Benaim G, Moreno S N, Hutchinson G, Cervino V, Hermoso T, Romero P J, Ruiz F, de Souza W, Docampo R
Department of Veterinary Pathobiology, University of Illinois at Urbana-Champaign 61801.
Biochem J. 1995 Feb 15;306 ( Pt 1)(Pt 1):299-303. doi: 10.1042/bj3060299.
Despite previous reports [McLaughlin (1985) Mol. Biochem. Parasitol. 15, 189-201; Ghosh, Ray, Sarkar and Bhaduri (1990) J. Biol. Chem. 265, 11345-11351; Mazumder, Mukherjee, Ghosh, Ray and Bhaduri (1992) J. Biol. Chem. 267, 18440-18446] suggesting that the plasma-membrane Ca(2+)-ATPases of different trypanosomatids differ from the Ca2+ pumps present in mammalian cells, Trypanosoma cruzi plasma-membrane Ca(2+)-ATPase shares several characteristics with the Ca2+ pumps present in other systems. This enzyme could be partially purified from epimastigote plasma-membrane vesicles using calmodulin-agarose affinity chromatography. The activity of the partially purified enzyme was stimulated by T. cruzi or bovine brain calmodulin. In addition, the enzyme cross-reacted with antiserum and monoclonal antibody 5F10 raised against human red-blood-cell Ca(2+)-ATPase, has a molecular mass of 140 kDa and forms Ca(2+)-dependent hydroxylamine-sensitive phosphorylated intermediates. These results, together with its high sensitivity to vanadate, indicate that this enzyme belongs to the P-type class of ionic pumps.
尽管先前有报道[麦克劳克林（1985年），《分子生物化学寄生虫学》第15卷，第189 - 201页；戈什、雷、萨卡尔和巴杜里（1990年），《生物化学杂志》第265卷，第11345 - 11351页；马宗德、慕克吉、戈什、雷和巴杜里（1992年），《生物化学杂志》第267卷，第18440 - 18446页]表明不同锥虫的质膜Ca(2 +)-ATP酶与哺乳动物细胞中的Ca2 +泵不同，但克氏锥虫质膜Ca(2 +)-ATP酶与其他系统中的Ca2 +泵具有一些共同特征。该酶可以通过钙调蛋白 - 琼脂糖亲和色谱从副鞭毛体质膜囊泡中部分纯化出来。部分纯化酶的活性受到克氏锥虫或牛脑钙调蛋白的刺激。此外，该酶与针对人红细胞Ca(2 +)-ATP酶产生的抗血清和单克隆抗体5F10发生交叉反应，分子量为140 kDa，并形成Ca(2 +)依赖性的对羟胺敏感的磷酸化中间体。这些结果，连同其对钒酸盐的高敏感性，表明该酶属于P型离子泵。
