3.5.3 Oxidation of Pyruvate to Acetyl CoA

3.5.3 Oxidation of Pyruvate to Acetyl CoA

Pyruvate derived from glucose by glycolysis, is oxidatively decarboxylated to acetyl-CoA before entering into citric acid cycle.

The reaction is catalysed by multiple enzyme complex pyruvate dehydrogenase, located in the mitochondria. Thiamine pyrophosphate, coenzyme A, lipoic acid and NAD+ are coenzymes needed for the reaction. The acetyl CoA is fed into citric acid cycle and oxidized to CO2 in citric acid cycle. The NADH+H+ is reoxidised to NAD+ via electron transport chain in mitochondria and during this 3 molecules of ATP are synthesized. Four different vitamins required in human nutrition are vital components of this system: thiamine (inTPP), riboflavin (in FAD), niacin (in NAD) and pantothenete (in CoA). The acetyl CoA is fed into citric acid cycle and oxidized to CO2 in citric acid cycle. The NADH+H+ is reoxidised to NAD+ via electron transport chain in

mitochondria and during this 3 molecules of ATP are synthesized.

Pyruvate dehydrogenase

CH3COCOOH+ NAD++ CoA-SH CH3 COS~CoA+ NADH+H++ CO2

Pyruvate   Acetyl CoA

Last modified: Saturday, 31 March 2012, 5:59 AM