Nakatani H
Faculty of Agriculture, Kyoto University, Japan.
Biopolymers. 1999 Aug;50(2):145-51. doi: 10.1002/(SICI)1097-0282(199908)50:2<145::AID-BIP3>3.0.CO;2-2.
4-alpha-Glucanotransferase (GTase, D-enzyme) catalyzes disproportionation between two short polymers of maltooligosaccharides linked by alpha-1,4-glucoside bonds. Using action modes of the potato GTase for the donor and acceptor substrates, the Monte Carlo method was applied to simulate the GTase reaction. The simulation starts from a single enzyme molecule and a finite number (10(5)) of substrate molecules. All selection processes were performed using random numbers produced by computer. The initial substrates were from trimer to 10-mer. In every case, the final stage was the steady-state distribution of polymers. The steady-state distribution by the potato GTase reaction was different from those by the hypothetical random disproportionation reaction. The simulated data from the reaction of potato GTase and trimer almost quantitatively agreed with experimental data. The mechanism of the GTase reaction was accumulation of probabilistic processes and was well simulated by the Monte Carlo method. GTase randomizes the overall distribution of chain length of the substrate. Therefore the GTase reaction is an entropy-driven process.
4-α-葡聚糖转移酶（GTase，D-酶）催化由α-1,4-糖苷键连接的两个麦芽寡糖短聚合物之间的歧化反应。利用马铃薯GTase对供体和受体底物的作用模式，应用蒙特卡罗方法模拟GTase反应。模拟从单个酶分子和有限数量（10⁵）的底物分子开始。所有选择过程均使用计算机生成的随机数进行。初始底物为三聚体至十聚体。在每种情况下，最终阶段都是聚合物的稳态分布。马铃薯GTase反应的稳态分布与假设的随机歧化反应的稳态分布不同。马铃薯GTase与三聚体反应的模拟数据几乎与实验数据定量一致。GTase反应的机制是概率过程的积累，并且通过蒙特卡罗方法得到了很好的模拟。GTase使底物链长的整体分布随机化。因此，GTase反应是一个熵驱动的过程。
