Oxidation of zinc finger cysteines to thiosulfinate

Experiments were conducted to determine thiosulfinate formation in a protein or peptide. The oxidation of two cysteines in Spl-3 to thiosulfinate was analyzed. Quantitative HPLC analysis on the peptide products rom 24-hour reactions of Spl-3 super 22 with oxygen or hydrogen peroxide in the absence or presence of Zn(II) or Ni(II) was performed. The findings indicated the permanent elimination of thiosulfinate's ability to bind to zinc and interact with DNA.