Further Studies on the Digestion of Wool Keratin by Papain-Urea: the Effect of Adding Compounds that Rupture Disulphide Bonds in Alkaline Solution

Abstract

Whereas the optimum pH for digestion of wool by papain-bisulphite-urea is 7.0, a higher pH value is required for optimum digestion when bisulphite is replaced by sodium thioglycollate, cysteine hydrochloride, or potassium cyanide. Thioglycollate at pH 9.5 is superior to cysteine at the same pH or to bisulphite at pH 7.0 in promoting wool digestion by papain solutions containing urea. Cyanide is least effective. When wool is incubated in solutions of bisulphite, thioglycollate, cysteine, or cyanide in the absence of papain and urea, the extent of splitting of disulphide bonds runs parallel with the enzyme digestion observed in the presence of these reagents.