Westerhoff H V, Melandri B A, Venturoli G, Azzone G F, Kell D B
Biochim Biophys Acta. 1984 Dec 17;768(3-4):257-92. doi: 10.1016/0304-4173(84)90019-3.
Experimental data are reviewed that are not in keeping with the scheme of 'delocalized' protonic coupling in membrane-linked free-energy transduction. It turns out that there are three main types of anomalies: (i) rates of electron transfer and of ATP synthesis do not solely depend on their own driving force and on delta mu H, (ii) the ('static head') ratio of delta Gp to delta mu H varies with delta mu H and (iii) inhibition of either some of the electron-transfer chains or some of the H+-ATPases, does not cause an overcapacity in the other, non-inhibited proton pumps. None of the earlier free-energy coupling schemes, alternative to delocalized protonic coupling, can account for these three anomalies. We propose to add a fifth postulate, namely that of the coupling unit, to the four existing postulates of 'delocalized protonic coupling' and show that, with this postulate, protonic coupling can again account for most experimental observations. We also discuss: (i) how experimental data that might seem to be at odds with the 'coupling unit' hypothesis can be accounted for and (ii) the problem of the spatial arrangement of the electrical field in the different free-energy coupling schemes.
对与膜联自由能转导中“离域”质子耦合方案不一致的实验数据进行了综述。结果表明存在三种主要类型的异常情况：（i）电子传递速率和ATP合成速率不仅取决于它们自身的驱动力和ΔμH，（ii）ΔGp与ΔμH的（“静水头”）比值随ΔμH而变化，以及（iii）抑制某些电子传递链或某些H⁺-ATP酶，不会导致其他未受抑制的质子泵出现产能过剩。早期任何替代离域质子耦合的自由能耦合方案都无法解释这三种异常情况。我们建议在“离域质子耦合”的四个现有假设基础上增加第五个假设，即耦合单元假设，并表明有了这个假设，质子耦合就能再次解释大多数实验观察结果。我们还讨论了：（i）如何解释那些看似与“耦合单元”假设相矛盾的实验数据，以及（ii）不同自由能耦合方案中电场空间排列的问题。
