Differential reactivity of two types of N-glycolyneuraminic acid dimers toward enzymatic and nonenzymatic hydrolysis of their interketosidic linkages.
Differential reactivity of two types of N-glycolyneuraminic acid dimers toward enzymatic and nonenzymatic hydrolysis of their interketosidic linkages.
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两种类型的 N-糖基神经氨酸二聚体对其酮苷间键的酶促和非酶促水解的不同反应性。
DOI：
10.1006/bbrc.1994.2748
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发表时间：
1994
影响因子：
3.1
通讯作者：
Inoue,Y
中科院分区：
文献类型：
--
作者：
Kitazume,S;Kitajima,K;Inoue,S;Troy2nd,FA;Lennarz,WJ;Inoue,Y
本文研究了酸和唾液酸酶催化水解Neu 5Gc α2→5-O-羟乙酰Neu 5Gc和Neu 5Gc α2→ 8 Neu 5Gc的反应动力学。前一个序列最近被确定在聚唾液酸链的唾液酸丰富的糖蛋白分离出的两个不同物种的海胆的卵冻外套，和后者以前被发现在皮质肺泡衍生的polysialoglycoprotein从虹鳟鱼卵。在pH < 3.8时，Neu 5Gc α2→5-O-羟乙酰基Neu 5Gc的水解速率大于Neu 5Gc α2→ 8 Neu 5Gc的水解速率。但在pH> 3.8时，Neu 5Gc α2→5-O-乙醇酰Neu 5Gc比Neu 5Gc α2→ 8 Neu 5Gc更稳定。这些发现表明分子内的一般酸催化对α2→5-酮苷键的不稳定性有较大贡献。与Neu 5Gc α 2→ 8 Neu 5Gc相比，Neu 5Gc α2→5-O羟乙酰Neu 5Gc是产脲节杆菌、产气荚膜梭菌和霍乱弧菌唾液酸酶的不良底物。Neu5Gcα2→5-OglycolylNeu5Gc对A.尿素酶
The kinetics of acid- and sialidase-catalyzed hydrolysis of the interketosidic linkages of two different disialic acids, Neu5Gcα2→5-OglycolylNeu5Gc and Neu5Gcα2→8Neu5Gc, were studied. The former sequence was recently identified in the polysialic acid chains of a sialic acid-rich glycoprotein isolated from the egg jelly coat of two different species of sea urchins, and the latter was previously found in the cortical alveolar-derived polysialoglycoprotein from rainbow trout eggs. At pH values < 3.8, the rate of hydrolysis of Neu5Gcα2→5-OglycolylNeu5Gc was greater than that of Neu5Gcα2→8Neu5Gc. Paradoxically, however, Neu5Gcα2→5-OglycolylNeu5Gc was more stable than Neu5Gcα2→8Neu5Gc at pH values > 3.8. These findings indicate a greater contribution of intramolecular general acid catalysis to the lability of the α2→5-ketosidic linkage. Neu5Gcα2→5-OglycolylNeu5Gc was a poor substrate forArthrobacter ureafaciens,Clostridium perfringens, andVibrio choleraesialidases, in contrast to Neu5Gcα2→8Neu5Gc. Neu5Gcα2→5-OglycolylNeu5Gc was essentially resistant to hydrolysis byA. ureafacienssialidase.