The two gates, never both openNa⁺K⁺ATP and its phosphateThe outside of the cell is above the membrane, the cytoplasm below (ruler: 1 tick = 1 nm). Every cycle the pump takes 3 Na⁺ from inside, spends one ATP to lock them in, opens outward and lets them go, takes 2 K⁺ from outside, drops the phosphate, and opens inward again: one net charge leaves per cycle. Two leak channels let ions run back down their gradients at a rate set by the gradient; with the pump running the two balance. Click to add ouabain, the plant toxin that jams the pump in its outward-open state: the leaks win and the gradients fade. A real pump turns over about 100 times a second; shown 600× slower, with a dozen ions standing for millions.
3 : 2Na⁺ 出 : K⁺ 进 / 每个 ATPNa⁺ out : K⁺ in per ATP~100 /s37 °C 周转率turnover at 37 °C145 / 12 mMNa⁺ 胞外 / 胞内Na⁺ outside / inside4 / 140 mMK⁺ 胞外 / 胞内K⁺ outside / inside~20–40%静息时细胞 ATP 用在这里（神经元更多）of a resting cell's ATP spent here (more in neurons)1957Skou 发现（1997 诺奖）discovered by Skou (Nobel 1997)