Pyruvic acid generated in the cytosol, is transported to mitochondria, and before it enters Kreb's cycle, operative in mitochondria, one of the three carbon atoms of pyruvic acid is oxidised to carbon dioxide in a reaction called oxidative decarboxylation.
(i) Pyruvate is first decarboxylated and then oxidised by the enzyme pyruvate dehydrogenase.
(ii) The remaining 2-carbon acetate unit is readily accepted by a sulphur containing compound, Coenzyme A to form acetyl coenzyme A.
