Cadmium-binding properties of glutathione: A chemometrical analysis of voltammetric data

The complexation of glutathione (GSH) by Cd2+ has been investigated as a model for the coordination chemistry of Cd2+ fly thiol-containing peptides. Experimental data obtained by differential pulse polarography (DPP) for different Cd2+-to-GSH concentration ratios at fixed pH have been globally analyzed by the recently proposed multivariate curve resolution (MCR) method. Polarograms from experiments a fixed Cd2+-to-GSH concentration ratios but changing pH values have been univariately deconvoluted at each pH value. In both cases, the obtained single DPP peaks can be associated to specific electrode processes. The results obtained in this work, together with structural data From the literature, allow us to propose a model for the complexation of Cd2+ by GSH involving the formation of Cd(GSH), and Cd-2(GSH)(2) complexes. Moreover a scheme for the electrode process is also proposed. (C) 1997 Elsevier Science Inc.