Giunta C, De Bortoli M, Sanchini M, Stacchini A
Gen Pharmacol. 1985;16(3):183-8. doi: 10.1016/0306-3623(85)90066-7.
Ouabain and K-strophanthoside promote an enhancement of Na+/K+-ATPase activity in a range of cardioglycoside concentrations from 100 nM to 100 pM, with a maximum (+30%) between 10 and 4 nM. Binding experiments with [3H]ouabain show upward-curved Scatchard plots and evidence two intrinsic affinity constants for the ligand: (a) High-affinity constant: 350 nM (microsomes) and 15 nM (purified enzyme). (b) Low-affinity constant: 2100 nM (microsomes) and 890 nM (purified enzyme). The reaction velocity trend indicates that at ouabain concentrations higher than 20 nM but lower than the minimal inhibiting level, the enhanced reaction velocity is tending towards the control values.
哇巴因和毒毛旋花子苷 K 在 100 nM 至 100 pM 的一系列强心苷浓度范围内可促进 Na+/K+-ATP 酶活性增强，在 10 至 4 nM 之间达到最大值（+30%）。用 [3H]哇巴因进行的结合实验显示 Scatchard 图呈向上弯曲，并证明该配体有两个内在亲和常数：(a) 高亲和常数：350 nM（微粒体）和 15 nM（纯化酶）。(b) 低亲和常数：2100 nM（微粒体）和 890 nM（纯化酶）。反应速度趋势表明，在哇巴因浓度高于 20 nM 但低于最小抑制水平时，增强的反应速度趋向于对照值。
