Nature of the Reaction of Wool with Alkali

The course of the reaction of the cystine in wool with alkali has been reinvestigated. The earlier findings that one sulfur atom is split from each molecule of cystine are confirmed. Of the residual noncystine sulfur in the alka li-tregted wool, mbre than 25 percent has been accounted for as lanthionine. No signifi cant amounts of sulfhydryl groups are in the t reated wools. The results lead to the conclusion that the alkali cleavage of the disulfide group does not consist prima rily in a hydrolytic rupture between the s ulfur atoms with the formation of a sulfhydryl compound and a sulfenic acid, as postulated earlier; rather, they are more consistent with a mechanism recently advanced by N icolet and Shinn, which involves a rupture between s ulfur and carbon to yield dehydroalanine and a -CH 2 -S-SH residue. An atom of sulfur is then eliminated from the latter and the sulfhydryl group thus formed reacts with dehyclroalanine to form lantilionine.