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首页> 外文期刊>Dalton transactions: An international journal of inorganic chemistry >Dinuclear Zn~(2+) complexes in the hydrolysis of the phosphodiestr linkage in a diribonucleoside monophosphate diester
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Dinuclear Zn~(2+) complexes in the hydrolysis of the phosphodiestr linkage in a diribonucleoside monophosphate diester

机译:核糖核苷单磷酸二酯中磷酸二酯键水解中的双核Zn〜(2+)配合物

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摘要

Dizinc complexes that were formed from 2:1 mixtures of Zn(NO_3)_2 and dinucleating ligand TPHP(1),TPmX(2) or TPpX(3) in aqueous solutions efficiently hydrolyzed diribonucleoside monophsphate diesters (NpN) under mild conditions.The dinucleating ligand affected the structure of the aquo-hydroxo-dizinc core,resultignin different of (Zn~(2+))_2-1 was sigmoidal,whereas those of (Zn~(2+)_-2 and (Zn~(2+))_2-3 were bell-shaped.The pH titraton study indicated that (Zn~(2+))-1 disscaites only one aquo proton (up to pH 12),whreas (Zn~(2+))-2 dissociates three aquo protons (up to pH 10.7).The observed differences in the pH-rate profile are attributable to the various distributions of the monohydroxo-dizinc species,which are responsible for NpN cleavage.As compared to that using (Zn~(2+))-1,the NpN cleavage usign (Zn~(2+))-2 showed a greatr rate constant,with a higher prduct ratio of 3'-NMP/2'-NMP.The saturation behaviors of the rate,with regard to the concentration of NpN,were analyzed by Michaelis-Menten typekinetics.Although the binding of ((Zn~(2+))-2 to ApA was weaker than that of (Zn~(2+))-1,(Zn~(2+))-2 showed a greeater k_(cat) value than ((Zn~(2+))-1,resultign in higher ApA cleavage activity of the former.
机译:由Zn(NO_3)_2和成核配体TPHP(1),TPmX(2)或TPpX(3)的2:1混合物在水溶液中形成的Dizinc络合物在温和条件下有效地水解了双核糖核苷单磷酸二酯(NpN)。配体影响水-羟基-二嗪核心的结构,(Zn〜(2 +))_ 2-1的结果木质素呈S形,而(Zn〜(2 +)_- 2和(Zn〜(2+ ))_ 2-3为钟形。pH滴定法研究表明(Zn〜(2 +))-1仅分解一个水生质子(pH最高至12),而(Zn〜(2 +))-2分解3个质子(最高pH 10.7)。观察到的pH速率差异归因于一元羟基二嗪物种的各种分布,这些分布负责NpN的裂解。与使用(Zn〜(2+ ))-1时,NpN裂解的USign(Zn〜(2 +))-2表现出较大的速率常数,具有较高的3'-NMP / 2'-NMP生成物比率。迈克尔分析了NpN的浓度尽管((Zn〜(2 +))-2与ApA的结合弱于(Zn〜(2 +))-1,(Zn〜(2 +))-2的结合力很弱。比((Zn〜(2 +))-1)的k_(cat)值高,导致前者的ApA裂解活性更高。

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