Spectroelectrochemical Study of the Hemin - Glutathione Interaction in the Absence and Presence of Surfactants

摘要

The interaction of hemin with reduced glutathione (GSH) was studied using cyclic and linear sweep voltammetry with stationary and rotating disc electrodes and UV-VIS spectroelectrochemical experiments. A 1∶1 global stoichiometry and similar values for the hemin -^sGSH binding constant were obtained in aqueous media in the presence of sodium dodecyl sulfate (SDS) with those in dimethylsulphoxide (DMSO). A comparison between the family of curves obtained during the electrochemical reduction of hemin with that recorded at the hemin -^sGSH interaction points to different absorption bands, leading to the idea of a complexation of the Fe{sup}(III) by GSH, rather than a Fe{sup}(III)→Fe{sup}(II) reduction. The biochemical relevance of the hemin-glutathione interaction is related to the presence of GSH in normal erythrocytes in high concentrations (1-4mM), being involved as an agent in the "trapping" of free hemin from the cell cytosol.