Isotope effect in peroxidation of deuterium-labelled ethanol by liver catalase

The kinetic V/K isotope effect upon peroxidation of (1R)-[1-2H1]ethanol by liver catalase was studied by using a radiochemical assay with both 3H ad 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’ [Swain, Stivers, Ruver & Schaad (1958) J. Am. Chem. Soc. 80, 5885-5893]. There was no isotope effect on V, the catalase haem up to 500 min-1. Even at rates 20-fold higher the isotope effect on V may not be different from 1. A detailed description of the synthesis of the 2H- and 3H-substituted ethanol compounds and the analysis of these has been deposited as Supplementary Publication SUP 50110 (5 pages) at the British Library Lending Division, Boston Spa, Wetherby, W. Yorkshire LS23 7BQ, U.K., from whom copies can be obtained on the terms indicated in Biochem. J. (1978) 169,5.