The Reaction of no With Superoxide

Abstract

The rate constant for the reaction of NO with ·O₂⁻ was determined to be (6.7 ± 0.9) × 10⁹ 1 mol⁻¹ s⁻¹, considerably higher than previously reported. Rate measurements were made from pH 5.6 to 12.5 both by monitoring the loss of ·O₂⁻ and the formation of the product ⁻OONO. The decay rate of ⁻OONO, in the presence of 0.1 moll⁻¹ formate, ranges from 1.2s⁻¹ at pH 5 to about 0.2s⁻¹ in strong base, the latter value probably reflecting catalysis by formate.

Key Words:

• Endothelium-derived relaxing factor
• nitric oxide
• peroxynitrite
• superoxide anion.