What is the process by which pyruvate transforms into acetyl CoA?

The transformation of pyruvate into acetyl CoA occurs through a specific process known as oxidative decarboxylation. During this reaction, pyruvate, which is a 3-carbon molecule, undergoes a decarboxylation reaction where one carbon atom is removed in the form of carbon dioxide (CO2). This reduction in carbon count results in a 2-carbon molecule, which is then attached to coenzyme A, forming acetyl CoA.

This process takes place in the mitochondrial matrix and involves the enzyme pyruvate dehydrogenase complex, which also facilitates the conversion of NAD+ into NADH. The formation of acetyl CoA is a critical step, as it links glycolysis to the citric acid cycle, allowing the 2-carbon acetyl group to enter the cycle and be further oxidized for energy production.

Oxidative phosphorylation, fermentation, and reversible decarboxylation do not accurately describe this transformation, as they pertain to different metabolic processes. Oxidative phosphorylation is involved in ATP production through the electron transport chain; fermentation is an anaerobic process that converts pyruvate into other products like ethanol or lactate; and reversible decarboxylation refers to processes that are not