Ospanov R V, Kochetov G A, Kurganov B I
Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, 119992, Moscow, Russia.
Biochemistry (Mosc). 2007 Jan;72(1):84-92. doi: 10.1134/s0006297907010105.
The two-step mechanism of interaction of thiamine diphosphate (ThDP) with transketolase (TK) has been studied: TK + ThDP <--> TK...ThDP <--> TK*-ThDP. The scheme involves the formation of inactive intermediate complex TK...ThDP followed by its transformation into catalytically active holoenzyme, TK*-ThDP. The dissociation and kinetic constants for individual stages of this process have been determined. The values of forward and backward rate constants change in the presence of the donor substrate hydroxypyruvate. This finally leads to an increase in the overall affinity of the coenzyme to TK.
已对硫胺素二磷酸（ThDP）与转酮醇酶（TK）相互作用的两步机制进行了研究：TK + ThDP <--> TK...ThDP <--> TK*-ThDP。该机制包括形成无活性的中间复合物TK...ThDP，随后将其转化为具有催化活性的全酶TK*-ThDP。已确定了该过程各个阶段的解离常数和动力学常数。在供体底物羟基丙酮酸存在的情况下，正向和反向速率常数的值会发生变化。这最终导致辅酶对TK的总体亲和力增加。
