经常建议酶催化的磷酰基转移反应通过从其溶液对应物改变的过渡态进行。然而,先前对大肠杆菌碱性磷酸酶 (AP) 的研究表明,这种酶通过松散的解离过渡态催化磷酸单酯的水解,类似于溶液中的过渡态。尽管在溶液中磷酸二酯水解具有更紧密、更缔合的过渡态,但 AP 还表现出催化混杂,具有低水平的磷酸二酯酶活性。因为 AP 在进化上针对磷酸单酯水解进行了优化,所以活性位点环境可能会改变二酯水解的过渡状态,使其与传入和传出基团的键合更松散。为了测试这种可能性,我们已经测量了一系列取代的甲基苯基磷酸二酯的非酶促和 AP 催化的反应速率。beta(lg) 的值和其他数据表明 AP 催化的磷酸二酯水解的过渡态与溶液中的过渡态无法区分。AP 通过识别和稳定类似于水溶液中的过渡态来催化磷酰基转移反应,而不是改变过渡态结构。因此,AP 活性位点能够识别不同的过渡状态,这一特性有助于混杂活动的进化优化。beta(lg) 的值和其他数据表明
Reactivity of Phosphate Diesters Doubly Coordinated to a Dinuclear Cobalt(III) Complex: Dependence of the Reactivity on the Basicity of the Leaving Group
作者:Nicholas H. Williams、William Cheung、Jik Chin
DOI:10.1021/ja980660s
日期:1998.8.1
Reactivities of dialkyl phosphatescoordinated to the dinuclear Co(III) complex (1,2-propylene phosphate (3); dimethyl phosphate (4)) were also investigated. Hydrolysis of the phosphatediesters in 1a to 1d takes place by intramolecular oxide attack on the bridging phosphate while hydrolysis of 3 principally takes place by intermolecular hydroxide attack on the bridging phosphate. The diester in 2a cleaves by
Metal Ion Dependent Site Selective Cleavage of P–O–S Linkage in the Methanolysis of Phenyl Phosphatosulfate
作者:Toshio Eiki、Waichiro Tagaki
DOI:10.1246/bcsj.64.1235
日期:1991.4
various metalions on the methanolysis of phenyl phosphatosulfate having P–O–Slinkage were investigated. Metalions examined were found to be divided into two different groups in the manner of cleavage of P–O–Slinkage: Mg2+, Cr3+, Cu2+, Mn2+, and Ca2+ with larger ionic radii catalyzed the selective P–O bond cleavage, while Be2+, Al3+, Fe2+, and Zn2+ with smaller ionic radii promoted the selective S–O
Structure and Mechanism of PhnP, a Phosphodiesterase of the Carbon-Phosphorus Lyase Pathway
作者:Shu-Mei He、Matthew Wathier、Kateryna Podzelinska、Matthew Wong、Fern R. McSorley、Alemayehu Asfaw、Bjarne Hove-Jensen、Zongchao Jia、David L. Zechel
DOI:10.1021/bi2005398
日期:2011.10.11
PhnP is a phosphodiesterase that plays an important role within the bacterial carbon-phosphoruslyase (CP-lyase) pathway by recycling a “dead-end” intermediate, 5-phospho-α-d-ribosyl 1,2-cyclic phosphate, that is formed during organophosphonate catabolism. As a member of the metallo-β-lactamase superfamily, PhnP is most homologous in sequence and structure to tRNase Z phosphodiesterases. X-ray structural
PhnP是一种磷酸二酯酶,通过回收“末端”中间体5-磷酸-α- d在细菌碳-磷裂解酶(CP-裂解酶)途径中发挥重要作用。-核糖基1,2-环磷酸酯,在有机膦酸酯分解代谢过程中形成。作为金属-β-内酰胺酶超家族的成员,PnP在序列和结构上与tRNase Z磷酸二酯酶最同源。用PhnP与原钒酸酯络合至1.5Å分辨率的X射线结构分析表明,该抑制剂在四面体几何结构中被两个催化锰离子和推定的一般酸残基H200结合。在这种结构的指导下,我们通过定点诱变,动力学分析和ICP-MS探索了第一和第二球活性位点残基对催化和金属离子结合的贡献。H200变为丙氨酸导致k cat / K M降低6–33倍带有取代的甲基苯基磷酸二酯,离去基团p K a的值在4至8.4之间。以双(对硝基苯基)磷酸酯为底物,k cat / K M降低了10倍,这主要是由于K M大大增加的结果。此外,镍离子活化的H200A PhnP对k cat
Cd<sup>2+</sup>-Catalyzed Methanolysis of Phenyl Phosphatosulfate. Selectivity of Metal Ion in the Site of Cleavage of P–O and S–O Bond
It was reported previously that metalions such as Mg2+, Cr3+, Cu2+, Mn2+, and Ca2+ catalyzed selective P–O bond cleavage of P–O–Slinkage in the methanolysis of phenyl phosphatosulfate (PPS), and in contrast, metalions such as Zn2+, Fe3+, Al3+, and Be2+ promoted selective S–O bond cleavage.1) We have now found that Cd2+ catalyzes mixed cleavage of P–O and S–O bond in a ratio of 58 and 42%, respectively
Alkaline Phosphatase Mono- and Diesterase Reactions: Comparative Transition State Analysis
作者:Jesse G. Zalatan、Daniel Herschlag
DOI:10.1021/ja056528r
日期:2006.2.1
Escherichia coli alkaline phosphatase (AP), however, suggests that this enzyme catalyzes the hydrolysis of phosphatemonoesters through a loose, dissociative transition state, similar to that in solution. AP also exhibits catalytic promiscuity, with a low level of phosphodiesterase activity, despite the tighter, more associative transition state for phosphatediesterhydrolysis in solution. Because AP
经常建议酶催化的磷酰基转移反应通过从其溶液对应物改变的过渡态进行。然而,先前对大肠杆菌碱性磷酸酶 (AP) 的研究表明,这种酶通过松散的解离过渡态催化磷酸单酯的水解,类似于溶液中的过渡态。尽管在溶液中磷酸二酯水解具有更紧密、更缔合的过渡态,但 AP 还表现出催化混杂,具有低水平的磷酸二酯酶活性。因为 AP 在进化上针对磷酸单酯水解进行了优化,所以活性位点环境可能会改变二酯水解的过渡状态,使其与传入和传出基团的键合更松散。为了测试这种可能性,我们已经测量了一系列取代的甲基苯基磷酸二酯的非酶促和 AP 催化的反应速率。beta(lg) 的值和其他数据表明 AP 催化的磷酸二酯水解的过渡态与溶液中的过渡态无法区分。AP 通过识别和稳定类似于水溶液中的过渡态来催化磷酰基转移反应,而不是改变过渡态结构。因此,AP 活性位点能够识别不同的过渡状态,这一特性有助于混杂活动的进化优化。beta(lg) 的值和其他数据表明