Selective inactivation of glyceraldehyde-3-phosphate dehydrogenase by vinyl sulfones

Incubation of glyceraldehyde-3-phosphate dehydrogenase with vinyl sulfones resulted in a pseudo first-order loss of enzyme activity. The selective inactivation of the enzyme by vinyl sulfones is suggested from the structural requirement analysis and the enzyme susceptibility test. The enzyme inactivation was strongly reduced in the presence of NAD or glyceraldehyde-3-phosphate, and the prior treatment of the enzyme with 5,5'-dithio-bis-(2-nitrobenzoic acid) prevented the enzyme from the inactivation by vinyl sulfones (> or = 90%). Moreover, the early rapid phase of inactivation was much more responsive to L-cysteine reactivation, compared with the slower phase. Based on these results, it is proposed that vinyl sulfones inactivate the enzyme by inducing the oxidation of cysteine residue and/or covalent binding to cysteine residue in active site.