Identification of Cobamide Coenzyme in Nodules of Symbionts & Isolation of the B12 Coenzyme From Rhizobium meliloti

Abstract

A survey was conducted to determine whether or not the nodules from several leguminous species and from alder and Ceanothus contain cobamide coenzyme(s). Appreciable amounts of cobamide coenzyme were detected in the nodules of alfalfa, soybeans, peas, beans and red clover by use of a cobamide coenzyme free preparation of glutamate isomerase as the assay system. Since R. meliloti contained greater quantities of coenzymes than other sources tested, this bacterium was cultured in a relatively large scale operation and the cobamide coenzyme was isolated in a highly purified form. From spectral properties, chromatographic characteristics and the activity of the isolated compound in relation to that of authentic cobamide coenzymes in the glutamate isomerase reaction, it was concluded that the cobamide coenzyme from R. meliloti is the 5,6-dimethylbenzimidazolylcobamide compound.