Discrimination of gamma-glutamyltranspeptidase from normal and carcinomatous pancreas

Two types of gamma-glutamyltranspeptidase (gamma-GTP) were identified in normal human pancreas, but ductal cell carcinomas of the pancreas showed only one type on analysis with polyacrylamide gel electrophoresis, anion exchange column chromatography, concanavalin A affinity chromatography and isoelectric focusing. gamma-GTP from carcinoma tissue was almost identical to the sialic acid-rich type of normal pancreatic gamma-GTP, and our methods did not evidence a difference between the two. However, E-PHA lectin column chromatography demonstrated differences in their elution pattern. Compared with normal pancreatic gamma-GTPs, the elution pattern of the carcinoma gamma-GTP was slowly delayed by the E-PHA lectin column. This finding suggests the presence of a bisecting N-acetylglucosamine-rich sugar chain in pancreatic carcinoma gamma-GTP, as well as the possible presence of a different sugar structure in the carcinoma gamma-GTP.