Kinetic study of the reaction of ebselen with peroxynitrite

Abstract
The second-order rate constant for the reaction of ebselen with peroxynitrite (ONOO) is (2.0±0.1) × 106 M−1s−1 at pH ≥ 8 and 25°C, 3–4 orders of magnitude higher than the rate constants observed for cysteine, ascorbate, or methionine. The activation energy is relatively low, 12.8 kJ/mol. This is the fastest reaction of peroxynitrite observed so far. It may allow Secontaining compounds to play a novel role in the defense against peroxynitrite, one of the important reactive species generated during inflammatory processes.