Interaction of dimethylsulfoxide and diethylsulfoxide complexes of platinum(II) with bovine serum albumin

We have used electronic absorption spectroscopy in the UV region to study the interaction of a dimethylsulfoxide complex of platinum(II) (cis-Pt(DMSO)₂Cl₂]) and a diethylsulfoxide complex of platinum (II) (cis-Pt(DESO)₂Cl₂]) with bovine serum albumin (BSA). We have calculated the physicochemical binding parameters for binding with BSA (the binding constants and the Hill coefficient). We found that sulfoxide ligands promote an increase in the rate of binding of the complexes with BSA. Binding of cis-Pt(DMSO)₂Cl₂] and cis-Pt(DESO)₂Cl₂] with BSA leads to a decrease in the thermal stability of the protein. The leaving groups in the complexes for binding with BSA are the sulfoxide molecules, and the mechanism for binding between the dialkylsulfoxide complexes and the protein remains unchanged.