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Dosimetry determines the initial OH radical concentration in fast photochemical oxidation of proteins (FPOP).

ABSTRACT: Fast photochemical oxidation of proteins (FPOP) employs laser photolysis of hydrogen peroxide to give OH radicals that label amino acid side-chains of proteins on the microsecond time scale. A method for quantitation of hydroxyl radicals after laser photolysis is of importance to FPOP because it establishes a means to adjust the yield of •OH, offers the opportunity of tunable modifications, and provides a basis for kinetic measurements. The initial concentration of OH radicals has yet to be measured experimentally. We report here an approach using isotope dilution gas chromatography/mass spectrometry (GC/MS) to determine quantitatively the initial •OH concentration (we found ~0.95 mM from 15 mM H2O2) from laser photolysis and to investigate the quenching efficiencies for various •OH scavengers.

SUBMITTER: Niu B

PROVIDER: S-EPMC5613943 | biostudies-literature | 2015 May

REPOSITORIES: biostudies-literature

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Dosimetry determines the initial OH radical concentration in fast photochemical oxidation of proteins (FPOP).

Niu Ben B Zhang Hao H Giblin Daryl D Rempel Don L DL Gross Michael L ML

Journal of the American Society for Mass Spectrometry 20150225 5

Fast photochemical oxidation of proteins (FPOP) employs laser photolysis of hydrogen peroxide to give OH radicals that label amino acid side-chains of proteins on the microsecond time scale. A method for quantitation of hydroxyl radicals after laser photolysis is of importance to FPOP because it establishes a means to adjust the yield of •OH, offers the opportunity of tunable modifications, and provides a basis for kinetic measurements. The initial concentration of OH radicals has yet to be meas ...[more]

PMID: 25712620

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