Oldberg A, Heldin C H, Wasteson A, Busch C, Höök M
Biochemistry. 1980 Dec 9;19(25):5755-62. doi: 10.1021/bi00566a014.
An endoglycosidase (heparitinase) acting on heparin and heparan sulfate was partially purified (approximately 300 times) from human platelets by affinity chromatography on heparan sulfate substituted Sepharose. Only heparin-like polysaccharides were degraded by the enzyme. The susceptibility of various biosynthetic heparin intermediates indicated that the platelet heparitinase had a requirement for sulfamino but not ester sulfate groups. No activity toward other uronic acid containing glycosaminoglycans could be demonstrated. Glucuronidic but not glucosaminidic linkages in heparin or heparan sulfate were attacked by the enzyme as shown by analysis of the reducing sugar moiety in oligosaccharide products. The anticoagulant activity of heparin, determined in an antithrombin III activation assay, was markedly reduced after treatment with the heparitinase. The enzyme was released from its storage site in platelets after induction of the platelet release reaction. The physiological function of platelet heparitinase is not known but may be to modify extracellular heparin-like polysaccharides in the vascular system.
通过在硫酸乙酰肝素替代的琼脂糖上进行亲和层析，从人血小板中部分纯化了一种作用于肝素和硫酸乙酰肝素的内切糖苷酶（乙酰肝素酶）（约300倍）。该酶仅降解类肝素多糖。各种生物合成肝素中间体的敏感性表明，血小板乙酰肝素酶需要磺氨基而非硫酸酯基团。未显示出对其他含糖醛酸的糖胺聚糖有活性。通过对寡糖产物中还原糖部分的分析表明，肝素或硫酸乙酰肝素中的葡萄糖醛酸苷键而非氨基葡萄糖苷键会受到该酶的攻击。在抗凝血酶III激活试验中测定的肝素抗凝活性，在用乙酰肝素酶处理后显著降低。在诱导血小板释放反应后，该酶从血小板的储存部位释放出来。血小板乙酰肝素酶的生理功能尚不清楚，但可能是修饰血管系统中的细胞外类肝素多糖。
