Paracatalytic inactivation of pyruvate decarboxylase in the presence of quinones

Pyruvate promotes the yeast pyruvate decarboxylase inactivation under the influence of substituted p-benzoquinones. Pyruvate decarboxylase activity is not renewed after the removal of low-molecular impurities by gel filtration and subsequent addition of dithiothreitol, thiamine diphosphate, magnesiu...

Full description

Saved in:
Bibliographic Details
Published inUkrainskij biohimičeskij žurnal Vol. 65; no. 2; p. 42
Main Authors Vovk, A I, Murav'eva, I V
Format Journal Article
LanguageRussian
Published Ukraine 01.03.1993
Subjects
Benzoquinones - chemistry
Catalysis
Chromatography, Gel
Decarboxylation
Hydrogen-Ion Concentration
Molecular Structure
Molecular Weight
Pyruvate Decarboxylase - antagonists & inhibitors
Saccharomyces cerevisiae - enzymology
Online AccessGet more information

Cover

More Information
Summary:Pyruvate promotes the yeast pyruvate decarboxylase inactivation under the influence of substituted p-benzoquinones. Pyruvate decarboxylase activity is not renewed after the removal of low-molecular impurities by gel filtration and subsequent addition of dithiothreitol, thiamine diphosphate, magnesium chloride. The inactivation rate under joint action of 2-methyl-5-isopropyl-p-benzoquinone and pyruvate is regulated by the pseudo-first-order equation. The relationship between pseudo-first-order rate constant and pyruvate concentration takes the shape of hyperbola. The inactivation order with respect to quinone is determined by oxidant concentration and pH value. Maximum pseudo-first-order rate constant values in the presence of the excess substrate and 2-methyl-5-isopropyl-p-benzoquinone are observed at pH 5.9-6.0. The data obtained evidence for the fact that during inactivation quinone interacts with "active acetaldehyde" being the intermediate in the process of catalysis with pyruvate decarboxylase.
ISSN:0201-8470