Metal binding in metallothioneins: Competition for cadmium and zinc between chelex-100 and metal binding sites in metallothionein |
| |
Institution: | 1. Division of Hemostasis and Thrombosis, Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA;2. George Washington University School of Medicine, Washington, District of Columbia, USA;3. Harvard Medical School, Boston, Massachusetts, USA;4. Boston University Medical Center, Boston, Massachusetts, USA;5. Center for the Development of Therapeutics, Broad Institute, Cambridge, Massachusetts, USA;6. Division of Hematology and Blood Transfusion Service, Massachusetts General Hospital, Boston, Massachusetts, USA |
| |
Abstract: | A study of the use of the metal chelation properties of Chelex-100 in metal binding reactions of metallothionein (MT), is described. The stoichiometric ratios of bound metals in MT were determined at several stages during a titration in which the Zn(II) in Zn7MT was displaced by Cd(II), by using Chelex-100 to sequester the free zinc. The stoichiometric ratios provide convincing supporting evidence that the complicated circular dichroism spectral properties observed during the titration arise because the incoming cadmium is distributed across both domains in the protein. It is shown that Chelex-100 does not sequester zinc or cadmium directly from the metallothionein binding sites. Use of Chelex-100 over the temperature range −20 to 65 °C is demonstrated. The chelation capacity of Chelex-100 (in terms of μ metal ion/mg resin) has been determined for a range of elements important in metal toxicology, including: cadmium (33 μ), zinc (22 μ), copper (19 μ), silver (38 μ), lead (40 μ) and mercury (40 μ). |
| |
Keywords: | |
本文献已被 ScienceDirect 等数据库收录! |
|