12—THE FORMATION OF LYSINOALANINE AND LANTHIONLNE IN WOOL FIBRES STRETCHED IN BOILING WATER, AND THEIR RELATION TO PERMANENT SET

Abstract

When wool fibres are held at 40% extension in boiling water for increasing periods of time, there is a progressive decrease in their cystine contents with concomitant increases in their lanthionine and lysinoalanine contents. After 3 hr, the contents of these amino acids have reached a maximum, which coincides with the maximum retention of set. At this time, approximately 24% of the cystine residues have been modified. The mechanism of set is a complex phenomenon involving conformational changes in the proteins constituting the microfibril–matrix structure of the wool fibre. Whereas the results in this paper support the cross-linkage-stabilization theory of set postulated by Speakman, their implications, both for this and for the thiol–disulphide-interchange theory of set, are discussed in the light of modern ideas on the structure of wool.