EFFECT OF DIGLYCYLHISTIDINE ON THE OXIDATION OF ASCORBATE CATALYZED BY CU(II)

Glycylglycylhisttdine (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.), O_2~r, H_2O_2 and·OH during the oxidation.