Ketoacyl synthase
![Cartoon representation of the molecular structure of protein registered with 1mzj code.[1]](/Images/godic/202501/22/PDB_1mzj_EBI3243.jpg")
![The proposed naphthomycin A biosynthetic pathway.1 A, adenylation; KS, ketosynthase; AT, acyltransferase; T, acyl carrier protein or peptidyl carrier protein; DH, dehydratase; KR, ketoreductase; (*) redundant domain.](/Images/godic/202501/22/page1-220px-Naphthomycin_A_2.pdf3243.jpg")
A keto-synthase (KS) is a domain of polyketide synthases with a thiol (SH) group on a cysteine side-chain. Every polyketide synthase module has an acyl carrier protein (ACP) and a ketosynthase domain that collaborate to catalyze the chain elongation.