Ketoacyl synthase
![Cartoon representation of the molecular structure of protein registered with 1mzj code.[1]](/uploads/202501/22/PDB_1mzj_EBI3243.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.