STRUCTURAL ANALYSIS OF KAPPA-CARRAGEENAN OLIGOSACCHARIDES RELEASED BY CARRAGEENASE FROM MARINE CYTOPHAGA MCA-2

Sixty-nine bacterial strains producing K-carrageenase were isolated from the soil or seaweed surface from different areas of the China Sea. These included the genera Vibrio, Cytophaga and Pseudomonas. K-Carrageenase was purified from marine Cytophaga MCA-2 by ion-exchange chromatography on Q-Sepharose Fast Flow and gel filtration on Sephacryl S 100 HR. The purified K-carrageenase exhibited a single band on SDS-PAGE with a molecular mass of 30 kDa. The molecular mass of K-carrageenase hydrolysate was examined by MALDI-TOF-MS, and the structure of each fraction was measured by 13C-NMR and IR spectroscopy. The results showed that Cytophaga MCA-2 carrageenase acts as an endo-enzyme, specifically hydrolyzing the β-glycosidic linkage between 3,6-anhydro-D-galactose and D-galactose. The main depolymerized end-products were determined as K-neocarratetraose sulfate and K-neocarrahexaose sulfate with 3-linked β-D-galactopyranose 4-sulfate as the reducing end. The enzyme may be a helpful tool to prepare carrageenan oligosacchrides.