Research Information System
JOURNAL OF BIOSCIENCES, vol.19, no.1, pp.9-17, 1994 (SCI-Expanded)
Previous studies indicate that ascorbic acid, when combined with copper or iron cleaves several viral DNAs. In this study, we generated the ascorbate radical anion electrochemically in a simple chemical environment without the participation of a metal ion. This solution possesses viral DNA scission activity. The absence of catalytic metal ions [Fe (III) and Cu(II)] in the incubation medium was evidenced by metal chelating agents such as desferrioxamine and EDTA. The radical quenching at high EDTA concentration was attributed to ionic strength of EDTA rather than metal chelation. The effects of antioxidants, radical scavangers, catalase, superoxide dismutase and some proteins on DNA cleavage have been tested. Cleavage may not arise directly from ascorbate free radical but the reaction of the radical form of ascorbate with oxygen may produce the actual reactive species. Aerobic oxidation of ascorbate itself strictly requires transition metal catalysts, however electrochemically produced ascorbyl radical avoided the kinetic barrier that prevented direct oxidation of ascorbic acid with oxygen and eliminated the need for the transition metal ion catalysts.