Free radical induced redox reactions of 2,4,6-triaminopyrimidine: A pulse radiolysis study

Kinetics and mechanism of reactions of 2,4,6-triaminopyrimidine (TAP) with some free radicals have been studied using pulse radiolysis technique. TAP has been found to react with hydrated electron (3.1 x 10(8) M-1 s(-1)), hydroxyl radical (4.0 x 10(9) M-1 s(-1)), trichloromethyl peroxyl radical (1.1 x 10(8) M-1 s(-1)), and sulfate radical (4.5 x 10(9) M-1 s(-1)). Density functional calculations have been performed to assign absorption maxima of transients produced on oxidation of TAP as: TAP(center dot+) radical cation (similar to 430, similar to 600, similar to 720 nm), TAP(C5)(center dot) radical (similar to 300, similar to 320 nm), aminyl TAP(NH)(center dot) radical (similar to 300, similar to 340, similar to 440 and similar to 520 nm) and TAP-OH center dot radical adduct (640 nm). Almost 72% of TAP transients produced with hydroxyl radical have been found to be oxidizing in nature, which react with tyrosine (8.0 x 10(7) M-1 s(-1)), glutathione (1.2 x 10(8) M-1 s(-1)) and bovine serum albumin protein (7.8 x 10(8) M-1 s(-1)).