Reaction mechanisms of peroxyl and C-centered radicals with sulfhydryls.
Rate constants for reactions of a peroxyl (CCl3OO.) and C-centered radicals, that is, phenyl (.C6H4CH2COO-) and vinyl (uracil-5-yl), with an aromatic thiol (p-CH3OC6H4SH) were measured over a pH range (3-12) to include ArSH and ArS- forms. The pH dependence of these rate constants indicates that peroxyl radicals react by a redox mechanism while the C-centered radicals react by an H-atom transfer process. The different mechanisms encountered in the repair of various radicals suggest design features to be incorporated into antiagents, such as radioprotectors and anticarcinogens.
D005609:Free Radicals; D006863:Hydrogen-Ion Concentration; D013438:Sulfhydryl Compounds
D005609:Free Radicals; D013438:Sulfhydryl Compounds