Purification and characterization of a novel enoyl coenzyme A reductase from Streptomyces collinus

A novel NADPH-dependent enoyl reductase, catalyzing the conversion of 1- cyclohexenylcarbonyl coenzyme A (1-cyclohexenylcarbonyl-CoA) to cyclohexenylcarbonyl-CoA, was purified to homogeneity from Streptomyces collinus. This enzyme, a dimer with subunits of identical M(r) (36,000), exhibits a K(m) of 1.5 ± 0.3 μM for NADPH and 25 ± 3 μM for 1- cyclohexenylcarbonyl-CoA. It has a pH optimum of 7.5, is most active at 30°C, and is inhibited by both divalent cations and thiol reagents. Two internal peptide sequences were obtained. Ansatrienin A (an antibiotic produced by S. collinus) contains a cyclohexanecarboxylic acid moiety, and it is suggested that the 1-cyclohexenylcarbonyl-CoA reductase described herein catalyzes the final reductive step in the conversion of shikimic acid into this moiety.