QUANTITATIVE DETERMINATION OF THE SUPEROXIDE RADICALS IN THE XANTHINE OXIDASE REACTION BY MEASUREMENT OF THE ELECTRON SPIN RESONANCE SIGNAL OF THE SUPEROXIDE RADICAL SPIN ADDUCT OF 5, 5-DIMETHYL-1-PYRROLINE-1-OXIDE

Abstract

Reactivities of biologically active compounds with superoxide radicals were examined by measurement of electron spin resonance (ESR) spectra of 5-hydroperoxy-2, 2-dimethy 1-1-pyrrolidinyloxyl formed from 5, 5-dimethyl-1-pyrroline-1-oxide and the superoxide radicals generated by xanthine-xanthine oxidase system. Quantitative determination of the superoxide rachcals was performed by comparing the intensity of the spin adducts with chat of 4-hydroxy-2, 2, 6, 6-tetramethyl-pipperi-dinooxyl whose spin concentration was determined. Methyl viologen enhanced the formation of this spin adducts, while, rutin and luteoskyrin prevented it.