Enterocin has a caged, tricyclic,
nonaromatic core and its formation undergoes a flavoenzyme (EncM) catalyzed
Favorskii-like rearrangement of a poly(beta-carbonyl). Studies done on enterocin have shown that it is biosynthesized from a type II polyketide synthase (PKS) pathway, starting with a structure derived from
phenylalanine or activation of
benzoic acid followed by the EncM catalyzed rearrangement. The
enzyme EncN catalyzes the
ATP-dependent transfer of the benzoate to EncC, the
acyl carrier protein. EncC transfers the aromatic unit to EncA-EncB, the
ketosynthase in order for malonation via FabD, the
malonyl-CoA:ACP transacylase. A
Claisen condensation occurs between the benzoyl and malonyl groups and occurs six more times followed by reaction with EncD, a ketoreductase; the intermediate undergoes the EncM catalyzed oxidative rearrangement to form the enterocin tricyclic core. Further reaction with
O-methyltransferase, EncK and
cytochrome P450 hydroxylase, EncR yields enterocin. == References ==