Pyruvate dehydrogenase - Definition and Overview

Pyruvate dehydrogenase is an allosteric enzyme that transforms pyruvate into acetyl-CoA which is then used in the citric acid cycle.

It is inhibited when either of the three following ratios are increased: [ATP]/[ADP], [NADH]/[NAD+] and [acetyl-CoA]/[CoASH].

Pyruvate dehydrogenase is actually a big complex composed of 60 subunits: 24 pyruvate dehydrogenase (E1), 24 dihydrolipoyl transacetylase (E2) and 12 dihydrolipoyl dehydrogenase (E3).

The global reaction catalysed by pyruvate dehydrogenase is:

pyruvate + CoA + NAD⁺ ⇒ acetyl-CoA + NADH + H⁺ + CO₂