The Interaction of Copper(II) Complexes \({\text{Cu(Gly)}}_{2}^{0}\), Cu(Bipy)Gly+, and \({\text{Cu(Bipy)}}_{2}^{{2 + }}\) with Glutathione

Abstract

The interaction of three copper(II) complexes \({\text{Cu(Gly)}}_{2}^{0}\), \({\text{Cu(Bipy)}}_{{\text{2}}}^{{{\text{2 + }}}}\), and Cu(Bipy)Gly⁺ with glutathione in aqueous solution (pH 7.4, 0.2 M NaCl, 25°C, c_Cu = (1–10) × 10^–4 M, c_GSH = 1.0 × 10^–3 M) was studied. These and similar complexes are commonly used in biological experiments to evaluate anticancer and antimicrobial activity. Under physiological conditions, copper(II) complexes undergo an almost irreversible transformation into more stable thiolate copper(I) complexes, accompanied by complete loss of the identity of the original complexes. In all cases, the redox interaction of copper(II) complexes with glutathione proceeded rapidly and quantitatively. The main products were a bisthiolate copper(I) complex and glutathione disulfide.