Structural analysis and CCK-releasing activity of a sulphated polysaccharide from abalone (Haliotis Discus Hannai Ino) viscera

A fraction of water-soluble sulphated polysaccharide conjugate, termed AHP-2, was obtained from abalone (Haliotis Discus Hannai Ino) viscera by protease-assisted aqueous extraction followed by precipitation with ethanol and purification with gel filtration chromatography. Analysis by high performance liquid chromatography (HPLC) coupled to a TSK-gel G4000PW_XL column and gel filtration chromatography on Sepharose CL-6B indicated AHP-2 is homogenous with an average molecular weight (MW) of about 11.0 kDa. The structure of AHP-2 was revealed by chemical methods, Fourier transform infrared (FTIR) spectroscopy, and nuclear magnetic resonance (NMR) spectroscopy. Results indicated AHP-2 is a heteroglycan consisting of glucose, fucose, xylose, rhamnose and galactose with molar ratio of 1.0:2.0:3.9:6.7:7.4. The backbone of AHP-2 consists of 1,3-linked rhamnose and 1,3,6-linked galactose, with glucose, fucose, xylose and galactose of different linkage types distributing in branched chains. Meanwhile, AHP-2 was found to increase cholecystokinin (CCK) release in CCK-secreting STC-1 cells.