Zur Koordinations-Isomerie (a-b-Isomerie) der Co-Alkyl-corrinoide

Open Access
Publisher Website
Google Scholar
Abstract
Chromatography and electrophoresis of the reaction products from B12s and methyl iodide yield the known Co-methyl-cobalamin and a new light sensitive corrinoid compound. The latter is very probably Co-methyl-cobalamin a with the methyl group “down”. The absorption spectrum of this yellow corrinoid differs only slightly from that of Co-methyl-cobalamin in acid media and does not depend on pH at wavelengths higher than 300 nm. The new corrinoid is thermolabile and on heating at 95°C for several hours in O2-free aqueous medium changes nearly quantitatively to Comethyl-cobalamin. The last corrinoid, on the contrary, yields at 95 cC several per cents of Comethyl-cobalamin a. The reaction of B12s with dimethyl sulfate yields beyond the mentioned products Co-methyl-cobalamin Nm (yellow; the absorption spectrum does not depend on pH and is identical with that of Co-methyl-cobalamin in acid media) and B12Nm (both corrinoids have a methyl group on N-3 of the 5,6-dimethylbenzimidazole moiety). The thermal isomerization of both Co-methyl-cobalamins is in accord with the observed formation of Co-14CH3-cobinamide on heating of Co-14CH3-cobalamin with Co-CH3-cobinamide.

This publication has 0 references indexed in Scilit: