Ligand substitution and redox reactions of the pro-drug auranofin: Albumin-gold-glutathione is a likely metabolite

A comparative study of the interaction of Myocrisin with albumin and gamma-globulin

The reactions of Myocrisin with albumin and gamma-globulin have been investigated using atomic absorption spectrometry and gel filtration. Albumin rapidly binds gold up to the levels predicted from the concentration of free sulphydryl groups present in the protein. However, in the presence of glutathione, gold incorporation is increased, suggesting that in vivo, free thiols (glutathione, thiomalate) may facilitate gold uptake by the protein. In comparison, gamma-globulin is found to be capable of binding up to one atom of gold per molecule of protein in a slow reaction which requires high Myocrisin concentrations.