The enzyme, found in both eukaryotes and in prokaryotes, is involved in degradation pathways such as fatty acid beta-oxidation. The enzyme acts on 3-oxoacyl-CoAs to produce acetyl-CoA and an acyl-CoA shortened by two carbon atoms. The reaction starts with the acylation of a nucleophilic cysteine at the active site by a 3-oxoacyl-CoA, with the concomitant release of acetyl-CoA. In the second step the acyl group is transferred to CoA. Most enzymes have a broad substrate range for the 3-oxoacyl-CoA. cf. EC 184.108.40.206, acetyl-CoA C-acetyltransferase.