Role of thiols in radioprotection: radiation chemical aspects.
Using the technique of pulse radiolysis, it has been demonstrated that thiyl radicals (RS.) derived from glutathione (GSH), cysteine (CYSH), penicillamine (PnSH) and 2-mercaptoethanol (ME) interact with oxygen at a high rate. The resulting transient absorption, with a maximum around 540-560 nm, is characteristic of the sulphur peroxyl radical (RSOO.). The yield and the kinetic of formation of RSOO. further support our previous suggestion that thiyl/O2 reaction is an equilibrium. The redox properties of RSOO. are discussed on the basis of the interaction with reductants. Studies on the radio-induced enzyme inactivation in the presence of thiols seem to suggest a damaging role for RSOO. radicals.
Tamba
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Istituto F.R.A.E. del C.N.R., Bologna, Italy.
D003545:Cysteine / Q000494:pharmacology; D004249:DNA Damage; D004307:Dose-Response Relationship, Radiation; D005609:Free Radicals; D005978:Glutathione / Q000494:pharmacology; D007700:Kinetics; D009113:Muramidase / Q000378:metabolism / Q000528:radiation effects*; D010396:Penicillamine / Q000494:pharmacology; D011837:Radiation-Protective Agents; D013438:Sulfhydryl Compounds / Q000494:pharmacology; D013439:Sulfhydryl Reagents / Q000494:pharmacology
D005609:Free Radicals; D011837:Radiation-Protective Agents; D013438:Sulfhydryl Compounds; D013439:Sulfhydryl Reagents; D009113:Muramidase; D005978:Glutathione; D010396:Penicillamine; D003545:Cysteine