钒酸盐对人红细胞膜Ca2 + -ATP酶的抑制作用。
Vanadate inhibition of the Ca2+-ATPase from human red cell membranes.
作者信息
Barrabin H, Garrahan P J, Rega A F
出版信息
Biochim Biophys Acta. 1980 Aug 14;600(3):796-804. doi: 10.1016/0005-2736(80)90482-4.
(1) VO3(-) combines with high affinity to the Ca2+-ATPase and fully inhibits Ca2+-ATPase and Ca2+-phosphatase activities. Inhibition is associated with a parallel decrease in the steady-state of the Ca2+-dependent phosphoenzyme. (2) VO3(-) blocks hydrolysis of ATP at the catalytic site. The sites for VO3(-) also exhibit negative interactions in affinity with the regulatory sites for ATP of the Ca2+-ATPase. (3) The sites for VO39-) show positive interaactions in affinity with sites for Mg2+ and K+. This accounts for the dependence on Mg2+ and K+ of the inhibition by VO3(-). Although, with less effectiveness, Na2+ and K+ substitutes for K+ whereas Li+ does not. The apparent affinites for Mg24 and K+ for inhibiton by VO3(-) seem to be less than those for activation of the Ca2+-ATPase. (4) Inhibition by VO3(-) is independent of Ca2+ at concentrations up to 50 microM. Higher concentrations of Ca2+ lead to a progressive release of the inhibitiory effect of VO3(-).
(1) VO₃⁻与Ca²⁺-ATP酶具有高亲和力结合，并完全抑制Ca²⁺-ATP酶和Ca²⁺-磷酸酶活性。抑制作用与Ca²⁺依赖性磷酸酶的稳态平行下降有关。(2) VO₃⁻在催化位点阻断ATP的水解。VO₃⁻的结合位点在亲和力方面也与Ca²⁺-ATP酶的ATP调节位点表现出负相互作用。(3) VO₃⁻的结合位点在亲和力方面与Mg²⁺和K⁺的结合位点表现出正相互作用。这解释了VO₃⁻抑制作用对Mg²⁺和K⁺的依赖性。虽然Na⁺和K⁺可部分替代K⁺，但Li⁺不能。VO₃⁻抑制作用对Mg²⁺和K⁺的表观亲和力似乎低于Ca²⁺-ATP酶激活时对它们的亲和力。(4) 在浓度高达50微摩尔时，VO₃⁻的抑制作用不依赖于Ca²⁺。更高浓度的Ca²⁺会导致VO₃⁻抑制作用逐渐解除。
Zotero 插件