Catalytic Mechanism and Activity of a Nitrogen Heterocycle Lanthanum(III) Complex in the Hydrolysis of bis(4-nitrophenyl) Phosphate Ester

2012 ◽  
Vol 37 (4) ◽  
pp. 398-410 ◽  
Author(s):  
Shulan Cai ◽  
Famei Feng ◽  
Like Zou ◽  
Chun Huang ◽  
Jiaqing Xie
Keyword(s):  
Catalytic Mechanism ◽  
Nitrogen Heterocycle ◽  
Phosphate Ester ◽  
Nitrophenyl Phosphate ◽  
Hydrolysis Of

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.

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.

scholarly journals Kinetics and Mechanistic Study of Hydrolysis of Adenosine Monophosphate Disodium Salt (AMPNa2) in Acidic and Alkaline Media

2019 ◽  
Vol 17 (1) ◽  
pp. 544-556
Author(s):  
Yoke-Leng Sim ◽  
Beljit Kaur
Keyword(s):  
Rate Constant ◽  
Adenosine Monophosphate ◽  
Disodium Salt ◽  
Second Order ◽  
Information Storage ◽  
Alkaline Media ◽  
Basic Medium ◽  
Mechanistic Study ◽  
Phosphate Ester ◽  
Hydrolysis Of

AbstractPhosphate ester hydrolysis is essential in signal transduction, energy storage and production, information storage and DNA repair. In this investigation, hydrolysis of adenosine monophosphate disodium salt (AMPNa2) was carried out in acidic, neutral and alkaline conditions of pH ranging between 0.30-12.71 at 60°C. The reaction was monitored spectrophotometrically. The rate ranged between (1.20 ± 0.10) × 10-7 s-1 to (4.44 ± 0.05) × 10-6 s-1 at [NaOH] from 0.0008 M to 1.00M recorded a second-order base-catalyzed rate constant, kOH as 4.32 × 10-6 M-1 s-1. In acidic conditions, the rate ranged between (1.32 ± 0.06) × 10-7 s-1 to (1.67 ± 0.10) × 10-6 s-1 at [HCl] from 0.01 M to 1.00 M. Second-order acid-catalyzed rate constant, kH obtained was 1.62 × 10-6 M-1 s-1. Rate of reaction for neutral region, k0 was obtained from graphical method to be 10-7 s-1. Mechanisms were proposed to involve P-O bond cleavage in basic medium while competition between P-O bond and N-glycosidic cleavage was observed in acidic medium. In conclusion, this study has provided comprehensive information on the kinetic parameters and mechanism of cleavage of AMPNa2 which mimicked natural AMP cleavage and the action of enzymes that facilitate its cleavage.

scholarly journals Renal sodium-potassium adenosine triphosphatase. Optical localization and x-ray microanalysis.

1975 ◽  
Vol 23 (11) ◽  
pp. 828-839 ◽  
Author(s):  
R Beeuwkes ◽  
S Rosen
Keyword(s):  
Atpase Activity ◽  
Electron Probe ◽  
Sequential Analysis ◽  
Relative Sensitivity ◽  
Initial Reaction ◽  
Initial Product ◽  
Sodium Potassium ◽  
Nitrophenyl Phosphate ◽  
Hydrolysis Of ◽  
Convoluted Tubules

The distribution of sodium-potassium adenosine triposphatase (Na-K-ATPase) activity in kidney sections has been studied by a method based on the hydrolysis of p-nitrophenyl phosphate in alkaline medium containing dimethyl sulfoxide. The products at each stage in the reaction sequence have been subjected to electron probe microanalysis. The initial product was identified as a mixture of KMgPO4 and Mg(PO4)2, and sequential analysis demonstrated the linearity of conversion of this product to a visible form. In human, rabbit and rat kidneys the distribution of activity was found to be essentially identical, with highest levels located in thick ascending limbs and distal convoluted tubules. The initial reaction was completely potassium dependent and was inhibited by ouabain in concentrations reflecting the relative sensitivity of microsomal Na-K-ATPase in each species. Measurement of initial product phosphorus by means of the electron probe is presented as a practical technique for direct quantitation of Na-K-ATPase activity in identified tubule segments.

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