scholarly journals Vaccinia topoisomerase and Cre recombinase catalyze direct ligation of activated DNA substrates containing a 3'-para-nitrophenyl phosphate ester

2000 ◽  
Vol 28 (17) ◽  
pp. 3323-3331 ◽  
Author(s):  
G. Woodfield
Keyword(s):  
Cre Recombinase ◽  
Phosphate Ester ◽  
Nitrophenyl Phosphate ◽  
Dna Substrates

The Study of the Hydrolysis of the Phosphate Diester Catalyzed by an Anion Metallomicelle of Ce3+-Diethylenetriamine

2012 ◽  
Vol 554-556 ◽  
pp. 353-356
Author(s):  
Shu Lan Cai ◽  
Fa Mei Feng ◽  
Tao Wang ◽  
Xiu Lan Zhang
Keyword(s):  
Critical Micelle Concentration ◽  
High Activity ◽  
Catalytic Efficiency ◽  
Active Species ◽  
Phosphate Ester ◽  
Catalytic Hydrolysis ◽  
Phosphate Diester ◽  
Nitrophenyl Phosphate ◽  
Hydrolysis Of ◽  
Lauroyl Sarcosinate

The catalytic hydrolysis of Bis(p-nitrophenyl) phosphate ester (BNPP) in the metallomicelle made up of Ce3+-diethylenetriamine and LSS (N-lauroyl sarcosinate) was investigated by UV/VIS method. The effect of the catalytic efficiency and stability of the system was studied under the different conditions. The results indicated that the catalytic system exhibited high activity, stability and reproducibility in the BNPP catalytic hydrolysis under proper proportion of Ce3+ion and diethylenetriamine, pH and temperature when the concentration of LSS is higher than its CMC (critical micelle concentration). The results also showed that the active species is the complex made up of Ce3+ion and diethylenetriamine.

The Study of the Degradation of the Phosphate Ester Catalyzed by the Nitrogen Unsaturated Heterocycle Cerium(III) Complex

2012 ◽  
Vol 518-523 ◽  
pp. 541-544
Author(s):  
Fa Mei Feng ◽  
Xi Yang He ◽  
Tao Wang
Keyword(s):  
Catalytic Activity ◽  
Catalytic System ◽  
Environmental Concern ◽  
Catalytic Degradation ◽  
Phosphate Ester ◽  
Effective Catalyst ◽  
Nitrophenyl Phosphate ◽  
Cerium Ion

Phosphate ester and its ramifications in the pesticide are virulent and some are known to be human carcinogens. The removal of phosphate ester in the leftover of the pesticide has been a major environmental concern. The Cerium(III) complex made up of a nitrogen unsaturated heterocycle ligand and Cerium ion(III) was used in the catalytic degradation of bis(4-nitrophenyl) phosphate ester (BNPP). This catalytic system showed higher catalytic activity and better reproducibility and stability than other similar Cerium(III) systems. The rate of the BNPP catalytic degradation was about 109 -fold faster than that of its spontaneous degradation at the same conditions. The Cerium(III) complex is an very effective catalyst in the degradation of the phosphate ester.

Intramolecular Nucleophilic Substitution in the Hydrolysis of Bis(4-Nitrophenyl) Phosphate Ester Catalyzed by the Metallomicelle

2012 ◽  
Vol 554-556 ◽  
pp. 345-348
Author(s):  
Min Wang ◽  
Li Qin Xu ◽  
Ci Li ◽  
Bing Ying Jiang ◽  
Jia Qing Xie
Keyword(s):  
Nucleophilic Substitution ◽  
Absorption Spectra ◽  
Catalytic Efficiency ◽  
Phosphate Ester ◽  
Catalytic Hydrolysis ◽  
Characteristic Absorption ◽  
Intramolecular Nucleophilic Substitution ◽  
Nitrophenyl Phosphate ◽  
Hydrolytic Reaction ◽  
Hydrolysis Of

A macro-cyclic Schiff base ligand and the corresponding Cu (II) and Ni (II) complexes were synthesized and characterized. And the catalytic efficiency of the metallomicelles made of these complexes and noninonic micelle Brij35, as mimetic hydrolytic metalloenzyme, was investigated in the catalytic hydrolysis of bis(p-nitrophenyl) phosphate (BNPP) in this paper. The results show that the rate of the BNPP hydrolysis in the metallomicelles is about 106 -fold faster than that of the BNPP spontaneous hydrolysis in aqueous solution at the same conditions. The analysis of the characteristic absorption spectra of the hydrolytic reaction systems indicates that the key intermediate, composing of BNPP and Ni(II) or Cu(II) complexes, has been formed and the catalytic hydrolysis of BNPP is an intramolecular nucleophilic substitution reaction. Based on the results of characteristic absorption spectra, the mechanism of BNPP catalytic hydrolysis has been proposed and also the corresponding kinetic mathematical model has been established.

Substituent Effects on the Thermal Decomposition of Phosphate Esters on Ferrous Surfaces

2019 ◽  
Author(s):  
James Ewen ◽  
Carlos Ayestaran Latorre ◽  
Arash Khajeh ◽  
Joshua Moore ◽  
Joseph Remias ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Film Formation ◽  
Substituent Effects ◽  
Vapour Phase ◽  
Industrial Applications ◽  
Phosphate Esters ◽  
Antiwear Additives ◽  
Formation Mechanisms ◽  
Phosphate Ester ◽  
Wide Range

<p>Phosphate esters have a wide range of industrial applications, for example in tribology where they are used as vapour phase lubricants and antiwear additives. To rationally design phosphate esters with improved tribological performance, an atomic-level understanding of their film formation mechanisms is required. One important aspect is the thermal decomposition of phosphate esters on steel surfaces, since this initiates film formation. In this study, ReaxFF molecular dynamics simulations are used to study the thermal decomposition of phosphate esters with different substituents on several ferrous surfaces. On Fe<sub>3</sub>O<sub>4</sub>(001) and α-Fe(110), chemisorption interactions between the phosphate esters and the surfaces occur even at room temperature, and the number of molecule-surface bonds increases as the temperature is increased from 300 to 1000 K. Conversely, on hydroxylated, amorphous Fe<sub>3</sub>O<sub>4</sub>, most of the molecules are physisorbed, even at high temperature. Thermal decomposition rates were much higher on Fe<sub>3</sub>O<sub>4</sub>(001) and particularly α-Fe(110) compared to hydroxylated, amorphous Fe<sub>3</sub>O<sub>4</sub>. This suggests that water passivates ferrous surfaces and inhibits phosphate ester chemisorption, decomposition, and ultimately film formation. On Fe<sub>3</sub>O<sub>4</sub>(001), thermal decomposition proceeds mainly through C-O cleavage (to form surface alkyl and aryl groups) and C-H cleavage (to form surface hydroxyls). The onset temperature for C-O cleavage on Fe<sub>3</sub>O<sub>4</sub>(001) increases in the order: tertiary alkyl < secondary alkyl < primary linear alkyl ≈ primary branched alkyl < aryl. This order is in agreement with experimental observations for the thermal stability of antiwear additives with similar substituents. The results highlight surface and substituent effects on the thermal decomposition of phosphate esters which should be helpful for the design of new molecules with improved performance.</p>

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