The distribution of readily reducible disulphide bonds in wool

Abstract
Wool was reduced between 6 and 60% at pH 5.0 with mercaptoacetate, alkylated with [2-C14]iodoacetate and fractionally extracted with alkaline mercaptoacetate. After alkylation with unlabelled iodoacetate these fractions were separated by acid precipitation into proteins of high- and low-sulphur content. The extent of reduction at pH 5.0 in each constituent was determined by isolating the S-carboxy-methylcysteine and measuring its specific radioactivity. The disulphide bonds in the proteins of high- and low-sulphur content from any particular fraction were reduced to the same extent. Variations between the fractions themselves were quite small, usually less than 5% and not . deviating by more than 10% from the mean. It was concluded that the cystine residues of the so-called (A+B) fraction are not confined to any particular protein component and it is inferred that they are equally distributed throughout the morphological components of wool. The apparent differences in reactivity between disulphide bonds in wool have been interpreted as resulting from an equilibrium between the SS-SH system and the reducing agents used.