Metallothionein as a trap for reactive organic intermediates.

Abstract

Metallothionein is a cadmium-binding protein first isolated from equine renal cortex by Margoshes and Vallee (1957). It is a protein of low molecular weight (about 6,000) having a very high cysteine content (about 30% of the amino acid residues) and an absence of aromatic amino acids and histidine (Kagi et al., 1974). Similar proteins have been isolated from the liver and/or kidney of humans (Pulido et al., 1966; Buhler and Kagi, 1974), and many other species. The amino acid sequences of equine renal metallothionein (Kojima et al., 1976) and hepatic metallothionein from mice (Huange et al., 1977) have been determined. The metallothionein from these two sources both contain 20 cysteine residues (out of a total of 61 amino acid residues) and remarkable structural homology in the amino acid sequence.