Abstract
Kinetic studies are reported on the catalysis of tritium exchange from meso-2,3-ditritiosuccinate to water by solu- ble succinic dehydrogenase from bovine heart. Tritium exchange does not proceed for the most part via the equilibrium dismutation of succinate and fumarate; rather, exchange appears to proceed directly from an enzyme-succinate complex.
Time-dependent changes in the exchange activity were observed in the presence of fumarate. Fumarate and fumarate analogues can either enhance or inhibit the exchange reaction depending on concentration and other conditions. Oxygen enhances the exchange rate several-fold in an easily reversible manner which cannot be attributed to the autoxidation of succinate.