Polyketide synthase; part of the gene cluster that mediates the biosynthesis of asperfuranone, a probable antitumor agent. The polyketide synthase afoG is responsible for producing the 3,5-dimethyloctadienone moiety from acetyl-CoA, three malonyl-CoA, and two S-adenosyl methionines (SAM). The 3,5-dimethyloctadienone moiety is then loaded onto the SAT domain of afoE and extended with four malonyl-CoA and one SAM, which leads to the formation of 2,4-dihydroxy-6-(5,7-dimethyl-2-oxo-trans-3-trans-5-nonadienyl)-3-methylbenzaldehyde (compound 2) after reductive release and aldol condensation. AfoD is the next enzyme in the biosynthesis sequence and hydroxylates the side chain at the benzylic position of compound 2. After benzylic hydroxylation, a furan ring is formed after five-member ring hemiacetal formation and water elimination. AfoF and afoC are proposed to oxidize the R-diketone proton and to reduce the unconjugated carbonyl group, respectively, to generate asperfuranone. Since no intermediates could be isolated from afoF and afoC deletants, the sequence of these two enzymes is not fully understood. Moreover, since afoC deletant still produces a small amount of asperfuranone, other endogenous oxidoreductases might catalyze the same reaction with much less efficiency