A salt or ester of pyruvic acid.
active p. an intermediate formed in the oxidative decarboxylation of pyruvate. Cf. p. dehydrogenase (lipoamide). a-lactyl-thiamin pyrophosphate;
p. carboxylase ligase catalyzing reaction of ATP, p., and HCO32-, to form ADP, inorganic phosphate, and oxaloacetate; biotin and acetyl-CoA are involved; an absence of this enzyme results in neuronal loss in the cerebral cortex, leading to mental retardation.
p. decarboxylase a-carboxylase; a-ketoacid carboxylase;a carboxylase of yeast catalyzing decarboxylation of a 2-oxoacid (e.g., p.) to an aldehyde (e.g., acetaldehyde) without oxidoreduction and without lipoamide, in contrast to p. dehydrogenase (lipoamide); thiamin pyrophosphate dependent.
p. dehydrogenase a structurally distinct collection of enzymes containing p. dehydrogenase (lipoamide), dihydrolipoyl transacetylase, and dihydrolipoyl dehydrogenase.
p. dehydrogenase (cytochrome) an oxidoreductase catalyzing reaction between ferricytochrome b1 and p. to yield acetate and CO2, and ferrocytochrome b1.
p. dehydrogenase (lipoamide) an oxidoreductase catalyzing conversion of p. and (oxidized) lipoamide to CO2 and S6-acetyldihydrolipoamide in two successive reactions: the first between p. and thiamin pyrophosphate to yield CO2 and a-hydroxyethylthiamin pyrophosphate (active p.); the second between the last named and lipoamide to regain the thiamin pyrophosphate and yield S6-acetylhydrolipoamide. Cf. a-ketodecarboxylase.
p. kinase (PK) phosphoenolpyruvate kinase;a phosphotransferase catalyzing transfer of phosphate from phosphoenolpyruvate to ADP, forming ATP and p.; other nucleoside phosphates can participate in the reaction; a key step in glycolysis; a deficiency in p. kinase will lead to hemolytic anemia.
p. oxidase [EC 188.8.131.52] an oxidoreductase catalyzing the reaction of p., phosphate, and O2 to yield acetyl phosphate, CO2, and H2O2.
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