(acetyl coenzyme A) A compound consisting of acetyl combined through a sulphur bridge with *coenzyme A
. The formation of acetyl CoA is an energy-requiring reaction, involving the conversion of ATP to AMP and pyrophosphate. Acetyl CoA plays a central role in intermediary metabolism. It is a product of the degradation of fatty acids, carbohydrates, and some amino acids. It is an essential precursor in the TCA and glyoxylate cycles and is the starting point for the synthesis of fatty acids, terpenes, and some amino acids.