Calpain Dissociates into Subunits in the Presence Ions
Calpain Dissociates into Subunits in the Presence Ions
复制标题
钙蛋白酶在离子存在下解离成亚基
DOI：
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发表时间：
1995
期刊：
影响因子：
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通讯作者：
Kazuo Suzuki
中科院分区：
文献类型：
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作者：
T. Yoshizawa;H. Sorimachi;S. Tomioka;S. Ishiura;Kazuo Suzuki
钙蛋白酶是一种钙依赖性半胱氨酸蛋白酶，由催化性80 K亚基和调节性30 K亚基组成。因此，人们认为钙蛋白酶作为二聚体发挥作用。在这里，我们已经发现，钙蛋白酶解离成亚基的存在下的Ca 2+所需的活性的表达和解离的80 K亚基是完全酶活性。此外，80 K亚基显示出与钙蛋白酶的活化形式相同的钙敏感性，但与原始对照钙蛋白酶不同。结果表明，钙蛋白酶的激活对应于在Ca ~（2+）存在下解离成亚基，并且钙蛋白酶在体内作为80 K亚基的单体起作用。
Calpain is a calcium dependent cysteine protease consisting of a catalytic 80K subunit and a regulatory 30K subunit. It has therefore been believed that calpain functions as a dimer. Here we have found that calpain dissociates into subunits in the presence of the Ca2+ required for the expression of activity and that the dissociated 80K subunit is enzymatically fully active. Moreover, the 80K subunit shows a calcium sensitivity identical to the activated form of calpain but not to the original control calpain. The results suggest that the activation of calpain corresponds to the dissociation into subunits in the presence of Ca2+ and that calpain functions as a monomer of the 80K subunit in vivo.