Acetyl-CoA

 Acetyl CoA (Acetyl coenzyme A) is a vital molecule which is needed in metabolism. It's job is to transport 2 carbon atoms, using a high-energy linkage, in biosynthesis of a larger molecule(s). The rest of the molecule is used as a recognition site for specific enzymes.

Acetyl CoA is used at the start the Kreb's cycle (Citric Cycle) where it is the product of the binding of CoA and pyruvate. This conversion of pyruvate into acetyl CoA consists of three steps: decarboxylation, oxidation, and transfer of the resultant acetyl group to CoA. The acetyl group then is transferred to oxaloacetate which forms citric acid, by the reaction of Oxaloacetate with acetyl CoA and Water, which then goes through a a series of oxidations to produce energy rich activated carrier molecules. It can also be fed directly into the Kreb's cycle via Beta-Oxidation, where fatty acids are oxidised into Acetyl CoA, the process is carried out in peroxisomes and then resulting Acetyl CoA is expelled into cytosol.