Biosynthesis of the polyether antibiotic monensin-a: stereochemical aspects of the incorporation and metabolism of isobutyrate

Abstract

The incorporation of stereospecifically labelled isotopomers of isobutyrate into monensin-A provides stereochemical and mechanistic information about the bioconversion of isobutyrate into methylmalonyl-CoA and n-butyryl-CoA in Streptomyces cinnamonensis; a rearrangement of isobutyryl-CoA to n-butyryl-CoA occurs without loss of the α-hydrogen, and the carbonyl carbon migrates to the pro-(S) methyl group, and is replaced by a hydrogen atom with overall retention of configuration.