Studies on the biosynthesis of corrinoids and porphyrinoids. III. The origin of amide nitrogen of vitamin B12.

Abstract

To clarify the origin of amide-nitrogen of vitamin B12, [1-13C]aminolevulinic acid (ALA) and L-[amide-15N]glutamine were administered to P. shermanii. The 13C-nuclear magnetic resonance spectrum of the vitamin B12 subsequently isolated showed distinct 13C-15N coupling and isotope shift at six amide carbons. However, the C-57 amide carbon showed neither coupling, nor shift. Thus, it was concluded that the nitrogens of 6 amides of the side chain were derived from glutamine and the C-57 amide nitrogen was from threonine.