Isolation of 57Co-cobalamin coenzymes at high specific activity from Streptomyces griseus

The distribution of radio-labelled cobalamins in Streptomyces griseus grown in medium containing 57Co-cobalt chloride has been estimated by two-dimensional thin-layer chromatography and bioautography. 57Co-Methylocobalamin (Me[57Co]Cbl) was the major form in the mycelium together with smaller amounts of 57Co-adenosylcobalamin (Ado[57Co]Cbl) and 57Co-hydroxocobalamin (OH[57Co]Cbl). The OH[57Co]Cbl was detected in three forms having, respectively, anionic, cationic and neutral properties. A simple technique has been developed to isolate and purify Me[57Co]Cbl and Ado[57Co]Cbl from the mycelium using column chromatography on ion-exchange celluloses. Small quantities of each cobalamin coenzyme have been obtained at 90--96% purity and specific activities of 190--230 muCi/microgram.