Transition State Analysis of the Reaction Catalyzed by the Phosphotriesterase from <i>Sphingobium</i> sp. TCM1
作者:Andrew N. Bigley、Dao Feng Xiang、Tamari Narindoshvili、Charlie W. Burgert、Alvan C. Hengge、Frank M. Raushel
DOI:10.1021/acs.biochem.9b00041
日期:2019.3.5
emerging pollutants. The phosphotriesterase from Sphingobium sp. TCM1 (Sb-PTE) is one of the few enzymes known to be able to hydrolyze organophosphorus flame retardants such as triphenyl phosphate and tris(2-chloroethyl) phosphate. The effectiveness of Sb-PTE for the hydrolysis of these organophosphates appears to arise from its ability to hydrolyze unactivated alkyl and phenolic esters from the central phosphorus
有机磷阻燃剂是几乎所有耐久的塑料产品中使用的稳定有毒化合物,被认为是主要的新兴污染物。鞘氨醇单胞菌属的磷酸三酯酶。TCM1(Sb -PTE)是已知能够水解有机磷阻燃剂(如磷酸三苯酯和磷酸三(2-氯乙基)酯)的几种酶之一。Sb- PTE水解这些有机磷酸酯的有效性似乎是由于其水解来自中心磷核的未活化的烷基和酚酯的能力而产生的。Sb- PTE如何能够催化未活化取代基的水解是未知的。探讨Sb的催化水解机理确定了-PTE,反应的pH依赖性以及改变溶剂粘度的影响。通过测量初级和次级18氧同位素对底物水解的影响并确定改变p K a的影响来补充这些实验。离去基团对水解速率常数大小的影响。总体而言,结果表明单个基团必须被离子化以引起亲核攻击,并且单独的普通酸不涉及离去基团的质子化。布朗斯台德分析和重原子动力学同位素效应与早期缔合过渡态相符,随后的质子转移不受速率的限制。提出了底物与双核金属中心的新型结合方式和催化机理,以解释Sb-
LiI/TBHP Mediated Oxidative Cross-Coupling of P(O)-H Compounds with Phenols and Various Nucleophiles: Direct Access to the Synthesis of Organophosphates
Direct phosphorylation of P(O)–H compounds with various nucleophiles such as phenols, alcohols, amines and enols is described using oxidative cross‐coupling strategy. The phosphorylation of hydroxylated naphthyls and heteroarenes has been achieved. Main features of this transformation are short reaction time, functional group tolerance, and broad substrate scope.