Structure of carbohydrate chain of a thrombin-like protease from the venom of Agkistrodon halys brevicaudus stejneger snake

摘要

The structure of the carbohydrate chain of kangshuanmei, a thrombin-like serine protease isolated from Agkistrodon halys brevicaudus stejneger snake venom, was determined. The carbohydrate content of the kangshuanmei was 18%. The sugar composition was analyzed by the acid hydrolysis followed by aminobenzoic ethyl ester labeling. Galactose, N-acetylglucosamin, mannose, and fucose were detected, indicating that the binding carbohydrate chain is asparagine-linked type oligosaccharides. N-Acetylneuraminic acid located at non-reduced terminal of the carbohydrate chain was identified by neuraminidase digestion. The carbohydrate chain moiety was separated from kangshuanmei by hydrazynolysis treatment followed by aminobenzoic octyl ester (ABOE) labeling. The isolated ABOEmodified carbohydrate chain was compared to the asparagine-linked type standard oligosaccharides. The carbohydrate chains were consisted of sialylated bi(39.4%)-, tri(50.4%)- and tetra(10.2%)- antennary lactosamins complex containing fucose. The structure of the conjugated carbohydrate chain of kangshuanmei was significantly different from that of thrombin, which has a bisected antennary structure of oligosaccharide.