Mechanism of action of coenzyme B_(12). Release of 5′-deoxyinosine on incubation of deoxyinosylcobalamin, 1,2-propanediol and propanediol dehydrase

Abstract

We wish to report evidence that the covalent bond in coenzyme B_(12) between the cobalt atom and the methylene group (C-5′) of the nucleoside moiety is cleaved during enzymatic conversion of 1,2-propanediol to propionaldehyde. Acquisition of a third hydrogen satisfies the valence at C-5′ created by the cobalt-C-5′ bond cleavage; C-5′ is thus converted to a methyl group. The experimental result to support this assertion is the observation that mixtures of 1,2-propanediol, propanediol dehydrase and deoxyinosylcobalamin liberate 5′-deoxyinosine to solution.

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