Proton-translocating transhydrogenases, reducing NADP(+) by NADH through hydride transfer, are membrane proteins utilizing the electrochemical proton gradient for NADPH generation. The enzymes have important physiological roles in the maintenance of e.g. reduced glutathione, relevant for essentially all cell types. Following X-ray crystallography and structural resolution of the soluble substrate-binding domains, mechanistic aspects of the hydride transfer are beginning to be resolved. However, the structure of the intact enzyme is unknown. Key questions regarding the coupling mechanism, i.e., the mechanism of proton translocation, are addressed using the separately expressed substrate-binding domains. Important aspects are therefore which functions and properties of mainly the soluble NADP(H)-binding domain, but also the NAD(H)-binding domain, are relevant for proton translocation, how the soluble domains communicate with the membrane domain, and the mechanism of proton translocation through the membrane domain.

中文翻译：

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质子易位转氢酶：未解决和有争议问题的更新。

质子转运转氢酶，通过氢化物转移通过 NADH 减少 NADP(+)，是利用电化学质子梯度产生 NADPH 的膜蛋白。这些酶在维持例如还原型谷胱甘肽中具有重要的生理作用，这与基本上所有细胞类型相关。在 X 射线晶体学和可溶性底物结合域的结构解析之后，氢化物转移的机械方面开始得到解决。然而，完整酶的结构是未知的。关于耦合机制的关键问题，即质子易位机制，使用单独表达的底物结合域来解决。因此，重要的方面是主要可溶性 NADP(H) 结合域的功能和特性，还有 NAD(H) 结合域，