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Updated: Aug 8, 2026

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Published on: February 7, 2018
Kinetic study of the reaction of glutathione peroxidase with peroxynitrite
K Briviba1, R Kissner, W H Koppenol
1Institut für Physiologische Chemie I, Heinrich-Heine-Universität D usseldorf, Postfach 101007, D-40001 Düsseldorf, Germany.
Abstract:
Glutathione peroxidases and their mimics, e.g., ebselen or diaryl tellurides, efficiently reduce peroxynitrite/peroxynitrous acid (ONOO-/ONOOH) to nitrite and protect against oxidation and nitration reactions. Here, we report the second-order rate constant for the reaction of the reduced form of glutathione peroxidase (GPx) with peroxynitrite as (8.0 +/- 0.8) x 10(6) M-1 s-1 (per GPx tetramer) at pH 7.4 and 25 degreesC. The rate constant for oxidized GPx is about 10 times lower, (0.7 +/- 0.2) x 10(6) M-1 s-1. On a selenium basis, the rate constant for reduced GPx is similar to that obtained previously for ebselen. The data support the conclusion that GPx can exhibit a biological function by acting as a peroxynitrite reductase.
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