Krishnan N, Albers R W
J Neurochem. 1980 Sep;35(3):753-5. doi: 10.1111/j.1471-4159.1980.tb03719.x.
We report on the interactions of Li+, a congener of K+ with the (Na+ + K+)-ATPase from E Electricus as measured by their effects on the rate of [3H]-ouabain binding to this enzyme. Like K+, Li+ slows ouabain binding under both Type I (Na+ + ATP) and Type II (P1) conditions, but with lower affinity. In contrast to K+, the Li+ inhibition curve is hyperbolic, suggesting interaction at an uncoupled site. Also differing from the complete inhibition by high K+, a residual ouabain-binding rate persists at high Li+. The interactions of Li+ and K+ are synergistic: the apparent K+ affinity increases 3 to 4-fold in presence of Li+. These results are consistent with the conclusion that Li+ interacts with only one of the two K+ sites and may be of interest in interpreting lithium pharmacology.
我们报告了锂离子（钾离子的同系物）与电鳗的（钠钾）-ATP酶之间的相互作用，通过它们对[3H]-哇巴因与该酶结合速率的影响来测定。与钾离子一样，锂离子在I型（钠+ATP）和II型（P1）条件下均会减慢哇巴因的结合，但亲和力较低。与钾离子不同，锂离子的抑制曲线是双曲线型的，表明其在一个未偶联的位点相互作用。同样与高钾离子的完全抑制不同，在高锂离子浓度下仍存在残余的哇巴因结合速率。锂离子和钾离子的相互作用是协同的：在锂离子存在的情况下，表观钾离子亲和力增加3至4倍。这些结果与锂离子仅与两个钾离子位点之一相互作用的结论一致，并且可能有助于解释锂药理学。
