Which carbon atom(s) of pyruvate is(are) first converted to carbon dioxide by pyruvate dehydrogenase complex?
(a) the carboxylate carbon
(b) the carbonyl carbon
(c) the methyl carbon
(d) both carbons (a) and (c) in equal amounts

(A) The carboxylate carbon

Explanation:

Pyruvate is produced as a product of glycolysis in cytoplasm.

Pyruvate oxidation takes place in mitochondrial matrix. Here, these steps are followed:

Step 1. The carboxyl group of the pyruvate is snipped off and is released as a carbon dioxide.

Step 2. The molecule containing 2 carbons produced from the step 1 is oxidized, and the electrons lost in the oxidation are picked up by

Step 3. The oxidized two-carbon molecule gets attached to Coenzyme A and forms acetyl CoA.