Coα/Coβ-Isomerie der am Kobalt methylierten Corrinoide. Über die CD-und ORD-Spektren einiger Isomerenpaare / Coα/Coβ-Isomerism of the Cobalt Methylated Corrinoids. CD and ORD Spectra of Several Isomer Pairs
Open Access
- 1 August 1981
- journal article
- research article
- Published by Walter de Gruyter GmbH in Zeitschrift für Naturforschung C
- Vol. 36 (7-8) , 497-505
- https://doi.org/10.1515/znc-1981-7-801
Abstract
The CD and ORD spectra of the Coar-and Co/β-methyl isomers of cobalamin, 2-methylthio-adenyl cobamide (factor S), cobyric acid and p-kresyl cobamide (factor lb) were recorded in water and acidic solution. In complete and incomplete (nucleotide free) (Coar-methyl)-corrinoids the axial ligands CH3 and H2O are unalterable (fixed) within a wide range of pH (about 1 to 12) at room temperature in the dark. Thus the spectra in this pH range are constant at X > 350 nm; spectral differences at X < 350 nm are effects of the nucleotide bases. The spectra of complete "base-on" (Co/β-methyl)-corrinoids are, like the spectra of (Coa-methyl)-corrinoids, at X > 350 nm not dependent on the nucleotide base. If the nucleotide base is not coordinated ("base-off'), the spectra change strikingly and at X > 350 nm are nearly identical with those of incomplete corrinoids e. g. cobyric acid.Keywords
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