Hyman secretory component — III: Carbohydrates, amino acids and N-terminal sequence

Abstract Free secretory component purified from colostrum had a total carbohydrate content of 18·6 per cent by weight. Its amino acid composition showed lack of methionine, a relatively low content of the basic amino acids lysine and arginine, and a fairly high content of half cystine (3·3 residues per 100). Within the N-terminal amino acid sequence no heterogeneity was found, and there was no sequence homology with immunoglobulin light or heavy chains.