Abstract
In our previous experiment, immune lactoglobulin of cow colostrum were digested with proteinase (Pronase-P), and the glycopeptides were isolated from the digested material by gel filtration on Sephadex. It was then fractionated by DEAE cellulose chromatography.
In the present experiment we report the several properties of these glycopeptides, namely, amino acid compositions, carbohydrate compositions and their electrophoretic properties. The analysis of two glycopeptides indicates the presence of approximately 10 residues of mannose, 7 residues of galactose, 2 residues of fucose and 9 or 11 residues of glucosamine. One of them contains 2 residues of sialic acid but the other contains no sialic acid. Amino acid analysis indicates that they contain 2residues of serine, 2 residues of aspartic acid and 2 residues of threonine.
Except the occurrence of sialic acid in one glycopeptide and its absence from the other, the carbohydrate composition and the amino acid composition of these glycopeptides are quantitatively alike. The similarity of the glycopeptides suggest that immune globulin of cow colostrum has only one carbohydrate chain and the sialic acid was lost during isolation of the glycopeptide. The difference of electrophoretic properties and chromatographic properties are depend on the sialic acid.
