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
03/25/1983Pubmed ID
6300059Scopus ID
2-s2.0-0020524329 (requires institutional sign-in at Scopus site) 123 CitationsAbstract
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 RPAuthor
Balaraman Kalyanaraman PhD Professor in the Biophysics department at Medical College of WisconsinMESH terms used to index this publication - Major topics in bold
AnimalsCattle
Electron Spin Resonance Spectroscopy
Free Radicals
Heme
Hemin
Hydrogen Peroxide
Kinetics
Oxygen Consumption