Mouse liver metallothioneins. Complete amino acid sequence of metallothionein-I.

The amino acid sequence of thionein-I, a major mouse liver thionein, is presented. Thionein-I is a single chain polypeptide which consists of 61 amino acid residues and has the amino acid composition Cys20, Asp3, Asn1, Thr5, Ser9, Gln1, Pro2, Gly5, Ala5, Val2, Met1, Lys7, with N-acetylmethionine and alanine as NH2- and COOH-terminal amino acids, respectively. Automated sequence analysis of a major cyanogen bromide peptide consisting of 60 amino acid residues, as well as characterization of the peptides obtained from trypsin and papain digestion, led to the elucidation of the complete primary structure of this protein. Remarkable structural homology is observed between the mouse thionein-I and the equine renal thionein-1B (Kojima, Y., Berger, C., Vallee, B.L., and Kägi, J.H.R. (1976) Proc. Natl. Acad. Sci. U.S.A. 73, 3413-3417).