Coenzyme A thiosulfonate (coenzyme A disulfide-S,S-dioxide), an affinity analog of coenzyme A

Abstract

The structure of the CoA affinity analog-oxidized CoA disulfide (o-CoAS2) (Collier, G. E., and Nishimura, J. S. (1978) J. Biol. Chem. 253, 4938-4939) has been deduced to be that of the thiosulfonate of CoA, i.e. coenzyme A disulfide-S,S-dioxide. This deduction is based on several considerations among which are: the cleavage of o-CoAS2 by dithiothreitol under anaerobic conditions to equimolar amounts of CoASH and CoASO2H; the alkali-catalyzed dismutation of 3 mol of o-CoAS2 to 4 mol of CoASO2H and 1 mol of CoA disulfide; and comparison of the 13C-NMR spectra of CoA disulfide and o-CoAS2. The results of studies with Clostridial phosphotransacetylase (EC 2.3.1.8) and pigeon muscle carnitine acetyltransferase (EC 2.3.1.7) were consistent with the action of o-CoAS2 as a CoA affinity analog on these enzymes. Inactivation was characterized by what appeared to be disulfide bonding between CoA and important sulfhydryl groups of the proteins.