2.3.1.161 additional information expression of minimal polyketide synthase domains of subunit LovB as standalone proteins. The didomain proteins ketosynthase-malonyl-coenzyme A:acyl carrier protein acyltransferase KS-MAT can transfer the acyl group to both the cognate LovB acyl carrier protein and heterologous acyl carrier proteins from bacterial type I and type II polyketide synthases. It transfers malonyl and acetyl groups with kcat/Km values of 0.62 per min and 0.032 per min, resp 2.3.1.161 S208A LovB MAT mutant 2.3.1.161 S209A LovB MAT mutant 2.3.1.161 S656A inactivation of malonyl-coenzyme A:acyl carrier protein acyltransferase domain in ketosynthase-malonyl-coenzyme A:acyl carrier protein acyltransferase for assay of ketosynthase activity. Ketosynthase displays no activity towards acetyl groups but recognizes malonyl groups in the absence of cerulenin 2.3.1.161 S656A LovB KS-MAT mutant, MAT domain inactivated