The binding of atractylate and carboxy-atractylate to mitochondria.
The binding of atractylate and carboxy-atractylate to mitochondria.
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白术酸和羧基白术酸与线粒体的结合。
DOI：
10.1111/j.1432-1033.1975.tb04003.x
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发表时间：
1975
期刊：
影响因子：
--
通讯作者：
Burkhard Scherer
中科院分区：
文献类型：
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作者：
Martin Klingenberg;Karin Grebe;Burkhard Scherer
35s标记的atractyate和羧基atractyate是生物合成的，用于研究这些特异性配体与牛肉心脏线粒体中ADP、ATP载体的结合。得到如下结果：1. 易位活性的抑制与atractylate [35S]结合的增加是平行的。在达到完全抑制易位后，没有观察到额外的结合，这证明了atractyate仅与载体结合。2. 两种atractyates在牛肉心脏线粒体中的最大结合位点数约为1.6 μ mol/g蛋白，并随着膜的Pi、冷冻、老化等处理而减少。结合的解离常数在atractylate Kd = 5-10(-8) M和羧基-atractylate Kd = 10(-8) M时近似为。结合的质量作用图在羧基-atractylate中呈非线性凸关系，在atractylate中呈线性关系。在非常高亲和力结合的情况下，非线性似乎是由平衡的某些延迟引起的。3. 在完整的线粒体中，苍术酸和羧基苍术酸的结合相对较快，而在老化膜中则较慢。有一个较慢和一个较快的绑定部分。4. atractyates以接近1:1的化学计量从未处理的线粒体中去除ADP。在老化和pi处理的膜中，deltaADP/deltaatractylate的比值接近0。显然，载体位点与ADP的结合对改变的敏感性要高于atractyates。假设atractyate的结合位点与ADP和ATP的结合位点相同。5. Bongkrekate阻止了两种atractyate的结合。但后加入后，由于其紧密结合的不同，只能去除四羧酸盐而不能去除羧基化合物。去除率主要依赖于bongkrekate与ADP的协同作用。6. 与[35S]atractylate的结合研究，特别是与bongkrekate的相互作用，支持了载体重定向模型，即atractylate作为一种不渗透的配体将载体的结合位点固定在外部，而与bongkrekate的结合则将载体位点转向内部。
35S-labelled atractylate and carboxy-atractylate are produced biosynthetically and used for studying the binding of these specific ligands to the ADP, ATP carrier in beef heart mitochondria. The following results are obtained. 1. Inhibition of translocation activity goes parallel to the increase of binding by [35S]atractylate. No additional binding is observed after full inhibition of translocation is reached giving evidence that atractylate binds exclusively to the carrier. 2. The maximum number of binding sites of both atractylates is about 1.6 mumol/g protein in beef heart mitochondria and decreases on treatment of the membrane by Pi, freezing, ageing, etc. The dissociation constants of the binding are approximately for atractylate Kd = 5-10(-8) M and for carboxy-atractylate Kd = 10(-8) M. The mass action plots of the concentration dependence for the binding are nonlinear-convex in particular with carboxy-atractylate and more linear with atractylate. Nonlinearity appears to be caused by some retardation of equilibration in the case of very high affinity binding. 3. The binding of atractylate and carboxy-atractylate is relatively fast in intact mitochondria and slower in aged membranes. There is a slower and a faster binding portion. 4. The atractylates remove ADP in a nearly 1:1 stoichiometry from untreated mitochondria. In aged and Pi-treated membranes the ratio deltaADP/deltaatractylate approaches 0. Obviously binding of carrier sites to ADP is more sensitive to alterations than that of the atractylates. The assumption is maintained that the binding site for atractylate is identical with that for ADP and ATP. 5. Bongkrekate prevents binding of both atractylates. However, when added after, it only removes atractylate but not the carboxy compound because of its different tight binding. The removal of atractylate depends on the synergistic effect of bongkrekate with ADP. 6. The binding studies with [35S]atractylate and in particular the interaction with bongkrekate support the reorienting carrier model in which atractylate as an impermeable ligand fixes the binding site of the carrier outside while with bongkrekate the carrier site is turned to the inside.