Joiner C H, Lauf P K
J Membr Biol. 1975 Apr 23;21(1-2):99-112. doi: 10.1007/BF01941064.
Binding of 3H-ouabain was studied in high potassium (HK) and low potassium (LK) sheep red cells. In particular, we investigated the effect of anti-L, an antibody raised in HK sheep against L-positive LK sheep red cells, on 3H-oubain binding and its relation to K+ -pump flux inhibition in LK cells. HK cells were found to have about twice as many 3H-ouabain binding sites and a higher association rate for 3H-ouabain than homozygous LL-type LK cells. The number of 3H-ouabain molecules bound to heterozygous LM-type LK cells is lower than that on LL cells, but the rate of ouabain binding is between that of HK and LL red cells. A close correlation was observed between the rates of 3H-oubain binding and fraction K+-pump inhibition. Exposure of LM and LL cells to anti-L did not affect the number of 3H-ouabain molecules bound at saturation, but increased the rates of glycoside binding and K+ -pump inhibition proportionately, so that for LK cells in the presence of anti-L, the rates of the two processes approximate those of HK cells. These data exclude the possibility that anti-L generates entirely new pump sites in LK sheep cells, but suggest that the antibody increases the affinity of the existing -a+ -K+ pumps for the glycoside.
在高钾（HK）和低钾（LK）绵羊红细胞中研究了³H-哇巴因的结合情况。特别地，我们研究了在HK绵羊中产生的针对L阳性LK绵羊红细胞的抗-L抗体对³H-哇巴因结合的影响及其与LK细胞中K⁺-泵通量抑制的关系。发现HK细胞的³H-哇巴因结合位点数量约为纯合LL型LK细胞的两倍，且³H-哇巴因的结合速率更高。与杂合LM型LK细胞结合的³H-哇巴因分子数量低于LL细胞，但哇巴因结合速率介于HK和LL红细胞之间。观察到³H-哇巴因结合速率与K⁺-泵抑制分数之间存在密切相关性。将LM和LL细胞暴露于抗-L不会影响饱和时结合的³H-哇巴因分子数量，但会相应地增加糖苷结合速率和K⁺-泵抑制，因此对于存在抗-L的LK细胞，这两个过程的速率接近HK细胞。这些数据排除了抗-L在LK绵羊细胞中产生全新泵位点的可能性，但表明该抗体增加了现有Na⁺-K⁺泵对糖苷的亲和力。
