Pyruvate which is produced in the cytosol during glycolysis is transported to mitochondria for further oxidation. It is imported by a transport protein along with H+.Acetyl CoA is formed from pyruvate by its oxidative decarboxylation by the enzyme pyruvate dehydrogenase, which is a large multi-enzyme complex that catalyzes 5 reactions. These reactions involve 5 different coenzymes — thiamine pyrophosphate (TPP), lipoamide, coenzyme A, FAD and NAD+. The overall reaction can be given as follows: