In the cycle, pyruvate is decarboxylated and reacts with coenzyme A to form acetyl-CoA. The enzyme that catalyzes this reaction is pyruvate-dehydrogenase. Acetyl-CoA condenses with a four-carbon acid, oxalic acetate, to form citrate, a six-carbon acid, as well as a variety of other organic acid-intermediaries (Walker, 1998c). Under fermentative conditions, decarboxylation of pyruvate to acetyl CoA is inactive. One completed citric acid cycle generates two molecules of carbon dioxide and also regenerates oxalic acetate.