溶血产物对钙抑制人红细胞（Na⁺ + K⁺）-ATP酶的影响。

Effect of hemolysate on calcium inhibition of the (Na+ + K+)-ATPase of human red blood cells.

作者信息

Yingst D R, Marcovitz M J

出版信息

Biochem Biophys Res Commun. 1983 Mar 29;111(3):970-9. doi: 10.1016/0006-291x(83)91395-5.

Abstract

The sensitivity of the (Na+ + K+)-ATPase in human red cell membranes to inhibition by Ca2+ is markedly increased by the addition of diluted cytoplasm from hemolyzed human red blood cells. The concentration of Ca2+ causing 50% inhibition of the (Na+ + K+)-ATPase is shifted from greater than 50 microM free Ca2+ in the absence of hemolysate to less than 10 microM free Ca2+ when hemolysate diluted 1:60 compared to in vivo concentrations is added to the assay mixture. Boiling the hemolysate destroys its ability to increase the sensitivity of the (Na+ + K+)-ATPase to Ca2+. Proteins extracted from the membrane in the presence of EDTA and concentrated on an Amicon PM 30 membrane increased the sensitivity of the (Na+ + K+)-ATPase to Ca2+ in a dose-dependent fashion, causing over 80% inhibition of the (Na+ + K+)-ATPase at 10 microM free Ca2+ at the highest concentration of the extract tested. The active factor in this membrane extract is Ca2+-dependent, because it had no effect on the (Na+ + K+)-ATPase in the absence of Ca2+. Trypsin digestion prior to the assay destroyed the ability of this protein extract to increase the sensitivity of the (Na+ + K+)-ATPase to Ca2+.

摘要

通过添加来自溶血人红细胞的稀释细胞质，人红细胞膜中（Na⁺ + K⁺）-ATP酶对Ca²⁺抑制作用的敏感性显著增加。导致（Na⁺ + K⁺）-ATP酶50%抑制的Ca²⁺浓度，在无溶血产物时大于50微摩尔游离Ca²⁺，而当与体内浓度相比稀释1:60的溶血产物添加到测定混合物中时，则低于10微摩尔游离Ca²⁺。煮沸溶血产物会破坏其增加（Na⁺ + K⁺）-ATP酶对Ca²⁺敏感性的能力。在EDTA存在下从膜中提取并在Amicon PM 30膜上浓缩的蛋白质，以剂量依赖方式增加了（Na⁺ + K⁺）-ATP酶对Ca²⁺的敏感性，在测试提取物的最高浓度下，在10微摩尔游离Ca²⁺时导致（Na⁺ + K⁺）-ATP酶超过80%的抑制。这种膜提取物中的活性因子依赖于Ca²⁺，因为在无Ca²⁺时它对（Na⁺ + K⁺）-ATP酶没有影响。在测定前用胰蛋白酶消化会破坏这种蛋白质提取物增加（Na⁺ + K⁺）-ATP酶对Ca²⁺敏感性的能力。