Electron spin resonance of spin trapped radicals in γ-irritated polycrystalline dipeptides. Chromatographic separation of radicals

Article abstract of DOI:10.1139/v82-214

Polycrystalline dipeptides (glycyl-glycine, glycyl-L-valine, glycyl-L-leucine, L-alanyl-glycine, and L-prolyl-L-alanine) were γ-irradiated at room temperature in the absence of air.Subsequently they were dissolved in aqueous solutions containing 2-methyl-2-nitrosopropane as the spin trap.From the esr spectra of the nitroxide radicals separated by high-performance liquid chromatography, structural assignments of the radicals were made.For glycyl peptides, H-abstraction from the α-carbon atoms of the carboxyl terminal residues and from the side-chains were observed.For L-alanyl-glycine , H-abstraction from the glycyl residue and the formation of the deamination radical could be shown to occur.For L-prolyl-L-alanine, the ring opening (deamination) reaction, decarboxylation and H-abstraction from the C-terminal α-carbon were seen.