EFFECT OF BIVALENT METAL IONS ON HYDROLYSIS OF ADENOSINE DI- AND TRIPHOSPHATE
EFFECT OF BIVALENT METAL IONS ON HYDROLYSIS OF ADENOSINE DI- AND TRIPHOSPHATE
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DOI：
10.1021/bi00902a030
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发表时间：
1963-01-01
期刊：
影响因子：
2.9
通讯作者：
LOWENSTEIN, JM
中科院分区：
文献类型：
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作者：
TETAS, M;LOWENSTEIN, JM
许多二价金属离子在 pH 5 和 9 时催化三磷酸腺苷 (ATP) 的水解。在 Cui+ 和 Zn,+ 离子存在下，ATP 的水解速率在 pH 5 时达到最佳值。与不存在二价金属离子时的水解速率相比，这些离子在 pH 5 时分别使 ATP 的水解速率增加约 60 倍和 12 倍。二磷酸腺苷 (ADP) 的水解速率在 pH 5 时几乎不受许多二价金属离子的影响，但在 pH 9 时被大多数二价金属离子加速。在 pH 9 时，Cui+ 和 Zn1+ 离子分别使 ADP 的水解速率增加约 9 倍和 5 倍。Mn2+ 离子对 ATP 和 ADP 水解的影响与 Cu2+ 和 Zn2+ 明显不同离子。在 ATP 水解过程中，在 pH 5 时，在二价金属离子存在下形成的无机焦磷酸盐的量可以忽略不计。在 pH 9 时，它的重要性次要，除非存在 Ca2+ 离子，在这种情况下，形成的正磷酸盐和焦磷酸盐中约三分之一是焦磷酸盐。据认为，ADP 和 ATP 水解的金属离子特异性是由不同二价金属离子形成的不同类型螯合物以及与不同二价金属离子作用的不同反应机制的结果。二价金属催化磷酸盐从三磷酸腺苷 (ATP) 到各种受体（如正磷酸盐、乙酸盐、甘氨酸和/3-丙氨酸）的非酶转移（Lowenstein，1958a， b；洛文斯坦和沙茨，1961）。当正磷酸盐是磷酸盐受体时，反应产物是焦磷酸盐，最有效的二价金属离子是 Ca、Sr 和 Ba，随后按有效性降序排列是 Mn、Cd 和 Zn。该反应的最适 pH 值为 9.0 (Lowenstein, 1958a, 1960)。当在羟胺存在下使用乙酸盐作为受体时，反应产物是乙酰异羟肟酸盐，并且最有效的二价金属离子按有效性降序排列为Be、Ni、Co、Zn和Mn。该反应的最适 pH 值为 5.2（Lowenstein 和 Schatz，1961）。类似地，对于甘氨酸，反应产物是甘氨酸异羟肟酸，最有效的二价金属离子按有效性降序排列为Be、Zn、Mn、Ca 和Cd。该反应的最适pH为5.0。关于 Mg、Ca 和 Ba 离子对 ATP 和二磷酸腺苷 (ADP) 水解影响的各种研究已有报道 (Lohmann, 1932; Spicer, 1952; Hock 和 Huber, 1956; Nanninga, 1957; Liébecq 和 Jaequemotte-Louis, 1958a, b; Liébecq, 1959; Blum 和 Felauer，1959；Lipkin 等人，1959）。 Liébecq 和 Jacquemotte-Louis (1958a) 比较了 pH 8.5 时十种不同二价金属离子的影响。特别令人感兴趣的是一份涉及
Many bivalentmetal ions catalyze the hydrolysis of adenosine triphosphate (ATP) at pH 5 and 9. In the presence of Cui+ and Zn,+ ions, the rate of hydrolysis of ATP passes through an optimum at pH 5. These ions increase the rate ofhydrolysis of ATP about 60-fold and 12-fold, respectively, at pH 5, compared to the rate of hydrolysis in the absence of bivalent metal ions. The rate of hydrolysis of adenosine diphosphate (ADP) is scarcely affected by many bivalent metal ions at pH 5 but is accelerated by most bivalent metal ionsat pH 9. Cui+ and Zn1+ ions increase the rate of hydrolysis of ADP about 9-fold and 5-fold, respectively, at pH 9. The effect of Mn2+ ions on both ATP and ADP hydrolysis is markedly different from that of Cu2+ and Zn2+ ions. In the hydrolysis of ATP, the amount of inorganic pyrophosphate formed in the presence of bivalent metal ionsis negligible at pH 5. It is of minor importance at pH 9, except in the presence of Ca2+ ions, in which case about one third of the orthophosphate plus pyrophosphate formed is pyrophosphate. It is proposed that the metal ion speci-ficities of ADP and ATP hydrolysis are the consequence of different types of chelates which are formed with different bivalent metal ions and of different reaction mechanisms which operate with different bivalent metal ions.Bivalent metals catalyze the nonenzymatic transfer of phosphate from adenosine triphosphate (ATP) to various acceptors such as orthophosphate, acetate, glycine, and/3-alanine (Lowenstein, 1958a, b; Lowen-stein and Schatz, 1961). When orthophosphate is the phosphate acceptor, the product of the reaction is pyrophosphate and the most effective bivalent metal ions are Ca, Sr, and Ba, followed in decreasing order of effectiveness by Mn, Cd, and Zn. The pH optimum of the reaction is 9.0 (Lowenstein, 1958a, 1960). When acetate is used as acceptor in the presence of hydroxy lamine, the product of the reaction is aceto-hydroxamate and the most effective bivalent metal ions are, in decreasing order of effectiveness, Be, Ni, Co, Zn, and Mn. The pH optimum of the reaction is 5.2 (Lowenstein and Schatz, 1961). Similarly, with gly-cine, theproduct of the reaction is glycinehydroxamate and the most effective bivalent metal ions are, in decreasing order of effectiveness, Be, Zn, Mn, Ca, and Cd. The pH optimum of this reaction is 5.0. Various studies of the effect of Mg, Ca, and Ba ions on the hydrolysis of ATP and adenosine diphosphate (ADP) have been reported (Lohmann, 1932; Spicer, 1952; Hock and Huber, 1956; Nanninga, 1957; Liébecq and Jaequemotte-Louis, 1958a, b; Liébecq, 1959; Blum and Felauer, 1959; Lipkin et al., 1959). The effect of ten different bivalent metal ions at pH 8.5 was com-pared by Liébecq and Jacquemotte-Louis (1958a). Of particular interest was a report which dealt with the