Biosynthesis of vitamin B12: isolation of 15,23-dihydrosirohydrochlorin, a biosynthetic intermediate: structural studies and incorporation experiments

Abstract

An enzyme system from the vitamin B12 producer Propionibacterium shermanii converts uro'gen-III(2) into 15,23-dihydrosirohydrochlorin (7), the structure being established by 1H and 13C n.m.r. spectroscopy; this dihydro-macrocycle is enzymically converted into cobyrinic acid (6).