Studies on the biosynthesis of vitamin B sub 2 and vitamin B sub 12
Feeding experiments with Ashbya gossypii followed by NMR analysis of the resulting riboflavin showed incorporation of deuterium from D-(2-{sup 2}H)ribose at C-2{prime} and from D-(1-{sup 2}H)ribose in the pro-R position at C-1{prime} of the ribityl side chain. The results rule out an Amadori rearrangement mechanism for the reduction of the ribosylamino to the ribitylamino linkage and point to formation of a Schiff base that is reduced stereospecifically opposite to the face from which the oxygen has departed. As prerequisite for the analysis, the {sup 1}H NMR signals for the pro-R and pro-S hydrogens at C-1{prime} of riboflavin and its tetraacetate were assigned with the aid of synthetic stereospecifically deuteriated samples. Feeding experiments with Propionibacterium shermianii followed by NMR analysis of the resulting vitamin B{sub 12} showed: (1) 5-methylbenzimidazole (5MBI) incorporated and only one regioisomer (B6-demethylcyanocobalamin)formed. (2) 8-demethylriboflavin incorporated and the same regioisomer was obtained as 5MBI experiment. (3) (1{prime}-{sup 13}C, 5-{sup 15}N)riboflavin incorporated and {sup 13}C-NMR showed that {sup 13}C at the B2 position of cyanocobalamin coupled to both adjacent nitrogen-15 atoms at about the same ratio.
- Research Organization:
- Ohio State Univ., Columbus, OH (USA)
- OSTI ID:
- 7165272
- Resource Relation:
- Other Information: Thesis (Ph. D.)
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
VITAMIN B GROUP
BIOSYNTHESIS
VITAMIN B-12
BACTERIA
CARBON 13
DEUTERIUM
NITROGEN 15
NMR SPECTRA
SCHIFF BASES
TRACER TECHNIQUES
CARBON ISOTOPES
DRUGS
EVEN-ODD NUCLEI
HEMATINICS
HEMATOLOGIC AGENTS
HYDROGEN ISOTOPES
IMINES
ISOTOPE APPLICATIONS
ISOTOPES
LIGHT NUCLEI
MICROORGANISMS
NITROGEN ISOTOPES
NUCLEI
ODD-EVEN NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
SPECTRA
STABLE ISOTOPES
SYNTHESIS
VITAMINS
550201* - Biochemistry- Tracer Techniques