Krstić Danijela, Colović Mirjana, Bosnjaković-Pavlović Nada, Spasojević-De Bire Anne, Vasić Vesna
Institute of Medicinal Chemistry, University School of Medicine, Visegradska 26, 11 000 Belgrade, Serbia.
Gen Physiol Biophys. 2009 Sep;28(3):302-8. doi: 10.4149/gpb_2009_03_302.
The in vitro influence of decameric vanadate species on Na+/K+-ATPase, plasma membrane Ca2+-ATPase (PMCA)-calcium pump and ecto-ATPase activity, using rat synaptic plasma membrane (SPM) as model system was investigated, whereas the commercial porcine cerebral cortex Na+/K+-ATPase served as a reference. The thermal behaviour of the synthesized decavanadate (V10) has been studied by differential scanning calorimetry and thermogravimetric analysis, while the type of polyvanadate anion was identified using the IR spectroscopy. The concentration-dependent responses to V10 of all enzymes were obtained. The half-maximum inhibitory concentration (IC50) of the enzyme activity was achieved at (4.74 +/- 1.15) x 10(-7) mol/l for SPM Na+/K+-ATPase, (1.30 +/- 0.10) x 10(-6) mol/l for commercial Na+/K+-ATPase and (3.13 +/- 1.70) x 10(-8) mol/l for Ca2+-ATPase, while ecto-ATPase is significantly less sensitive toward V10 (IC50 = (1.05 +/- 0.10) x 10(-4) mol/l) than investigated P-type ATPases. Kinetic analysis showed that V10 inhibited Na+/K+-ATPase by reducing the maximum enzymatic velocity and apparent affinity for ATP (increasing K(m) value), implying a mixed mode of interaction between V10 and P-type ATPases.
以大鼠突触质膜（SPM）为模型系统，研究了十聚钒酸盐对Na⁺/K⁺-ATP酶、质膜Ca²⁺-ATP酶（PMCA）-钙泵和胞外ATP酶活性的体外影响，同时以市售猪脑皮质Na⁺/K⁺-ATP酶作为对照。采用差示扫描量热法和热重分析法研究了合成的十钒酸盐（V10）的热行为，并用红外光谱法鉴定了多钒酸根阴离子的类型。获得了所有酶对V10的浓度依赖性反应。对于SPM的Na⁺/K⁺-ATP酶，酶活性的半数抑制浓度（IC50）为（4.74±1.15）×10⁻⁷mol/L；对于市售Na⁺/K⁺-ATP酶，IC50为（1.30±0.10）×10⁻⁶mol/L；对于Ca²⁺-ATP酶，IC50为（3.13±1.70）×10⁻⁸mol/L，而胞外ATP酶对V10的敏感性（IC50 =（1.05±0.10）×10⁻⁴mol/L）明显低于所研究的P型ATP酶。动力学分析表明，V10通过降低最大酶促速度和对ATP的表观亲和力（增加K(m)值）来抑制Na⁺/K⁺-ATP酶，这意味着V10与P型ATP酶之间存在混合相互作用模式。
