Reaction of No With O2. Implications for the Action of Endothelium-Derived Relaxing Factor (EDRF)

Abstract
Under physiological pH conditions (pH 7.2-7.4) the rate constant of the reaction NO + O2 yielding peroxonitrite (ONOO) was determined as k = (3.7 ± 1.1) × 107 M 1 s 1. The decay of peroxonitrite at this pH follows first order kinetics with a rate constant of 1.4 s 1. At alkaline pH peroxonitrite is practically stable. Possible consequences of these reactions for the biological lifetime of EDRF will be discussed.