[Effect of diglycylhistidine on the oxidation of ascorbate catalyzed by Cu(II)]

Glycylglycylhistidine (GGH) was synthesized using mixed anhydride method, and Cu(II): GGH = 1:1 complex was identified using UV, ESR, CD, ORD and FAB/MS technique. The oxidation of ascorbate catalyzed by cupric ion in RPMI 1640 medium (pH 7.40) was studied. The activation energy E = 39.2 kJ/mol. The addition of GGH inhibited the oxidation of ascorbate catalyzed by cupric ion. The investigations with ESR and fluorimetry indicate that there are Cu(I), ascorbate radical (AH), O2-., H2O2 and .OH during the oxidation.