可可毛色二孢β-葡萄糖苷酶作用机制的动力学分析

Kinetic analysis of the mechanism of action of beta-glucosidase from Botryodiplodia theobromae Pat.

Umezurike G M

Biochim Biophys Acta. 1975 Jul 27;397(1):164-78. doi: 10.1016/0005-2744(75)90190-4.

Abstract

The kinetic mechanism of beta-glucosidase (beta-D-glucoside glucohydrolase, EC 3.2.1.21) of Botryodiplodia theobromae Pat. has been studied in the presence of competing glucosyl acceptors. 2. Glycerol, fructose, sucrose, cellobiose and to a much lesser extent, maltose can act as glucosyl acceptors, apart from water. 3. Evidence confirming and supporting the kinetic mechanism previously postulated (Umezurike, G.M. (1971) Biochim. Biophys. Acta. 250, 182-191) is presented. 4. A theoretical kinetic analysis of the behaviour of the enzyme in the presence of two alternative glucosyl acceptors in addition to water is found to be consistent with experimental observation, suggesting a system in which both donor and acceptors bind to the enzyme in a random fashion to form ternary complexes. 5. The results are discussed in terms of the mechanism of group-transfer reactions.

摘要

对可可球二孢菌（Botryodiplodia theobromae Pat.）的β-葡萄糖苷酶（β-D-葡萄糖苷葡糖水解酶，EC 3.2.1.21）在存在竞争性葡糖基受体的情况下的动力学机制进行了研究。2. 除水之外，甘油、果糖、蔗糖、纤维二糖以及程度小得多的麦芽糖都可作为葡糖基受体。3. 给出了证实并支持先前假定的动力学机制（乌梅祖里克，G.M.（1971年）《生物化学与生物物理学报》250卷，182 - 191页）的证据。4. 对该酶在除水之外还存在两种替代葡糖基受体的情况下的行为进行的理论动力学分析被发现与实验观察结果一致，这表明存在一种供体和受体都以随机方式与酶结合以形成三元复合物的体系。5. 根据基团转移反应的机制对结果进行了讨论。