Evidence for a Single Active Site on Isomalto-dextranase with Hydrolysis Activities of α-1, 6- and α-1, 4-Glucosidic Linkages
Evidence for a Single Active Site on Isomalto-dextranase with Hydrolysis Activities of α-1, 6- and α-1, 4-Glucosidic Linkages
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异麦芽糖葡聚糖酶单一活性位点具有 α-1, 6- 和 α-1, 4-糖苷键水解活性的证据
DOI：
10.5458/jag.48.55
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发表时间：
2001
影响因子：
1.1
通讯作者：
S. Chiba
中科院分区：
文献类型：
--
作者：
T. Takayanagi;A. Kimura;H. Matsui;G. Okada;S. Chiba
从球形节杆菌（Arthrobacter globiformis）T6中分离得到一种异麦芽葡聚糖酶，该酶能裂解潘糖的α-1，4-糖苷键和异麦芽三糖的α-1，6-糖苷键。混合底物的动力学特征、Lineweaver-Burk曲线的线性、表观最大反应速度与底物中异麦芽三糖摩尔分数（f）的关系（f = [异麦芽三糖]/（[异麦芽三糖]+ [潘糖]））与单催化中心机理的结果一致。该酶伴随有异普鲁兰酶活性，普鲁兰被异普鲁兰酶内水解，主要释放异巴诺糖。重组E.大肠杆菌细胞也从普鲁兰多糖产生异丙糖。这是第一次从遗传学上证实该酶具有固有的异支链淀粉酶活性。
An isomalto-dextranase from Arthrobacter globiformis T6 was kinetically elucidated to be capa ble of splitting α-1, 4-glucosidic linkage of panose as well as α-1, 6-glucosidic linkage of isomalt otriose. The kinetic features of the experiments with the mixed substrates of isomaltotriose and panose, the linearity of Lineweaver-Burk plots, the dependence of the apparent maximal velocities on the mole fraction (f) of isomaltotriose in the mixed substrates, f = [isomaltotriose]/([isomaltotriose]+ [panose]) were in good agreement with those expected for a single catalytic site mecha nism. The enzyme is accompanied by isopullulanase activity, by which pullulan is endolytically hy drolyzed to release isopanose mainly. The isomalto-dextranase expressed by the recombinant E. coli cells also produced isopanose from pullulan. It was for the first time confirmed genetically that the enzyme had inherently isopullulanase activity.
使用葡萄糖氧化酶试剂测定麦芽糖酶和异麦芽糖酶活性。
影响因子：
4.1
作者：
A. Dahlqvist
通讯作者：
A. Dahlqvist