Barnett J E
Biochem J. 1971 Jul;123(4):607-11. doi: 10.1042/bj1230607.
The enzymic hydrolysis of glycosyl fluorides is conveniently followed by using a pH-stat. Reactions involving glucosyl or galactosyl fluorides can also be followed by using glucose oxidase or galactose oxidase respectively. The pH-stat allows the rapid assay of intestinal alpha-glucosidase in crude homogenates. Use of glycosyl fluorides as substrates for glycosidases facilitates the polarimetric or g.l.c. determination of the anomeric nature of the initial product of hydrolysis. Hydrolysis by fungal amyloglucosidase proceeds with inversion of configuration whereas that by yeast and rat intestinal alpha-glucosidase, coffee-bean alpha-galactosidase and almond emulsin beta-glucosidase proceeds with retention of configuration. beta-d-Glucopyranosyl azide was not a detectable substrate for almond emulsin beta-d-glucosidase.
使用pH计可以方便地跟踪糖基氟化物的酶促水解过程。涉及葡萄糖基或半乳糖基氟化物的反应,也可以分别使用葡萄糖氧化酶或半乳糖氧化酶进行跟踪。pH计可用于快速测定粗匀浆中肠道α-葡萄糖苷酶的活性。使用糖基氟化物作为糖苷酶的底物,便于通过旋光法或气相色谱法测定水解初始产物的异头物性质。真菌糖化酶水解时构型发生转化,而酵母和大鼠肠道α-葡萄糖苷酶、咖啡豆α-半乳糖苷酶和杏仁乳β-葡萄糖苷酶水解时构型保持不变。β-D-吡喃葡萄糖基叠氮化物不是杏仁乳β-D-葡萄糖苷酶可检测的底物。