On the radiation chemistry of thymine in aqueous solution.
The reactions of thymine in aqueous solution with radiation-induced radicals OH, H, and e-aq were studied under various conditions. Competition studies using scavengers of OH radicals (methanol, ethanol, iodide) or of e-aq and/or H atoms (N2O, H+, O2) led to the conclusion that OH and H radicals destroy the chromophoric group of thymine, but e-aq does not. A trace of O2 proved to be necessary to obtain maximal destruction. Removal of the last traces of O2 resulted in a decrease of the destruction yield, possibly through restitution reactions. It was found that (1) alcohol radicals destroy thymine, even in the presence of O2; (2) the rate constant, k(OH + thymine) = 4.3 X 10(9) M(-1) sec(-1) (from competition with iodide); and (3) k(H + thymine) = 8 X 10(8) M(-1) sec(-1) (from competition with O2 in acid solution).
Loman
H
H
Natuurkundig Laboratorium der Vrije Universiteit, De Boelelaan 1081, Amsterdam, The Netherlands.
Blok
J
J
D003198:Computer Simulation; D004307:Dose-Response Relationship, Radiation; D006859:Hydrogen / Q000737:chemistry / Q000528:radiation effects; D017665:Hydroxyl Radical / Q000737:chemistry / Q000528:radiation effects; D007700:Kinetics; D008956:Models, Chemical; D010100:Oxygen / Q000737:chemistry / Q000528:radiation effects; D011829:Radiation Dosage; D012996:Solutions; D012997:Solvents / Q000737:chemistry* / Q000528:radiation effects*; D013941:Thymine / Q000737:chemistry* / Q000528:radiation effects*; D014867:Water / Q000737:chemistry*
D012996:Solutions; D012997:Solvents; D014867:Water; D017665:Hydroxyl Radical; D006859:Hydrogen; D013941:Thymine; D010100:Oxygen