Immuno-chemical studies on the alkali-labile carbohydrate chains of human serum glycoproteins.

Human serum glycoproteins can be classified into those containing N-acetyl-D-galactosamine and into those lacking this hexosamine. The N-acetyl-D-galactosamine-containing serum glycoproteins have alkali-labile chains containing this hexosamine linked O-glycosidically to hydroxy amino acids. These alkali-labile chains can be demonstrated in neuraminic acid free serum glycoproteins by gas liquid chromatography and by using precipitating lectins from invertebrates and plants. They are represented by two chains, one containing only N-acetyl-D-galactosamine, the other with D-galactose linked (1--3) beta-glycosidically to this hexosamine forming a disaccharide. Serologically these two chains, which usually occur together on one molecule, can be characterized by their reaction with lectins from Helix pomatia (anti-A like) and from Agaricus bisporus and Arachis hypogaea (anti-TF specificity).