THE KINETICS OF ASCORBIC ACID OXIDATION CATALYZED BY Cu(Ⅱ)/H₂DCA IN THE PRESENCE OF DNA

In phosphate buffer (pH 7. 40), at 20. 00 ±0. 05 ℃, the visiblespectra of Cu (Ⅱ) and Cu (Ⅱ) complexes and the kinetics of ascorbic acid oxidationcatalyzed by Cu (Ⅱ)/H₂DCA in the presence of DNA were studied. Measurements were re-ported on rate of ·OH formation by the oxidation of ascorbic acid in the presence ofCu (Ⅱ)/H₂DCA. It showed that ternary complex Cu(Ⅱ)/₂DCA/DNA may exist in thesystem in which DNA strand was broken by ascorbic acid in the presence of Cu (Ⅱ) /H₂DCA, and it was assumed that the DNA- breaking action of ascorbic acid in the pre-sence of Cu (Ⅱ)/H₂DCA conformed to site-specific Fenton reaction mechanism. All the re-suit of DNA-breaking action can be explained in terms of this site-specific Fentonreaction, mechanism.