High-sulphur proteins from alpha-keratins. I. Heterogeneity of the proteins from mouse hair.

The heterogeneity of the reduced and S-carboxymethylated high-sulphur protein fraction from mouse hair has been examined by chromatography and polyacrylamide gel electrophoresis at pH values above and below the isoelectric region. Considerable heterogeneity is observed both in size (molecular weight range 12000-45000) and in charge. Amino acid analysis of a number of column chromatographic fractions shows the high-sulphur proteins to be largely composed of proteins with a carboxymethylcysteine content above 25 residues and a pronounced heterogeneity in arginine content. Their chromatographic behaviour is similar to that observed for the ultra-high-sulphur proteins from wool.