Isolation and characterization of sulfated glycoprotein from human pancreatic juice

Abstract

Sulfated glycoprotein was isolated by precipitation from dialyzed human pancreatic juice and purified by ion-exchange chromatography followed by repeated gel chromatography. The sulfated glycoprotein was obtained as a sulfated glycoprotein-lipid complex by Sepharose CL-2B chromatography. Lipids aggregating with the sulfated glycoprotein were glycolipids such as ceramide trihexoside, and simple lipids such as cholesterol and cholesterol ester. This glycoprotein was resistant to digestion with mucopolysaccharidases or alpha-amylase, and consisted of 60% (w/w) protein and 40% sugars. The polypeptide core was characterized by a high content of serine, threonine, aspartic acid and glycine, but lacked cysteine. Its sugar components were N-acetylglucosamine, N-acetylgalactosamine, galactose, fucose and sialic acid. Absorption at 1240 cm-1 and 820 cm-1 by infrared spectroscopy indicated the presence of a sulfate ester group. All the carbohydrate chains of this sulfated glycoprotein, which are polydisperse and heterogeneous, were O-glycosidically linked through N-acetylgalactosamine to a protein core.