Kinetic characterization of a membrane-specific ATPase from rat osseous plate and its possible significance on endochondral ossification
Kinetic characterization of a membrane-specific ATPase from rat osseous plate and its possible significance on endochondral ossification
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DOI：
10.1016/s0005-2736(97)00174-0
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发表时间：
1998-01-05
影响因子：
3.4
通讯作者：
Leone, FA
中科院分区：
文献类型：
--
作者：
Pizauro, JM;Demenis, MA;Leone, FA
用磷脂酰肌醇特异性磷脂酶C处理大鼠骨板膜，释放高达90-95%的碱性磷酸酶，但特异性ATP酶活性（最适pH = 7.5）仍与膜结合。在不存在镁或钙离子的情况下，ATP酶对ATP的水解可以忽略不计。然而，在镁离子和钙离子的毫摩尔浓度下，膜特异性ATP酶活性增加到约560-600 U/mg，表现出两类ATP水解位点和位点-位点相互作用。GTP、UTP、ITP和CTP也被膜特异性ATP酶水解。寡霉素、哇巴因、巴弗洛霉素A（1）、毒胡萝卜素、奥美拉唑、依他尼酸和EDTA对膜特异性ATP酶活性有轻微影响，而钒酸盐产生18%的抑制。膜特异性ATP酶活性对茶碱不敏感，但左旋咪唑可抑制40%。这些数据表明，存在于骨板膜中的膜特异性ATP酶活性和碱性磷酸酶是不同的蛋白质。(C)1998年Elsevier Science B.V.
Treatment with phosphatidylinositol-specific phospholipase C of rat osseous plate membranes released up to 90-95% of alkaline phosphatase, but a specific ATPase activity (optimum pH = 7.5) remained bound to the membrane. The hydrolysis of ATP by this ATPase was negligible in the absence of magnesium or calcium ions. However, at millimolar concentrations of magnesium and calcium ions, the membrane-specific ATPase activity increased to about 560-600 U/mg, exhibiting two classes of ATP-hydrolysing sites, and site-site interactions. GTP, UTP, ITP, and CTP were also hydrolyzed by the membrane-specific ATPase. Oligomycin, ouabain, bafilomycin A(1), thapsigargin, omeprazole, ethacrynic acid and EDTA slightly affected membrane-specific ATPase activity while vanadate produced a 18% inhibition. The membrane-specific ATPase activity was insensitive to theophylline, but was inhibited 40% by levamisole. These data suggested that the membrane-specific ATPase activity present in osseous plate membranes, and alkaline phosphatase, were different proteins. (C) 1998 Elsevier Science B.V.