NOVEL SULFATED OLIGOSACCHARIDES CONTAINING 3-O-SULFATED GLUCURONIC-ACID FROM KING CRAB CARTILAGE CHONDROITIN SULFATE-K - UNEXPECTED DEGRADATION BY CHONDROITINASE ABC

We prepared a series of oligosaccharides from king crab cartilage chon droitin sulfate K after exhaustive digestion with testicular hyaluroni dase, and determined the structures of four tetrasaccharides and a pen tasaccharide by fast atom bombardment mass spectrometry, high performa nce liquid chromatography analysis of chondroitinase AC-II digests, an d 500-MHz H-1 NMR spectroscopy. The tetrasaccharides shared the common core structure GlcA beta 1-3GalNAc beta 1-4GlcA beta 1-3GalNAc with v arious sulfation profiles. One structure was GlcA beta 1-3GalNAc(4S)be ta 1-4GlcA beta 1-3GalNAc(4S), whereas three of them have the followin g hitherto unreported structures including a novel glucuronate 3-O-sul fate: GlcA(3S)beta 1-3GalNAc(4S)beta 1-4GlcA beta 1-3GalNAc(4S), GlcA beta 1-3GalNAc(4S)beta 1-4GlcA(3S)beta 1-3GalNAc(4S), and GlcA (3S)bet a 1-3GalNAc(4S)beta 1-4GlcA(3S)beta 1-3GalNAc(4S) where 3S or 4S repre sents 3-O- or 4-O-sulfate, respectively. The structure of the pentasac charide was determined as GlcA(3S)beta 1-3GalNAc(4S)beta 1-4GlcA(3S)be ta 1-3GalNAc(4S)beta 1-4GlcA. Chondroitinase ABC digestion of the tetr asaccharides with GlcA(3S) at the internal position destroyed the disa ccharide unit containing GlcA(3S) derived from the reducing side and r esulted in only the disaccharide unit from the non-reducing side. In c ontrast, these tetrasaccharides remained totally resistant to chondroi tinase AC-II. The results indicated that it is necessary to reevaluate the disaccharide composition of chondroitin sulfate poly- or oligosac charides purified from various biological sources, since they were usu ally determined after chondroitinase ABC digestion, It is probable tha t the structures containing GlcA(3S) would not have been detected.