title: Biosynthesis of vitamin B12: concerning the origin of the methine protons of the corrin nucleus.
abstract: 13C NMR spectroscopy has been used to locate six deuterium atoms incorporated biosynthetically on the periphery of the corrin nucleus of vitamin B12 (cyanocobalamin) derived from cells of Propionibacterium shermanii grown in a medium containing 50% 2H2O and 13C-enriched delta-aminolevulinic acid. The implications of these results for the mechanism of vitamin B12 biosynthesis are discussed, and it is concluded that the same oxidation level of the intermediates is maintained throughout the biosynthetic pathway, from delta-aminolevulinic acid to corrin.
mesh_terms: D002247:Carbon Isotopes; D045728:Corrinoids; D003903:Deuterium; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D011424:Propionibacterium / Q000378:metabolism*; D014805:Vitamin B 12 / Q000096:biosynthesis*
chemical_list: D002247:Carbon Isotopes; D045728:Corrinoids; D003903:Deuterium; D014805:Vitamin B 12