The Enzymatic Digestion of Wool*

It has generally been accepted that keratins are not attacked by enzymes. In a review of the literature by Barritt (1) the property of non-digestibility was an essential part of the definition of a keratin. However, there has been evidence for the digestion of wool by pancreatin. Wool that had been suspended in solutions of varying pH (2 to 10) for 48 hours at room temperature was slowly attacked by the enzymes (2). Wool previously treated at pH 10 was most readily digested. If the alkali was stronger (pH 11) and the temperature was raised to 37”, the same period of treatment produced a keratin that was extensively attacked by pancreatin over long periods of time (200 to 400 hours) (3). Keratins have been found to be digested by the crop juice of predatory birds (4) and by the intestinal juice of the larvss of a species of clothes-moth (5). Several investigators have observed enzymatic digestion of protein derivatives prepared by the action of oxidizing and reducing agents on wool and hair (5-8). The present investigation is concerned with the enzymatic hydrolysis of wool keratin and of its derivatives produced by the action of the reducing agent, thioglycolic acid. For comparison, a well characterized protein, casein, was studied under similar conditions.