What is pyruvate


Pyruvate, the anion of pyruvic acid. P. is an important branching point in the anaerobic and aerobic metabolism (Fig.).

Pyruvate synthesis. The synthesis of pyruvate takes place 1) in the glycolysis from phosphoenolpyruvate. As an enol ester, this contains an energy-rich bond which, when hydrolytically cleaved, releases 50.24 kJ (12 kcal). Through the catalysis of pyruvate kinase, this energy is used to transfer the phosphate residue to adenosine diphosphate with the synthesis of adenosine triphosphate. 2) in the metabolism of certain amino acids, especially through the transamination of alanine, the oxidative deamination of serine and the desulfhydration of cysteine.

Pyruvate metabolism. The sales des P. takes place 1) in the anaerobic glycolysis to lactate, 2) in the anaerobic alcoholic fermentation to ethanol, 3) under aerobic conditions by means of the pyruvate dehydrogenase complex by oxidative decarboxylation to acetyl coenzyme A. This process is for the linkage different metabolic pathways are particularly important.

Balance sheet the oxidative decarboxylation of P .: CH3COCOO- (Pyruvate) + HSCoA (coenzyme A) + NAD+ → CH3CO-SCoA (Acetyl Coenzyme A) + CO2 + NADH + H+. With complete oxidation via the tricarboxylic acid cycle, 15 molecules of ATP are formed from one molecule of pyruvate (14 by respiratory chain phosphorylation and 1 by substrate chain phosphorylation).

4) in the carboxylation by various enzyme systems to oxaloacetate. This reaction is the starting point for gluconeogenesis.

5) in nitrogen fixation, in pyruvate a phosphoroclastic cleavage into acetyl phosphate and CO2 subject.