ESR and spin-trapping study of free radicals in gamma-irradiated solid lysozyme.
Free radicals produced by gamma-irradiation of solid lysozyme were investigated by a technique combining ESR, spin-trapping and enzymatic digestion. MNP and DMPO were used as spin-trapping reagents. The solid lysozyme was first gamma-irradiated and then dissolved in an aqueous solution containing the spin-trapping reagent to stabilize free radicals. The spin adducts of lysozyme were digested to oligopeptides to get ESR spectra having a well-resolved hyperfine structure. The ESR spectra obtained showed that carbon-centered radicals, -CH-, at the side chains of amino acids, and thiyl radicals, -CH2-S., at disulfide bridges were produced in gamma-irradiated solid lysozyme.
Inanami
O
O
Department of Radiation Biology, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Japan.
Kuwabara
M
M
Sato
F
F
D004578:Electron Spin Resonance Spectroscopy / Q000379:methods; D005609:Free Radicals; D005720:Gamma Rays; D009113:Muramidase / Q000378:metabolism / Q000528:radiation effects*; D009603:Nitroso Compounds; D013113:Spin Labels
D005609:Free Radicals; D009603:Nitroso Compounds; D013113:Spin Labels; D009113:Muramidase; C034526:tert-nitrosobutane