Polyketides relationship between polyketide

Fig. 2a-d. The major architectural paridigms of fatty acid and polyketide synthases. Relationships between genes encoding a bacterial aromatic polyketide synthases, b eukaryotic fatty acid synthases and fungal polyketide synthases, c modular polyketide synthases, and d plant polyketide synthases... 

An additional problem is that polyketide formation requires acetyl-CoA, malonyl-CoA, and NADPH generated by primary metabolic pathways. These precursors and the cofactor are also used for fatty acid biosynthesis. An inverse relationship between the synthesis of fatty acids and polyketide compounds has been found in the mevinolin (lovastatin)-producing species ot Aspergillus (Dutton, 1988 Greenspan and Yudkovitz, 1985). Thus, any regulatory factor that substantially alters the rate or extent of formation of these precursors and cofactor may affect polyketide formation. 

Figure 3. Relationship between polyketide and fatty acid biosynthesis. The simplest ( minimaV) PKSs possess ketosynthase activity and produce linear polyketide products. In contrast, FASs also catalyze successive ketoreduction-dehydration-enoyl reduction reactions following each condensation. Diverse PKSs may perform none, part, or all of this reductive sequence. KS, ketosynthase KR, ketoreductase DH, dehydratase ER, enoyl reductase.

Scheme 67. Biogenetic relationships between polyketides from Aphyllophorales...

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