Nuclear magnetic resonance spectra of adenosine di- and triphosphate. II. Effect of complexing with divalent metal ions.
Nuclear magnetic resonance spectra of adenosine di- and triphosphate. II. Effect of complexing with divalent metal ions.
复制标题
二磷酸腺苷和三磷酸腺苷的核磁共振谱。
DOI：
--
复制
发表时间：
1962
影响因子：
4.8
通讯作者：
T. R. Hughes
中科院分区：
文献类型：
--
作者：
M. Cohn;T. R. Hughes
所有涉及二磷酸和三磷酸腺苷的酶促反应都需要二价金属离子，这一点已经得到了很好的证实，但金属离子的作用还不清楚。在某些激酶反应（1，2）中，动力学证据表明三磷酸腺苷的金属络合物是酶促反应中的真正底物。本研究的目的是获得有关腺苷二磷酸和三磷酸的结构变化所造成的各种二价金属离子的相互作用的信息。这样的信息可能会揭示由金属离子诱导的核苷酸中特定键的反应性的变化，并且肯定会对这些化合物的酶-底物复合物的任何拟议结构施加限制。在先前的论文（3）中，已经表明，可以在0.1 M的核苷酸溶液上测量二磷酸腺苷和三磷酸腺苷的磷核的核磁共振峰的化学位移。在本研究中应用了相同的技术来观察金属离子存在下磷磁共振光谱化学位移的变化，以提供所形成复合物性质的直接证据。利用高分辨技术，可以将核苷酸中质子核磁共振谱的化学位移与金属配合物中的位移进行比较，以确定金属离子与腺嘌呤环的相互作用。测量扩展到包括顺磁性离子，如Mn ++和Cu++在低浓度的顺序为10 -4至10 -5 M的磷和质子的吸收线的宽度上的效果。这样的光谱揭示了与特定磷核和质子的优先相互作用，从而确定了所形成的络合物的性质。met.al
The requirement of a divalent metal ion for all enzymatic reactions involving adenosine diand triphosphate is well established, but the role of the metal ion is not clearly understood. In some kinase reactions (1, 2) kinetic evidence has been presented that the metal complex of adenosine triphosphate is the true substrate in the enzymatic reaction. The present study was undertaken to obtain information concerning changes in the structure of adenosine diand triphosphate caused by interactions with various divalent metal ions. Such information might shed some light on the changes in the reactivity of specific bonds in the nucleotides induced by the met’al ions and would certainly impose limitations on any proposed structure of an enzyme-substrate complex for these compounds. In a previous paper (3), it was shown that chemical shifts of the nuclear magnetic resonance peaks of the phosphorus nuclei of adenosine diand triphosphate could be measured on 0.1 M solutions of the nucleotides. The same techniques have been applied in the present investigation to observe the changes in the chemical shifts of the phosphorus magnetic resonance spectra in the presence of metal ions to give direct evidence of the nature of the complexes formed. With the use of high resolution technique, the chemical shifts of the proton magnetic resonance spectra in the nucleotides could be compared with the shifts in the metal complexes to determine the interaction of the metal ion with the adenine ring. The measurements were extended to include the effect of paramagnetic ions such as Mn ++ and Cu++ at low concentrations of the order of 1O-4 to 1O-5 M on the width of the absorption lines of both phosphorus and protons. Such spectra revealed preferential interactions with particular phosphorus nuclei and protons, thus specifying the nature of the met.al complexes formed.