Disulphide Bond Breakdown in Wool during High–temperature Steam Treatments

The extent to which cystine residues react when wool is steamed at temperatures above 10077deg;C was found to be very dependent on the pH of the wool and the temperature of the treatment, but was less sensitive to variations in the time of treatment. Extending the wool by up to 20% had no significant effect on cystine reactivity. Lanthionine was detected in the steamed wool in amounts which corresponded, approximately mole for mole, with the cystine losses recorded for the same samples, thus indicating that, under these conditions, even when the wool is at pH 3 0, almost all the cystine undergoing modification is converted to lanthionine. Measurements of the urea–bisulphite solubility of steamed wool provided indirect evidence of lanthionine formation. A new method of estimating lanthionine in protein hydrolysates, based on one–dimensional thin–layer chromatography combined with measurements of spot areas, is described.