The Cd-Chelex assay: A new sensitive method to determine metallothionein containing zinc and cadmium
- 88 Downloads
A rapid and sensitive one-vial procedure to determine metallothionein (MT) containing zinc (Zn) and cadmium (Cd) is described. New features of this Cd-saturation method are: high molecular weight Cd-binding proteins are denatured by treatment with acetonitrile (50% final concentration), and excess of Cd is bound to a cation exchange resin (Chelex-100). With this method, MT has been measured, e.g. in liver of control and zinc- or cadmium-treated rats, in human liver and in cultured human fibroblasts down to absolute amounts of 0.1 μg. The Cd-Chelex assay is 10 times more sensitive than the established Cd-heme assay (Dieter et al. 1986) and therefore is particularly suitable to quantify MT in small tissue samples (e.g., liver biopsies of a few milligrams) and in extrahepatic tissues or cell cultures with low MT concentrations.
Key wordsChelex Metallothionein Cd-saturation assay Zinc Cadmium
Unable to display preview. Download preview PDF.
- Cai W, Stillman MJ (1988) Metal binding in metallothioneins: competition for cadmium and zinc between Chelex-100 and metal binding sites in metallothionein. Inorg Chim Acta 152: 111–115Google Scholar
- Foulkes EC (ed) (1982) Biological roles of metallothionein. Elsevier/North Holland, New YorkGoogle Scholar
- Kägi JHR, Kojima Y (eds) (1987) Metallothionein II. Birkhäuser Verlag, BaselGoogle Scholar
- Nolan CV, Shaikh ZA (1987) Induction of metallothionein in rat tissues following subchronic exposure to mercury shown by radioimmunoassay. Biol Trace Element Res 12: 419–428Google Scholar