Investigation of the mechanism of action of pyrogallol-phloroglucinol transhydroxylase by using putative intermediates.
Investigation of the mechanism of action of pyrogallol-phloroglucinol transhydroxylase by using putative intermediates.
复制标题
使用假定的中间体研究邻苯三酚-间苯三酚转羟化酶的作用机制。
作者：
Csaba Paizs;U. Bartlewski;J. Rétey
焦性没食子酚-间苯三酚转羟酶是一种含多巴胺的酶，催化芳香族化合物厌氧降解的关键反应。在体外，酶促反应需要1，2，3，5-四羟基苯作为助催化剂，并且在不与来自水的羟基交换的情况下发生羟基转移。为了验证我们先前的提议，即羟基的转移通过2，4，6，3 '，4'，5 '-六羟基二苯醚作为中间体发生，我们合成了该化合物并研究了其性质。我们还描述了3，4，5，3 '，4'，5 '-六羟基二苯醚的合成和表征。这两种化合物在体外均可以替代助催化剂。这表明二苯醚可以侵入活性中心并启动催化循环。最近，转羟酶（TH）的X射线晶体结构被证实16，它支持提出的羟基转移机制。
Pyrogallol-phloroglucinol transhydroxylase from Pelobacter acidigallici, a molybdopterin-containing enzyme, catalyzes a key reaction in the anaerobic degradation of aromatic compounds. In vitro, the enzymatic reaction requires 1,2,3,5-tetrahydroxybenzene as a cocatalyst and the transhydroxylation occurs without exchange with hydroxy groups from water. To test our previous proposal that the transfer of the hydroxy group occurs via 2,4,6,3',4',5'-hexahydroxydiphenyl ether as an intermediate, we synthesized this compound and investigated its properties. We also describe the synthesis and characterization of 3,4,5,3',4',5'-hexahydroxydiphenyl ether. Both compounds could substitute for the cocatalyst in vitro. This indicates that the diphenyl ethers can intrude into the active site and initiate the catalytic cycle. Recently, the X-ray crystal structure of the transhydroxylase (TH) was published16 and it supports the proposed mechanism of hydroxy-group transfer.