Reversible dissolution of glutathione-mediated HgSe(x)S(1-x) nanoparticles and possible significance in Hg-Se antagonism.

A new pathway is proposed for the in vivo biomineralization of HgSe(x)S(1-x)(s) (0 < x < or = 1), which is thought to be the ultimate metabolic product responsible for the Hg-Se antagonism in biological systems. The pathway involves the reaction of inorganic Hg(II) with selenite in the presence of glutathione (GSH). The resulting GSH-mediated HgSe(x)S(1-x) nanoclusters are reversibly soluble depending on the pH, which might have played a role in the distribution pattern of HgSe(x)S(1-x)(s) in different tissues. The HgSe species involved and the nature of bonding were studied by UV-visible spectroscopy, infrared spectroscopy, microprobe scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy.