[Structure and function of metallothionein].
Metallothionein is defined as a low molecular weight protein of high cysteine and heavy metal contents. Although metallothionein does not show any enzymic activities, multifunctional roles in the body have been proposed such as a chelator to harmful heavy metals and excessive essential metals, a scavenger to various radicals and active oxygen species, and a regulator in the cell proliferation process. These biological roles are manifested through the mercaptide bond (metal-sulfurbond) that characterize metallothionein. All metals bound to metallothionein are coordinated tetrahedrally by cysteinyl sulfurs and this coordination structure forms two clusters consisting of 11 cysteinyl residues and 4 cadmium and/or zinc (cluster alpha), and 9 cysteinyl residues and 3 metals (cluster beta). Metallothionein can be induced by metals, organic chemicals and various kinds of stress and non-chemical stimulation. The gene structure and the regulation mechanisms for its expression are well understood and the regulator region is widely used to control fused structure genes. The biological roles of metallothionein are now studied using transgenic and MT-gene knock out mice.
Suzuki
K T
KT
Faculty of Pharmaceutical Sciences, Chiba University.
D000818:Animals; D002614:Chelating Agents; D016166:Free Radical Scavengers; D006801:Humans; D008668:Metallothionein / Q000737:chemistry* / Q000502:physiology*; D051379:Mice; D018345:Mice, Knockout
D002614:Chelating Agents; D016166:Free Radical Scavengers; D008668:Metallothionein