Woelders H, van der Velden T, van Dam K
Laboratory of Biochemistry, University of Amsterdam, The Netherlands.
Biochim Biophys Acta. 1988 Jun 15;934(1):123-34. doi: 10.1016/0005-2728(88)90127-2.
The rate of ATP synthesis (JP) in isolated rat-liver mitochondria was strongly dependent on the magnitude of the protonmotive force (delta mu H+) across the mitochondrial inner membrane. Addition of different concentrations of various uncouplers or malonate to mitochondrial incubations in State 3 led to a depression of delta mu H+ and a concomitant decrease in JP. A unique relationship between JP and delta mu H+ was obtained, which was independent of the way in which delta mu H+ was varied. This unique relationship was observed when K+ (in the presence of valinomycin) was used as a probe for delta psi. Different relationships between JP and delta mu H+ were observed when K+ was used as a probe for delta psi and when K+ was measured after separation of the mitochondria by centrifugation without silicone oil. This led to a serious underestimation of delta psi, specifically when uncouplers were present, and non-unique flow-force relationships were thus obtained. Anomalous relationships between JP and delta mu H+ were also found when TPMP+ was used as a probe for delta psi. However, in uncoupler incubations the presence of TBP- strongly affected the TPMP+ accumulation ratio without any effect on the K+ accumulation or on JP and in the presence of TBP- unique relationships between JP and delta mu H+ were again obtained. This indicates that the accumulation of TPMP+ inside the mitochondria is not a straightforward function of delta psi but also depends on conditions like the presence of TBP- or uncouplers. We conclude that there is a unique relationship between the rate of phosphorylation and the protonmotive force in mitochondria and that under some conditions the behaviour of TPMP+ is anomalous.
分离的大鼠肝脏线粒体中ATP合成速率（JP）强烈依赖于线粒体内膜两侧质子动力势（δμH+）的大小。在状态3下向线粒体孵育体系中添加不同浓度的各种解偶联剂或丙二酸会导致δμH+降低，同时JP也随之下降。得到了JP与δμH+之间的独特关系，该关系与改变δμH+的方式无关。当使用K+（在缬氨霉素存在下）作为δψ的探针时，观察到了这种独特关系。当使用K+作为δψ的探针以及在不使用硅油离心分离线粒体后测量K+时，观察到JP与δμH+之间存在不同的关系。这导致对δψ的严重低估，特别是在存在解偶联剂时，从而得到了非独特的流量-力关系。当使用TPMP+作为δψ的探针时，也发现了JP与δμH+之间的异常关系。然而，在解偶联剂孵育体系中，TBP-的存在强烈影响TPMP+的积累比率，而对K+积累或JP没有任何影响，并且在TBP-存在的情况下，再次得到了JP与δμH+之间的独特关系。这表明TPMP+在线粒体内的积累不是δψ的直接函数，还取决于TBP-或解偶联剂等条件。我们得出结论，线粒体中磷酸化速率与质子动力势之间存在独特关系，并且在某些条件下TPMP+的行为是异常的。
