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A direct electron spin resonance and spin-trapping investigation of peroxyl free radical formation by hematin/hydroperoxide systems. J Biol Chem 1983 Mar 25;258(6):3855-8

Date

03/25/1983

Pubmed ID

6300059

Scopus ID

2-s2.0-0020524329 (requires institutional sign-in at Scopus site)   123 Citations

Abstract

Direct electron spin resonance was used to detect tert-alkylperoxyl radicals generated by hematin and the corresponding hydroperoxides at near-physiological pH values. The spin-trapping method was necessary to detect the less persistent primary ethylperoxyl radical. Under a nitrogen atmosphere, the electron spin resonance signal of the tert-alkylperoxyl radicals decreased, and the ethylperoxyl spin-adduct concentration did not change. Concomitant studies, using a Clark oxygen electrode, show that oxygen was consumed by the hematin-tert-alkyl hydroperoxide systems, but was released by the hematin-ethyl hydroperoxide reaction. Thus, molecular oxygen seems to play a subsidiary role in the hematin-catalyzed decomposition of hydroperoxides. Based on the electron spin resonance and oxygen electrode results, a mechanism for the continuous production of the peroxyl free radicals is proposed for hematin/hydroperoxide systems. The present spectroscopic methodology can be used to search for peroxyl free radical formation by hemoprotein/hydroperoxide systems.

Author List

Kalyanaraman B, Mottley C, Mason RP

Author

Balaraman Kalyanaraman PhD Professor in the Biophysics department at Medical College of Wisconsin




MESH terms used to index this publication - Major topics in bold

Animals
Cattle
Electron Spin Resonance Spectroscopy
Free Radicals
Heme
Hemin
Hydrogen Peroxide
Kinetics
Oxygen Consumption