Aflatoxins polyketide formation

Unlike primary metabolites, the genes that regulate the formation of the enzymes of seeondary metaboUte biosynthesis are often clustered. In several eases the loei of these genes have been determined. This has considerable sig-nifieanee in the control of secondary metabolite biosynthesis. The genes that eode for several important polyketide pathways such as those leading to the aflatoxins and the statins have been identified. Similar work has also been reported for penicillin biosynthesis and some non-ribosomal peptides as well as terpenoid pathways such as that leading to the gibberellins. 

Various studies have determined that aflatoxins are synthesized in two stages from malonyl CoA, first with the formation of hexanoyl CoA, followed by formation of a decaketide anthraquinone. Two fatty acid synthases (FAS) and a polyketide synthase (PKS) are involved in the synthesis of polyketide from the primary... 

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