Direct metal analyses of Mn2+-dependent and -independent protein phosphatase 2A from human erythrocytes detect zinc and iron only in the Mn2+-independent one
Direct metal analyses of Mn2+-dependent and -independent protein phosphatase 2A from human erythrocytes detect zinc and iron only in the Mn2+-independent one
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DOI：
10.1016/s0014-5793(99)00256-2
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发表时间：
1999-03-19
期刊：
影响因子：
3.5
通讯作者：
Takeda, M
中科院分区：
文献类型：
--
作者：
Nishito, Y;Usui, H;Takeda, M
从人红细胞胞质中纯化出一种Mn ~（2+）依赖性蛋白磷酸酶2A，它由一个34 kDa的催化C'亚基和一个63 kDa的调节A'亚基组成，C'和A'产生的V_8和木瓜蛋白酶肽图分别与人红细胞胞质中Mn ~（2+）非依赖性常规蛋白磷酸酶的34 kDa的催化C和63 kDa的调节A亚基的肽图相同。C 'A和CA'的重构揭示了金属依赖性存在于C'而不是A'。在CA中，每摩尔酶用原子吸收分光光度法检测到0.87 +/- 0.12 mol锌和0.35 +/- 0.18 mol铁，但未检测到锰、镁和钴。在C 'A'中未检测到这些金属。C'与ZnCl 2和FeCl 2（而不是FeCl 3）预孵育，协同刺激了Mn 2+非依赖性蛋白磷酸酶活性。蛋白磷酸酶活性的C不受相同的锌和/或铁处理。这些结果表明C是一种Zn ~（2+）和Fe ~（2+）金属酶，C'是脱辅基酶。(C)1999年欧洲生物化学学会联合会。
A Mn2+-dependent protein phosphatase 2A which is composed of a 34 kDa catalytic C' subunit and a 63 kDa regulatory A' subunit, was purified from human erythrocyte cytosol, C' and A' produced V8- and papain-peptide maps identical to those of the 34 kDa catalytic C and the 63 kDa regulatory A subunits of the Mn2+-independent conventional protein phosphatase in human erythrocyte cytosol, respectively. Reconstitution of C'A and CA' revealed that the metal dependency resided in C' and not in A'. In CA, 0.87 +/- 0.12 mol zinc and 0.35 +/- 0.18 mol iron per mol enzyme were detected by atomic absorption spectrophotometry, but manganese, magnesium and cobalt mere not detected. None of these metals was detected in C'A'. Pre-incubation of C' with ZnCl2 and FeCl2, but not FeCl3, synergistically stimulated the Mn2+-independent protein phosphatase activity. The protein phosphatase activity of C was unaffected by the same zinc and/or iron treatment. These results suggest that C is a Zn2+- and Fe2+-metalloenzyme and that C' is the apoenzyme. (C) 1999 Federation of European Biochemical Societies.