Question

Pyruvate can be converted to acetyl coA by the action of

• A. pyruvate dehydrogenase
• B. pyruvic acid decarboxylase
• C. lactate dehydrogenase
• D. both $1$ and $3$

Answer 1

Answer: (A)

pyruvate dehydrogenase

Answer 2

Pyruvate converts into acetyl $coA$ in the presence of pyruvate dehydrogenase enzyme complex. The pyruvate dehydrogenase complex is a multi-molecular aggregate of three enzymes - pyruvate decarboxylase, dihydrolipoyl transacetylase and dihydrolipoyl dehydrogenase. It also requires $Mg^{+2}$. This conversion is gateway step or link reaction between glycolysis and Krebs' cycle and acetyl $coA$ acts as the connecting link. The formation of acetyl $coA$ results in the production of $2$ molecules of $CO_2$ and $2$ molecules of $NADH_2$.