Spectral properties of Co(II)- and Ni(II)-activated rabbit muscle pyruvate kinase.
Spectral properties of Co(II)- and Ni(II)-activated rabbit muscle pyruvate kinase.
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Co(II) 和 Ni(II) 激活的兔肌肉丙酮酸激酶的光谱特性。
DOI：
10.1016/s0021-9258(19)41143-5
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发表时间：
1975
期刊：
影响因子：
--
通讯作者：
R. Davis
中科院分区：
文献类型：
--
作者：
C. Kwan;K. Erhard;R. Davis
研究了Co（Ⅱ）、Ni（Ⅱ）、Mg（Ⅱ）和Mn（Ⅱ）激活兔肌肉丙酮酸激酶的化学计量、动力学和光学性质。通过进行圆二色性滴定，发现与酶结合的金属的化学计量为Co（II）和Ni（II）的每四聚体酶4个金属离子。Cu（II）和Fe（II）不活泼。Ca（II）和Zn（II）不活化，并且相对于所有活性阳离子是抑制性的。对于所有活化金属，最佳速度的温度依赖性是相似的。的pH值速率曲线表明，有两类金属离子的酶激活。Mg（II）和Mn（II）彼此非常相似，而Co（II）和Ni（II）与它们不同但彼此相似。吸收，自然，和磁性CD在可见光区被用来探测环境中的激活二价阳离子在镍（II）和钴（II）激活丙酮酸激酶和它们的复合物与底物和抑制剂。
Stoichiometry, kinetics, and optical properties of rabbit muscle pyruvate kinase activated with Co(II), Ni(II), Mg(II), and Mn(II) were studied. The stoichiometry of metal binding to enzyme was found to be 4 metal ions per tetrameric enzyme for Co(II) and Ni(II) by carrying out circular dichroic titrations. Cu(II) and Fe(II) were inactive. Ca(II) and Zn(II) were not activating, and were inhibitory with respect to all of the active cations. The temperature dependence of the optimal velocity is similar for all activating metals. The pH rate profiles suggest that there are two classes of enzyme activation by metal ions. Mg(II) and Mn(II) are quite similar to each other while Co(II) and Ni(II) are different from them but similar to each other. Absorption, natural, and magnetic CD in the visible region were used to probe the environment of the activating divalent cation in Ni(II)- and Co(II)-activated pyruvate kinase and their complexes with substrates and inhibitors...