Vitamin C Causes a Much-Pronounced Damange to DNA in Presence of Cd2+ but not in Presence on Zn2+ or Ag+. Why?

Abstract

Super oxide dismutase and rhodamine assays carried out in the present study show that free radicals were produced from the interaction between molecular oxygen and 1: 1 mixture of cadmium(II) acetate and ascorbate or 1 : 1 mixture of silver(I) acetate and ascorbate. Molecular modelling analysis combined with pH measurement shows that in presence of Cd²⁺, ascorbic acid essentially acts as a strong polyprotic acid whereas in presence of Ag⁺, it acts as a monoprotic acid. It is believed that the binding of ascorbate with the metal ions Cd²⁺ and Ag⁺ causes the molecular activation, which is more susceptible to attack, by molecular oxygen. Reactive oxygen species produced from the interaction between activated\ ascorbate species and molecular oxygen damage DNA.