Structural characterization and osteogenic bioactivity of a sulfated polysaccharide from pacific abalone (Haliotis discus hannai Ino)

Bone morphogenic protein-2 (BMP-2) is known to promote osteogenesis. To find novel adjuvants to enhance the activity of BMP-2, the present study investigated the structure BMP-2-induced osteogenic activity of a water-soluble polysaccharide from the gonad of pacific abalone (Haliotis discus hannai Ino) named AGSP. Through analysis of aldobiouronic acids released from AGSP, monosaccharide composition comparison of AGSP and its reduced product, and methylation analysis and NMR analysis of AGSP and its desulfated derivative, the main structure residue of AGSP was determined as -> 3)-GlcA(1 -> 3)-Gal(1 -> with sulfated branches comprised of prevelant Gal and minor Glc, and -> 4)-beta-GlcA(1 -> 2)-alpha-Man(1 -> residue was also found. AGSP possessed a sulfate content of 12.4% with a relative molecular weight of 6.6 kDa. AGSP strengthened alkaline phosphatase activity induced by BMP-2 in a dose dependent manner at 10-200 mu g/mL with 425% enhancement being observed at 200 mu g/mL, indicating AGSP could be an adjuvant candidate to enhance osteogenic activity of BMP-2.