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A novel form of vitamin B-12 and its derivatives
Journal article   Peer reviewed

A novel form of vitamin B-12 and its derivatives

Motomi Katada, Somdev Tyagi, Amar Nath, Richard L. Petersen and Raj K. Gupta
Biochimica et biophysica acta. General subjects, v 584(1)
1979
DOI: https://doi.org/10.1016/0304-4165(79)90245-9

Abstract

Cobalamin isomer Mössbauer Vitamin B-12 derivative
A new isomeric form of cobalamins is reported. The conversion of cobalamin to cobalamin′ (the new form) is achieved by substituting the benzimidazole base by a less bulky group like H 2O of CN − and modest thermal treatment. The back conversion of adenosylcobalamin′ to the corresponding regular form occurs in the ‘base-off’ form at room temperature. It seems that the corrin ring becomes quite flexible in the ‘base-off’ form and the freer axial movement of the cobalt atom flips the corrin ring into a different conformation. The change in conformation is borne out by subtle changes in the proton magnetic resonances on the corrin ring and the base, and very marked variation in the emission Mössbauer spectra. The latter is indicative of appreciable changes in the spatial conformation in the immediate vicinity of the central metal atom. The ultraviolet-visible and infrared spectra of a cobalamin′ are indistinguishable from those of its corresponding regular form. The new conformational isomeric species is present as an impurity in all commercially available cobalamins (including pharmaceutical preparations). It raises the question whether the cobalamins′ constitute the real biologically active anti-anemic factor in humans

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