Hydroxyl Radical Generation in the Nadh/Microsomal Reduction of vanadate

Abstract

ESR spin trapping measurements demonstrate generation of hydroxyl (.OH) radical from reduction of vanadate by rat liver microsomes/NADH without exogenous H₂O₂. Catalase decreases the OH signal while increasing a vanadium(4+) signal. Addition of superoxide dismutase (SOD) or measurements under an argon atmosphere show decreased .OH radical production. The results suggest that during the one-electron vanadate reduction process by microsomes/NADH, molecular oxygen is reduced to H₂O₂, which then reacts with vanadium (4+) to generate .OH radical via a Fenton-like mechanism.

Key Words:

• OH radical
• vanadate reduction
• O₂-reduction
• Fenton-like mechanism