Biosynthesis of vitamin B12: mechanistic studies on the transfer of a methyl group from C-11 to C-12 and incorporation of 18O

Abstract

The transfer of a methyl group from C-11 to C-12 in vitamin B12 biosynthesis is shown, by a crossover experiment involving [1,11,17-(CD3)3]-labelled precursors, to occur in an intramolecular fashion; it is found that in Pseudomonas denitrificans, unlike Propionibacterium shermanii, no exchange of the ring A acetate oxygen atoms occurs during formation of the corrin ring.