Nature of the resistance of wool to digestion by enzymes

Abstract

Wool that has neither been injured mechanically nor modified chemically is completely resistant t o attack by the proteolytic enzymes-pepsin, trypsin, chymotrypsin , and papain. When the cuticle or scale layer of the fib ers is damaged by mecha nical means, the wool becomes susceptible to attack by p epsin and chymotryp sin. Under these conditions only a small portion of the wool is digested, yet the fi bers are considerably weakened and their fibrous structure is partly destroyed. Wool in which the disulfide cross-linkages have been broken, as by r eduction, or by reduction followed by methylation, is almost completely digested by p epsin and chymotrypsin, but is attacked only slightly by trypsin . When the reduced wool is reoxidized and its sulfhydryl groups are converted t o disulfide groups, the wool regains its original sta bility. When the sulfhydryl groups of the reduced wool are converted to bis-thioether groups by the action of an aliphatic dihalide, the stability of the wool toward enzymes is greatly enhanced. CONTENTS Page I. Introduction _______________________ _________ ________________ ___ _ 459 II. Experimental procedure _________________________ _________________ 461 1. Materials _____ ______ _____________________________________ 461 2. M ethods _________________________________________________ 461 (a) Detection of attack by enzymes _____ _______________ _ 461 (b) Chemical treatments ____ ___________ ________ _____ __ 462 (c) Mechanical treatments ____ ________ __________ ____ __ 462 (d) Enzyme treatments ___________ ____ _______ _____ ___ _ 462