Kyte J
Nature. 1981 Jul 16;292(5820):201-4. doi: 10.1038/292201a0.
A small group of closely related proteins is responsible for all active transport in animal cells, and inorganic cations are the only substances transported by these enzymes. They share a common kinetic mechanism in which two fundamental conformations participate, each receiving and dispatching substrates from its unique side of the membrane. During transport, the cations must pass through their enzyme to cross the membrane and intense interest is currently focused on the possibility that the path which they follow lies within the interface between two discrete subunits in a dimeric structure. Although 'half-of-sites' behaviour, consistent with this hypothesis, has been reported, it is now known that systematic errors were responsible for this mistaken conclusion. The number of protomers which comprise a functional unit of active transport has not been determined.
一小群密切相关的蛋白质负责动物细胞中的所有主动运输，无机阳离子是这些酶运输的唯一物质。它们共享一种共同的动力学机制，其中两种基本构象参与其中，每种构象从膜的独特一侧接收和分配底物。在运输过程中，阳离子必须通过其酶才能穿过膜，目前人们的强烈兴趣集中在它们所遵循的路径是否位于二聚体结构中两个离散亚基之间的界面内这一可能性上。尽管已经报道了与该假设一致的“半位点”行为，但现在已知是系统误差导致了这一错误结论。构成主动运输功能单元的原体数量尚未确定。
