Londesborough J, Lukkari T M
J Cyclic Nucleotide Res. 1979;5(2):145-51.
The stability constants of complexes of 3', 5'-cyclic AMP with Mg2+, Ca2+, Mn2+, Ni2+ and Co2+ were estimated at 30 degrees C in solutions of ionic strength about 0.15 containing about 130 mM K+ or tetramethylammonium ions. Values between 13 and 22 M-1 were obtained, indicating that only about 2% of cyclic AMP is present as metal complexes in vivo, but that at commonly used in vitro concentrations of 10 mM bivalent metal ions, 10--20% of cyclic AMP is present as metal complexes. The possible significance of these metal complexes, for example as competitive inhibitors, is discussed.
在含有约130 mM K⁺或四甲基铵离子、离子强度约为0.15的溶液中，于30℃测定了3',5'-环磷酸腺苷与Mg²⁺、Ca²⁺、Mn²⁺、Ni²⁺和Co²⁺形成的配合物的稳定常数。得到的值在13至22 M⁻¹之间，这表明在体内只有约2%的环磷酸腺苷以金属配合物的形式存在，但在体外常用的10 mM二价金属离子浓度下，10% - 20%的环磷酸腺苷以金属配合物的形式存在。文中讨论了这些金属配合物可能具有的意义，例如作为竞争性抑制剂的意义。
