SELECTIVE HYDROLYSIS OF CHONDROITIN SULFATES BY HYALURONIDASE
SELECTIVE HYDROLYSIS OF CHONDROITIN SULFATES BY HYALURONIDASE
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DOI：
10.1021/bi00297a028
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发表时间：
1984-01-01
期刊：
影响因子：
2.9
通讯作者：
CONRAD, HE
中科院分区：
文献类型：
--
作者：
KNUDSON, W;GUNDLACH, MW;CONRAD, HE
将4-硫酸软骨素和6-硫酸软骨素与睾丸透明质酸酶在过量β-葡萄糖苷酸酶存在下孵育。β-葡萄糖醛酸酶导致从由透明质酸酶作用形成的寡糖中快速去除非还原末端β-D-葡萄糖醛酸基残基，破坏透明质酸酶的糖基化活性所需的寡糖受体，并以等于透明质酸酶催化的水解率的速率释放游离D-葡萄糖醛酸。透明质酸酶在37度时测定。C在0.05M氯化钠、0.05M Na2SO4和0.1M乙酸钠存在下，4-硫酸软骨素的水解率是6-硫酸盐软骨素的1.5倍。透明质酸酶在45度时测定。在0.06M醋酸钠中，pH为6，4-硫酸软骨素的水解率是6-硫酸软骨素的8倍。在pH值为5的条件下，4-硫酸软骨素转化为三糖和五糖的混合物，而6-硫酸软骨素主要转化为五糖和七糖的混合物，只有少量的三糖。在pH值为6的条件下，4-硫酸软骨素转化为五糖和七糖的混合物，只有少量的三糖，而6-硫酸软骨素的产物是聚合度在7-25个单糖之间的低聚糖混合物。对反应产物的末端基团分析表明，两种底物均优先在4-硫酸双糖的糖苷键上裂解。讨论了在较高pH条件下增强透明质酸酶的底物选择性在分析硫酸软骨素结构中的应用。
Chondroitin 4-sulfate and chondroitin 6-sulfate were incubated with testicular hyaluronidase in the presence of excess .beta.-glucuronidase. The .beta.-glucuronidase caused rapid removal of the nonreducing terminal .beta.-D-glucuronosyl residues from the oligosaccharides formed by the action of the hyaluronidase, destroying the oligosaccharide acceptors required for the transglycosylation activity of hyaluronidase and releasing free D-glucuronic acid at a rate that was equal to the rate of the hyaluronidase-catalyzed hydrolysis. When hyaluronidase was assayed at 37.degree. C in the presence of 0.05 M NaCl, 0.05 M Na2SO4 and 0.1 M sodium acetate at pH 5, chondroitin 4-sulfate was hydrolyzed at 1.5 times the rate found for chondroitin 6-sulfate. When hyaluronidase was assayed at 45.degree. C in 0.06 M sodium acetate at pH 6, chondroitin 4-sulfate was hydrolyzed at 8 times the rate observed for chondroitin 6-sulfate. Under the pH 5 conditions, the chondroitin 4-sulfate was converted to a mixture of tri- and pentasaccharides, while the chondroitin 6-sulfate was converted primarily to a mixture of penta- and heptasaccharides, with only a small amount of trisaccharide. Under the pH 6 conditions, the chondroitin 4-sulfate was converted to a mixture of penta- and heptasaccharides, with only a small amount of trisaccharide, but the products from chondroitin 6-sulfate were a mixture of oligosaccharides ranging in degree of polymerization from 7-25 monosaccharides per oligosaccharide. End-group analyses of the products formed at pH 6 showed that both substrates were cleaved preferentially at the glycosidic bonds of the 4-sulfated disaccharides. The use of the enhanced substrate selectivity of hyaluronidase at the higher pH in the analysis of chondroitin sulfate structures is discussed.