Interaction between Copper(II)-Arginine Complexes and HO2/O2- Radicals, a Pulse Radiolysis Study

Article abstract of DOI:10.1021/ja00246a024

Superoxide radicals were shown to react with all four Cu(II)-arginine complexes that exist between pH 1.5 and 12.5; k₁₀(O2^- + CuArgH²⁺)= 3.3E9 M^-1 s^-1, k₁₂(O2^- + Cu(ArgH)2²⁺)= 1.3E7 M^-1 s^-1, k₁₃(O2^- + CuArg2H⁺)= 1E6 M^-1 s^-1, k₁₄(O2^-+ CuArg⁺)= 1E8 M^-1 s^-1.The system was studied in detail at pH 2.0 and pH >/= 7.At low pH the mechanism was shown to proceed via a CuO2H²⁺ complex while at higher pH a superoxide complex of the Cu(II)-arginine complexes was formed.The results are discussed in terms of the currently accepted mechanism by which SOD-Cu²⁺ dismutates O2^- radicals.