[Role of sulfhydryl groups in the inactivation mechanism of bacterial formate dehydrogenase].

Inactivation of formate dehydrogenase (EC 1.2.1.2) from gramnegative methanol-utilizing bacteria was studied. It was shown that the thermal inactivation of the enzyme occurs at temperatures above 50 degrees; at temperatures below 40 degrees the inactivation is due to metal ion-catalyzed oxidation of its sulfhydryl groups. A possible general mechanism of the enzyme inactivation is proposed.