The Influence of Sulphur-Containing Amino Acids on the Biosynthesis of High-Sulphur Wool Proteins

Abstract

The sulphur content of wool can vary within the range of about 2·7-4·2% depending on the diet of the sheep. The lower limit may represent a limiting fundamental structure for wool as it has not been possible to produce wool of sulphur content lower than 2·7% during sulphur-deprivation experiments. There is a highly significant linear relationship between the sulphur content of wool and its content of high-sulphur proteins. The major part of this variation in sulphur content is due to alterations in the extent of biosynthesis of proteins of extremely high sulphur content having about one-third of the amino acid residues presen1, as half cystine. The biosynthesis of these proteins may be under separate metabolic control for they can be produced at maximum rate under conditions where the synthesis of other highsulphur proteins is partly inhibited by a sulphur-deficient diet or by high levels of DL-methionine supplementation