[Isolation and composition of a glycoprotein from lamb gastric mucosa]

A glycoprotein is isolated from lamb gastric mucosa. It is purified first by reduction with dithiothreitol and then by chromatography on CM-Sephadex followed by gelfiltration on Sephadex G-75. Its homogeneity is investigated by disc electrophoresis, immunoelectrophoresis, analytical ultracentrifugation and identification of the carboxy- and amino-terminal amino acids. This glycoprotein contains 56 p. cent carbohydrates, consisting of N-glycolyneuraminic acid, fucose, galactose, and hexosamines. Hexosamines and galactose are in equimolar ratio ; galactosamine and glucosamine in the ratio 1 :2. The amino acid composition shows that threonine, serine and proline account for half of the amino acid residues. The cysteine origin and function are discussed.