The action of papain on wool keratin

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Abstract
The products formed when wool is hydrolyzed by papain and Na H203 were examined. Acidification of the digest to pH 4 precipitates a complex polypeptide material, the cystine content of which is lower than that of the cortical cells which are liberated during the enzyme digestion. The material remaining in soln. consists largely of polypeptides, although small amts. of free glycine are produced. Papain fractionated in a number of different ways to remove natural "activators" still digests wool readily in the presence of bisulfite. Wool which has been treated with alkali to convert some of the disulfide linkages to lanthionine linkages is attacked by papain and bisulfite at an increased rate. The amino end groups of the peptides produced in the reaction were estimated by Sanger''s technic. Those of the soluble peptides consist of leucine-isoleucine, valine, alanine, glycine, threonine, serine, glutamic acid and aspartic acid.