Abstract
The kinetic V/K isotope effect upon peroxidation of (1R)-[1-2H1]ethanol by [rat] liver catalase was studied by using a radiochemical assay with both 3H and 14C as tracers. The value of 1.9 found is in agreement with the value of 2.52 for peroxidation of (1R)-[1-3H1]ethanol according to the Swain equation. There was no isotope effect on Vmax, the maximal rate of peroxidation of (1R)-[1-2H1]ethanol, at rates of H2O2 generation/catalase heme up to 500 min-1. Even at rates 20-fold higher, the isotope effect on Vmax may not differ from 1.