The N-terminal residues of Merino 64's quality wool and of a purified protein derivative extracted from it, S-carboxymethyl kerateine 2, have been determined. A similar total N-terminal residue content is present in both wool and S�carboxymethyl kerateine 2 comprising glycine, serine, threoni~e, aspartic acid, glutamic acid, and alanine. These occur in different proportions in the two materials and valine is an additional N-terminal amino acid present only in wool.