Chemical interactions of mercury species and some transition and noble metals towards metallothionein (Zn7MT-2) evaluated using SEC/ICP-MS, RP-HPLC/ESI-MS and MALDI-TOF-MS.

The chemical affinities of three submetallomes ("Mn, Co, Ni, Cu, Cd"; "Pd, Pt, Au"; and "Hg, CH3Hg, C2H5Hg-THI") towards metallothionein-2 (Zn7MT-2) in a physiological solution environment were evaluated using SEC/ICP-MS together with RP-HPLC/ESI-IT-MS and MALDI-TOF-MS, and followed the order: "Zn(2+) < Cu(2+), Cd(2+) > Ni(2+) > Mn(2+), Co(2+)"; "Pd(2+) > Au(3+) > Pt(2+)"; and "Hg(2+) > CH3Hg(+) > C2H5Hg-THI". Besides these, the structural change and composition of the CH3Hg-MT-2 complexes formed during the CH3Hg(+) titration process were further investigated using CD spectroscopy, RP-HPLC/ESI-MS and MALDI-TOF-MS, indicating that linear and more hydrophobic (CH3Hg)xMT-2 (x = 12, 13, 14, 15, 16, 17, 18, 19 and 20) were formed. This information is important in understanding the interactions of the metals with Zn7MT-2 and their corresponding biological functions and toxicities.