Pyruvate dehydrogenase
The pyruvate dehydrogenase complex is a complex of three enzymes inside the mitochondria: pyruvate decarboxylase, dihydrolipoyltransacetylase, and dihydrolipoyldehydrogenase. The complex works as a whole in the presence of coenzymes TPP, NAD+, lipoate in the form of lipoamide, FAD and coenzyme A. Pyruvate dehydrogenase catalyzes the oxidative decarboxylation of pyruvate with the binding of acetyl to TPP, dihydrolipoyltransacetylase catalyzes the transfer of acetyl from TPP via lipoamide to coenzyme A, and dihydrolipoyldehydrogenase regenerates lipoamide using FAD, from which FADH2 is formed, which regenerates in turn by NAD+, from which NADH + H+ is formed. The enzyme is inhibited by arsenic in the oxidation state of As(III) (arsenates,...), which blocks lipoamide.
