ADP 是玉米胚芽鞘微粒体膜中 ATP 依赖性 H 转运的竞争性抑制剂。
ADP Is a Competitive Inhibitor of ATP-Dependent H Transport in Microsomal Membranes from Zea mays L. Coleoptiles.
机构信息
Botanisches Institut der J. W. Goethe-Universität, Siesmayerstrasse 70, 6000-Frankfurt, Federal Republic of Germany.
出版信息
Plant Physiol. 1985 Apr;77(4):881-5. doi: 10.1104/pp.77.4.881.
An anion-sensitive ATP-dependent H(+) transport in microsomal membranes from Zea mays L. coleoptiles was partially characterized using the pH gradient-dependent decrease of unprotonated neutral red. The following criteria strongly suggest a tonoplast origin of the H(+) transport observed: strict dependence on Cl(-); inhibition by SO(4) (2-) and NO(3) (-); insensitivity against vanadate, molybdate, and azide; reversible inhibition by CaCl(2) (H(+)/Ca(2+) antiport); inhibition by diethylstilbestrol. The substrate kinetics revealed simple Michaelis Menten kinetics for ATP in the presence of 1 millimolar MgCl(2) with a K(m) value of 0.56 millimolar (0.38 millimolar for MgATP). AMP and c-AMP did not influence H(+) transport significantly. However, ADP was a potent competitive inhibitor with a K(i) value of 0.18 millimolar. The same inhibition type was found for membranes prepared from primary roots by the same procedure.
使用 pH 梯度依赖的未质子化中性红的减少，部分表征了来自玉米胚芽鞘微粒体膜中的阴离子敏感的 ATP 依赖性 H(+)转运。以下标准强烈表明观察到的 H(+)转运的液泡膜起源：严格依赖 Cl(-)；SO(4) (2-)和 NO(3) (-)抑制；对钒酸盐、钼酸盐和叠氮化物不敏感；可逆抑制 CaCl(2)（H(+)/Ca(2+)反向转运）；二乙基stilbestrol 抑制。在存在 1 毫摩尔 MgCl(2)的情况下，对于 ATP 的底物动力学显示出简单的米氏动力学，K(m)值为 0.56 毫摩尔（对于 MgATP 为 0.38 毫摩尔）。AMP 和 c-AMP 对 H(+)转运没有显著影响。然而，ADP 是一种有效的竞争性抑制剂，K(i)值为 0.18 毫摩尔。通过相同的程序从初生根制备的膜中也发现了相同的抑制类型。
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