Lepperdinger G, Strobl B, Kreil G
Institute of Molecular Biology, Austrian Academy of Sciences, Billrothstrabetae 11, A-5020 Salzburg, Austria.
J Biol Chem. 1998 Aug 28;273(35):22466-70. doi: 10.1074/jbc.273.35.22466.
Using Expressed Sequence Tags (ESTs) deposited in the data banks, a cDNA has been assembled that encodes a protein related to the hyaluronidases from bee venom and mammalian sperm. Expression of this cDNA yielded a polypeptide termed HYAL2, which is located in lysosomes. The HYAL2 protein was shown to have hyaluronidase activity below pH 4. However, it only hydrolyzed hyaluronan of high molecular mass from umbilical cord, rooster comb, and a Streptococcus strain. The reaction product was a polysaccharide of about 20 kDa, which was further hydrolyzed to small oligosaccharides by the sperm hyaluronidase. Conversely, hyaluronan fragments from vitreous humor, which had a molecular mass of about 20 kDa, were not cleaved by the HYAL2 enzyme to any detectable extent. These results provide evidence for the existence of structural domains in hyaluronan, which are resistant to the action of this enzyme. The structural and functional implications of these findings are discussed.
利用数据库中存储的表达序列标签（ESTs），组装出了一个编码与蜂毒和哺乳动物精子中的透明质酸酶相关蛋白质的cDNA。该cDNA的表达产生了一种名为HYAL2的多肽，它定位于溶酶体中。研究表明，HYAL2蛋白在pH值低于4时具有透明质酸酶活性。然而，它仅能水解来自脐带、公鸡鸡冠和一种链球菌菌株的高分子量透明质酸。反应产物是一种约20 kDa的多糖，该多糖会被精子透明质酸酶进一步水解为小寡糖。相反，来自玻璃体液的分子量约为20 kDa的透明质酸片段在任何可检测的程度上都不会被HYAL2酶切割。这些结果为透明质酸中存在对该酶作用具有抗性的结构域提供了证据。讨论了这些发现的结构和功能意义。
