27—INTER-MOLECULAR –SS– BONDS IN BOTH (A+B) AND (C+D) CYSTINE FRACTIONS OF WOOL

Abstract

Work which showed that the more reactive, (A+B), fraction of wool cystine contains inter-molecular disulphide cross-links has been extended to show that the less reactive, (C+D), fraction also contains inter-molecular cross-links. Thus, one explanation of the difference in reactivity between the fractions, viz., that the (A+B) cystine residues form inter-molecular cross-links and the (C+D) residues are intra-molecular, is made untenable. The differences in reactivity are, nevertheless, a result of the protein secondary structure, because, if this structure is disorganized by a hydrogen-bond-breaking reagent, then the rate and extent of the reaction of the fractions with alkali are altered.