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.

Key Words:

• Superoxide anion
• nitric oxide
• peroxonitrite
• endothelial derived relaxation factor
• biological messenging.