiety ATP/ADP interconverted by enzymes phosphofructokinase (PFK) and pyruvate kinase (PK). The cycle operates under conditions where (1) PFK is inhibited by excess of its substrate, ATP, and (2) both enzymes are working under zero-order kinetics for their respective cosubstrates F6P and PEP. Under conditions where the PK maximal activity is lower than the PFK optimal activity, irreversible transitions from a high ATP (resp. low ADP) steady-state concentration to a lower (resp. higher) one, are observed when varying the total moiety (ATP + ADP) concentration. A graphical interpretation of the observed behavior is given. Plausible biochemical consequences of this phenomenon are also emphasized. |
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Authors:
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A Cimino; J F Hervagault |
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Publication Detail:
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Type: Journal Article |
Journal Detail:
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Title: FEBS letters Volume: 263 ISSN: 0014-5793 ISO Abbreviation: FEBS Lett. Publication Date: 1990 Apr |
Date Detail:
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Created Date: 1990-06-11 Completed Date: 1990-06-11 Revised Date: 2003-11-14 |
Medline Journal Info:
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Nlm Unique ID: 0155157 Medline TA: FEBS Lett Country: NETHERLANDS |
Other Details:
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Languages: eng Pagination: 199-205 Citation Subset: IM |
Affiliation:
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Unité de Recherche Associée no. 523, Université de Compiègne, France. |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Adenosine Diphosphate
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metabolism Adenosine Triphosphate / metabolism Animals Chromatography, High Pressure Liquid Enzyme Induction Kinetics Models, Chemical Muscles / enzymology Phosphofructokinase-1 / metabolism Pyruvate Kinase / metabolism Rabbits Substrate Cycling / physiology* |
| Chemical | |
Reg. No./Substance:
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56-65-5/Adenosine Triphosphate; 58-64-0/Adenosine Diphosphate; EC 2.7.1.11/Phosphofructokinase-1; EC 2.7.1.40/Pyruvate Kinase |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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