Studies On The Extraction, Isolation And Structure Of Glycosaminogly From Lophius Litulon Bones

In this paper, the extraction and isolation of glycosaminogly (GAG)from Lophius litulon bones was examined, and the physicochemicalcharacters and structural properties of the fraction GAGâ… wereanalyzed.The extraction conditions include salt anion strength, salt releasingcondition and enthanol deposition condition. The optimum process wasextraction with 20% NaCl, and the solution removed protein at 90℃,pH7.8, then centrifuging to remove the protein again at pH2.5, finallyusing 70% (v/v) enthanol to deposit the GAG.Both GAGs extracted from Lophius litulon head and vertebra bonesare white powder; the yield rates of the process are 3.47%, 1.24%separately. The hexosamine content in the GAG products are 30.12%and 32.60%. IR and CE show that both of the products contain two kindsGAG components. The calcium acetate-enthanol method and CPC method were used toseparate the GAG from Lophius litulon head bones. Theacetate-enthanol method is simple, convenient and suitable for Lophiuslitulon GAG. Each method could separate the GAG into two componentsnamed GAG1 and GAG2. GAG2 was further separated into threefractions GAGâ… ,GAGâ…¡and GAGâ…¢. GAGâ… was the major fraction,which took up 55.67%. GAGâ…¡and GAGâ…¢took up 30.23%,6.54%respectively.The physicochemical study showed that GAGâ… is mono-fraction,which can be well digested by chondroitinase ABC at 37℃in 2 hours. Itcontains H₂O (8.88%), hexosamine (30.12%), uronic acid (31.40%), SO₄(12.69%), and the rate of SO₃: COO^- is 0.97:1.Structural analysis showed that GAGâ… is a GAG like CS. Itsmolecular weight was 4×10⁶. It was composed ofβ-D-galactose,β-D-N-acetylgalactosamine andβ-D-Glucuromic acid.The mole rate ofthem is 0.09:1.19:1. Acetylgalactosamine and glucuromic acid combineto form repeating disaccharide units. And the galactose may locate at theprotein-saccharides linkage region. The saccharide chains of GAGâ… aremainly composed of the repeating unitsΔGlcUA-[1→3]- GalNAc-6SandΔGlcUA-[1→3]- GalNAc-4S at the mole rate 2.01:1, while thechains also contain a little galactose and three unknown componentsX₁(3.13%), X₂(5.00%), X₃(5.23%). The MS data shows that X₁ contains SO₄, X₂ may be a monosulfated disaccharide, X₃ maybeΔGlcUA-[1→3]-GalNAc.