Variation of the glycosylation of human pancreatic bile‐salt‐dependent lipase

Glycoproteins of human pancreatic juice were characterized by means of lectins after electrophoresis and electrotransfer to nitrocellulose membranes. For the detected glycoproteins, only a 100-kDa glycoprotein varied in the pancreatic juice from a normal patient (i.e. without any pancreatic disorder) compared to the pancreatic juice from a patient suffering from chronic pancreatitis. This protein, which is the only protein in human pancreatic juice which is O-glycosylated and N-glycosylated, was identified as the bile-salt-dependent lipase. Among the glycosylated proteins present in human pancreatic juice, only the glycosylation of bile-salt-dependent lipase differs between individuals. The enzyme was isolated either from normal or pathological human pancreatic juices. The purified variants have an identical molecular mass and amino-acid composition. As suspected from lectin affinity studies, the oligosaccharide composition differs between the variants. The structure of the N-linked oligosaccharides of the variant from the pancreatic juice of a normal donor correlated with complete processing and maturation of a complex-type N-glycan. Alteration of the maturation process can be detected for a bile-salt-dependent-lipase variant from a patient suffering with chronic pancreatitis, since the carbohydrate composition is compatible with the predominance of hybrid or high-mannose-type structures. The amount of sugar involved in O-glycosylation associated with the peanut agglutinin reactivity suggests the presence of 12-14 minimal Gal beta 1-->3GalNac-->T/S O-glycan structures which are sialylated and fucosylated. The amount of sugar involved in the O-linked oligosaccharide structure appears to be unchanged in the variants isolated from the pathological pancreatic juice.