pyruvate

Left: pyruvic acid -click to enlarge image.

Pyruvate is the carboxylate anion of the alpha-keto acid. As the output compound of glycolysis, where one molecule of glucose yields 2 pyruvate, pyruvate is an important intermediate in metabolism. Pyruvic acid unites several key metabolic reactions because it can be converted to carbohydrates via gluconeogenesis, to fatty acids, to energy through acetyl-CoA, to the amino acid alanine, and to ethanol.

Provided that sufficient O2 is available, pyruvic acid is converted to acetyl-CoA, which enters the Krebs cycle. Pyruvate is also converted to oxaloacetate in an anaplerotic reaction, and ultimately yields 4 molecules of CO2.

In anaerobic conditions, pyruvic acid is converted to lactic acid and ethanol by plants. Pyruvate generated by glycolysis is converted by anaerobic respiration (lactate fermentation) to lactate using the enzyme lactate dehydrogenase and the coenzyme NADH. Pyruvate is converted, in alcoholic fermentation, to acetaldehyde and then to ethanol.