Hassidim M, Braun Y, Lerner H R, Reinhold L
Department of Botany, The Hebrew University of Jerusalem, Jerusalem, 91904, Israel.
Plant Physiol. 1986 Aug;81(4):1057-61. doi: 10.1104/pp.81.4.1057.
Mg(2+)-ATP-dependent H(+)-translocation has been studied in membrane vesicles derived from the roots of Gossypium hirsutum L. var. Acala San Jose 2. Establishment of a positive membrane potential was followed by measuring SCN(-) accumulation; establishment of DeltapH across the vesicle membranes by measuring quinacrine fluorescence quenching. High specificity for ATP was shown, and H(+)-translocation was oligomycin stable. The pH profile for H(+)-translocation showed an optimum at 5.5. The relationship between SCN(-) accumulation and ATP concentration was approximately Michaelian; the apparent K(m) was 0.7 millimolar. K-2-(N-morpholino)ethanesulfonic acid strongly promoted ATP-dependent SCN(-) uptake (up to 180% stimulation). The effect was not given by Na-Mes. Carbonyl cyanide p-trifluoromethoxyphenylhydrazone totally inhibited SCN(-) accumulation, both in the presence and absence of K-2(N-morpholino)ethanesulfonic acid. Vanadate at 200 micromolar inhibited SCN(-) uptake by about 10 to 40% in the absence of K(+), but more strongly in its presence (about 60%). NO(3) (-) at 100 millimolar inhibited initial rate of quinacrine quenching by about 25%. The NO(3) (-) insensitive fraction was activated by K(+); and inhibited by 200 micromolar vanadate to about 40%, provided K(+) was present. Saline conditions during the growth of the plants had no appreciable effect on the observed characteristics of H(+)-translocation.
已对源自陆地棉（Gossypium hirsutum L. var. Acala San Jose 2）根部的膜囊泡中Mg(2+) - ATP依赖性H(+)转运进行了研究。通过测量SCN(-)积累来跟踪正膜电位的建立；通过测量喹吖因荧光猝灭来跟踪跨囊泡膜的ΔpH的建立。结果显示对ATP具有高特异性，并且H(+)转运对寡霉素稳定。H(+)转运的pH曲线在5.5时显示出最佳值。SCN(-)积累与ATP浓度之间的关系近似于米氏关系；表观K(m)为0.7毫摩尔。K - 2 -（N - 吗啉代）乙磺酸强烈促进ATP依赖性SCN(-)摄取（刺激高达180%）。Na - Mes没有这种作用。羰基氰化物对三氟甲氧基苯腙在有和没有K - 2（N - 吗啉代）乙磺酸的情况下都完全抑制SCN(-)积累。在不存在K(+)的情况下，200微摩尔的钒酸盐抑制SCN(-)摄取约10%至40%，但在有K(+)存在时抑制作用更强（约60%）。100毫摩尔的NO(3) (-)抑制喹吖因猝灭的初始速率约25%。对NO(3) (-)不敏感的部分被K(+)激活；并且在存在K(+)的情况下，被200微摩尔钒酸盐抑制至约40%。植物生长期间的盐胁迫条件对观察到的H(+)转运特性没有明显影响。
