ABSTRACT
The most common techniques used in the preparation and isolation of metallothionein are gel filtration, ion-exchange chromatography, and isoelectric focusing. Separation techniques based on the charge properties of metallothionein, such as ion-exchange chromatography and isoelectric focusing, have shown that different forms of metallothionein often exist in the same organ, human and horse kidney, rabbit liver, human liver, and rat liver. Metallothionein was discovered because of its capacity to bind cadmium and for the possibility to exchange cadmium for other metals, such as mercury, copper, and zinc in vitro. The amino acid sequence has been determined for metallothionein obtained from various mammals such as mice, rats, rabbits, horses, and also from humans. Parenteral administration of cadmium or zinc is the most effective means of inducing metallothionein synthesis. A high content of zinc- and copper-containing metallothionein in newborn makes it possible to assume that metallothionein serves as a storage protein for these metals in early life.
