Azzone G F, Bragadin M, Pozzan T, Antone P D
Biochim Biophys Acta. 1977 Jan 6;459(1):96-109. doi: 10.1016/0005-2728(77)90012-3.
Delta approximately muH has been determined in steady state mitochondria by measuring the magnitude of delta pH on the distribution of acetate and of deltapsi on the distribution of K+, tetraphenylphosphonium, Ca2+, Sr2+ and Mn2+. (1) The matrix concentration of divalent cations has been calculated from the total cation uptake, from the increase of matrix volume and from the ESR sextet signal of Mn(H2O)L2+. The [cat2+]i based on osmotic data is about five times higher than that based on ESR measurements. The [cat2+]i based on total uptake is much higher than that based on osmotic data at low cation/protein ratios. (2) In the presence of 10 mM acetate the maximal deltapsi on Ca2+ is about 130 mV and on Sr2+ is 95 mV. Deltapsi on Mn2+ is 91 or 109 mV, according to whether [cat2+-a)i is calculated from ESR or osmotic data. Under the same conditions, deltapH is about 60 mV. Hence delta approximately muH on divalent cations is between 151 and 190 mV. (3) Deltapsi on K+, in valinomycin treated mitochondria with 10 mM acetate or 2 mM Pi, drops from 200 mV, at low [K+]0 to almost zero parallel to the increase of [K+]0. DeltapH is 30 mV at low [K+]0 and about 42 mV at 600 muM K+. Hence delta approximately muH drops from 22m mV lower values with the increase of [K+]0. (4) Maximal deltapsi on triphenylmethylphosphonium is 140 mV. (5) When delta approximately muH is measured simultaneously on divalent cations and on K+, the values on K+ tend to approach those on Ca2+ while those on Sr2+ are about 50 mV lower. (6) It is concluded that the steady state mitochondrial energy potential is equivalent to a delta approximately muH between 150 and approx. 190 mV.
通过测量乙酸盐分布上的ΔpH值以及钾离子、四苯基鏻离子、钙离子、锶离子和锰离子分布上的Δψ，已在稳态线粒体中测定了约为μH的Δ值。(1) 二价阳离子的基质浓度已根据总阳离子摄取量、基质体积的增加以及Mn(H₂O)L₂⁺的电子自旋共振六重峰信号计算得出。基于渗透数据的[cat²⁺]i比基于电子自旋共振测量的约高五倍。在低阳离子/蛋白质比率下，基于总摄取量的[cat²⁺]i远高于基于渗透数据的。(2) 在存在10 mM乙酸盐的情况下，钙离子上的最大Δψ约为130 mV，锶离子上的为95 mV。根据[cat²⁺-a)i是从电子自旋共振还是渗透数据计算得出，锰离子上的Δψ为91或109 mV。在相同条件下，ΔpH约为60 mV。因此，二价阳离子上的约为μH的Δ值在151至190 mV之间。(3) 在经缬氨霉素处理的线粒体中，存在10 mM乙酸盐或2 mM磷酸时，钾离子上的Δψ从低[K⁺]₀时的200 mV降至几乎为零，与[K⁺]₀的增加平行。低[K⁺]₀时的ΔpH为30 mV，600 μM钾离子时约为42 mV。因此，约为μH的Δ值随着[K⁺]₀的增加从22 mV降至更低值。(4) 三苯甲基鏻离子上的最大Δψ为140 mV。(5) 当同时在二价阳离子和钾离子上测量约为μH的Δ值时，钾离子上的值倾向于接近钙离子上的值，而锶离子上的值约低50 mV。(6) 得出结论，稳态线粒体能量势相当于约150至约190 mV之间的约为μH的Δ值。
