Uncharacterized acyl-CoA synthetase subfamily similar to Acetoacetyl-CoA synthetase
This uncharacterized acyl-CoA synthetase family (EC 6.2.1.16, or acetoacetate#CoA ligase or acetoacetate:CoA ligase (AMP-forming)) is highly homologous to acetoacetyl-CoA synthetase. However, the proteins in this family exist in only bacteria and archaea. AACS is a cytosolic ligase that specifically activates acetoacetate to its coenzyme A ester by a two-step reaction. Acetoacetate first reacts with ATP to form an acyl-adenylate intermediate, which then reacts with CoA to produce an acyl-CoA ester. This is the first step of the mevalonate pathway of isoprenoid biosynthesis via isopentenyl diphosphate. Isoprenoids are a large class of compounds found in all living organisms.