Hendler R W, Shrager R I
Laboratory of Cell Biology, National Heart, Lung and Blood Institute, Bethesda, Maryland 20892.
J Bioenerg Biomembr. 1987 Oct;19(5):551-69. doi: 10.1007/BF00770037.
Krab et al. (1984) have recently tried to resolve the long-standing controversy as to whether the mechanistic H+/O coupling ratio for electrons passing through sites II and III of the mammalian electron transport chain to O2 is 6 or 8. Using a mathematical model they concluded that the higher number reported by Costa et al. (1984) was an overestimate because of the unaccounted for delayed response of the O2 electrode. Responding to criticisms of Lehninger et al. (1985), they have recently used (Krab and Wikström, 1986) an improved mathematical model which shows that the higher number found by Costa et al. was probably due to an inadequate accounting for the effects of the proton leak process which accompanies the translocation process. The impression is left that the situation is now resolved in favor of the lower number. We agree that the procedures of Costa et al. do not properly account for the leak process, and provide further evidence in this paper of the magnitude of the problem. However, we disagree that the number 6.0, favored by Wikström et al., rests on any more solid experimental support. We provide evidence here for this conclusion and raise the question as to whether or not any unique, fixed, integral number exists for the H+/O ratio accompanying the oxidation of a particular substrate.
克拉布等人（1984年）最近试图解决一个长期存在的争议，即哺乳动物电子传递链中电子通过位点II和III传递给氧气时，其机制性的H⁺/O偶联比是6还是8。他们使用一个数学模型得出结论，科斯塔等人（1984年）报告的较高数字是高估了，原因是未考虑到氧电极的延迟响应。针对莱宁格等人（1985年）的批评，他们最近（克拉布和维克斯特伦，1986年）使用了一个改进的数学模型，该模型表明科斯塔等人发现的较高数字可能是由于在转运过程中未充分考虑伴随质子泄漏过程的影响。给人的印象是，现在情况已得到解决，倾向于较低的数字。我们同意科斯塔等人的方法没有恰当地考虑泄漏过程，并在本文中提供了关于该问题严重程度的进一步证据。然而，我们不同意维克斯特伦等人支持的6.0这个数字有更可靠的实验依据。我们在此提供了支持这一结论的证据，并提出一个问题，即伴随特定底物氧化的H⁺/O比是否存在任何唯一、固定的整数。
