Polyketide synthase; part of the Caz gene cluster that mediates the biosynthesis of the azaphilones chaetoviridin A and chaetomugilin A (PubMed:26172141, PubMed:23072467). The substrate (S,E)-4-methyl-hex-2-enoyltriketide is transferred from the CazF acyl carrier protein domain to the CazM N-terminal acylcarrier protein (ACP) transacylase domain, and from there to the phosphopantetheinyl group of the CazM ACP domain, where it serves as a starter for the biosynthesis of cazaldehyde A, the precursor of chaetoviridin A and chaetomugilin A. During this process, CazM consumes malonyl-CoA, S-adenosyl-L-methionine and NADPH to catalyze four rounds of chain elongation, cyclization and ultimately NADPH-dependent product release (PubMed:26172141). Binds 1 phosphopantetheine covalently. Polyketide biosynthesis. Multidomain protein; including an N-terminal starter unit:ACP transacylase (SAT) domain, a beta-ketoacyl synthase (KS) domain, a malonyl-CoA:ACP transacylase (MAT) domain, a product template domain, a acyl carrier protein (ACP) domain, a methyltransferase domain and a reductive NADPH-binding domain that is required for NADPH-dependent product release. Abolishes the production of azaphilones.