Nanostructured manganese oxides as highly active catalysts for enhanced hydrolysis of bis(4-nitrophenyl)phosphate and catalytic decomposition of methanol

2021 ◽  
Author(s):  
Martin Šťastný ◽  
Gloria Issa ◽  
Daniela Popelková ◽  
Jakub Ederer ◽  
Martin Kormunda ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Manganese Oxides ◽  
Catalytic Decomposition ◽  
Alternative Fuel ◽  
Catalytic Activities ◽  
Highly Active ◽  
Phosphate Diester ◽  
Nitrophenyl Phosphate ◽  
Potential Alternative ◽  
Hydrolysis Of

The nanostructured manganese oxides (MnOx) exhibited high catalytic activities for hydrolysis of phosphate diester-based substrate bis(4-nitrophenyl)phosphate and decomposition of methanol to carbon monoxide and hydrogen as a potential alternative fuel.

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.

Hydrolysis of phosphate diester catalysed by transition metal complexes of a salicylaldimine Schiff base bearing dibenzo-18-crown-6

2005 ◽  
Vol 2005 (2) ◽  
pp. 130-134 ◽  
Author(s):  
Jin Zhang ◽  
Jia-qing Xie ◽  
Ying Tang ◽  
Jun Li ◽  
Jian-zhang Li ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Schiff Base ◽  
Crown Ether ◽  
Transition Metal Complexes ◽  
Catalytic Hydrolysis ◽  
Reaction Conditions ◽  
Reaction Systems ◽  
Phosphate Diester ◽  
Nitrophenyl Phosphate ◽  
Hydrolysis Of

A new crowned Schiff base ligand and its cobalt(II) and manganese(III) complexes were synthesised and characterised. These complexes were used to catalyse the hydrolysis of bis(4-nitrophenyl) phosphate (BNPP) in order to mimic the action of hydrolytic metalloenzymes. The kinetics and the mechanism of the titled reactions were investigated. The change of the characteristic ultraviolet spectra of the reaction systems was also analysed. A kinetic mathematical model of BNPP cleavage catalysed by the complexes is proposed. The function of the crown ether ring and the effects of the reaction conditions on the catalytic hydrolysis of BNPP are discussed.

Highly active copper-based Ce@TiO2 core-shell catalysts for the selective reduction of nitric oxide with carbon monoxide in the presence of oxygen

2018 ◽  
Vol 104 ◽  
pp. 17-21 ◽  
Author(s):  
Naima López ◽  
Gonzalo Aguila ◽  
Paulo Araya ◽  
Sichem Guerrero
Keyword(s):  
Nitric Oxide ◽  
Carbon Monoxide ◽  
Selective Reduction ◽  
Core Shell ◽  
Highly Active

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.

scholarly journals Catalytic activity and stereoselectivity of engineered phosphotriesterases towards structurally different nerve agents in vitro

2021 ◽  
Author(s):  
Anja Köhler ◽  
Benjamin Escher ◽  
Laura Job ◽  
Marianne Koller ◽  
Horst Thiermann ◽  
...  
Keyword(s):  
Plasma Clearance ◽  
Nerve Agents ◽  
Inhibition Assay ◽  
Ache Inhibition ◽  
Catalytic Activities ◽  
Chiral Lc ◽  
Hydrolysis Of ◽  
Medical Countermeasures

AbstractHighly toxic organophosphorus nerve agents, especially the extremely stable and persistent V-type agents such as VX, still pose a threat to the human population and require effective medical countermeasures. Engineered mutants of the Brevundimonas diminuta phosphotriesterase (BdPTE) exhibit enhanced catalytic activities and have demonstrated detoxification in animal models, however, substrate specificity and fast plasma clearance limit their medical applicability. To allow better assessment of their substrate profiles, we have thoroughly investigated the catalytic efficacies of five BdPTE mutants with 17 different nerve agents using an AChE inhibition assay. In addition, we studied one BdPTE version that was fused with structurally disordered PAS polypeptides to enable delayed plasma clearance and one bispecific BdPTE with broadened substrate spectrum composed of two functionally distinct subunits connected by a PAS linker. Measured kcat/KM values were as high as 6.5 and 1.5 × 108 M−1 min−1 with G- and V-agents, respectively. Furthermore, the stereoselective degradation of VX enantiomers by the PASylated BdPTE-4 and the bispecific BdPTE-7 were investigated by chiral LC–MS/MS, resulting in a several fold faster hydrolysis of the more toxic P(−) VX stereoisomer compared to P(+) VX. In conclusion, the newly developed enzymes BdPTE-4 and BdPTE-7 have shown high catalytic efficacy towards structurally different nerve agents and stereoselectivity towards the toxic P(−) VX enantiomer in vitro and offer promise for use as bioscavengers in vivo.

ISOBAM-stabilized Ni2+ colloidal catalysts: high catalytic activities for hydrogen generation from hydrolysis of KBH4

2020 ◽  
Vol 31 (13) ◽  
pp. 134003 ◽  
Author(s):  
Yuantao Pei ◽  
Liqiong Wang ◽  
Liang Huang ◽  
Yuetong Hu ◽  
Quanli Jia ◽  
...  
Keyword(s):  
Hydrogen Generation ◽  
Catalytic Activities ◽  
Hydrolysis Of

scholarly journals Preparation of Al/Fe-PILC clay catalysts from concentrated precursors: enhanced hydrolysis of pillaring metals and intercalation

RSC Advances ◽  
2020 ◽  
Vol 10 (66) ◽  
pp. 40450-40460
Author(s):  
Carlos Andrés Vallejo ◽  
Luis Alejandro Galeano ◽  
Raquel Trujillano ◽  
Miguel Ángel Vicente ◽  
Antonio Gil
Keyword(s):  
Solvent Free ◽  
Peroxide Oxidation ◽  
Highly Active ◽  
Wet Peroxide Oxidation ◽  
Catalytic Wet Peroxide Oxidation ◽  
Hydrolysis Of ◽  
Clay Catalysts

Significantly intensified preparation of Al/Fe-hydrolysed-pillaring solutions and solvent-free intercalation of bentonites yielding Al/Fe-PILCs highly active in catalytic wet peroxide oxidation.

Nanostructured Manganese Oxides as Highly Active Water Oxidation Catalysts: A Boost from Manganese Precursor Chemistry

ChemSusChem ◽  
2014 ◽  
Vol 7 (8) ◽  
pp. 2202-2211 ◽  
Author(s):  
Prashanth W. Menezes ◽  
Arindam Indra ◽  
Patrick Littlewood ◽  
Michael Schwarze ◽  
Caren Göbel ◽  
...  
Keyword(s):  
Water Oxidation ◽  
Manganese Oxides ◽  
Precursor Chemistry ◽  
Oxidation Catalysts ◽  
Highly Active ◽  
Manganese Precursor

Catalytic Hydrolysis of 4-Nitrophenyl Phosphate by Lanthanum(III)-Hectorite

Langmuir ◽  
2003 ◽  
Vol 19 (6) ◽  
pp. 2188-2192 ◽  
Author(s):  
Steven T. Frey ◽  
Benjamin M. Hutchins ◽  
Brian J. Anderson ◽  
Teresa K. Schreiber ◽  
Michael E. Hagerman
Keyword(s):  
Catalytic Hydrolysis ◽  
Nitrophenyl Phosphate ◽  
Hydrolysis Of

scholarly journals Phosphatase synthesis in Klebsiella (Aerobacter) aerogenes growing in continuous culture

1972 ◽  
Vol 127 (1) ◽  
pp. 87-96 ◽  
Author(s):  
P. G. Bolton ◽  
A. C. R. Dean
Keyword(s):  
Alkaline Phosphatase ◽  
Acid Phosphatase ◽  
Continuous Culture ◽  
Activity Profile ◽  
Glucose Effect ◽  
Ph Values ◽  
Nitrophenyl Phosphate ◽  
Wide Range ◽  
Rate Of Hydrolysis ◽  
Hydrolysis Of

1. Phosphatase synthesis was studied in Klebsiella aerogenes grown in a wide range of continuous-culture systems. 2. Maximum acid phosphatase synthesis was associated with nutrient-limited, particularly carbohydrate-limited, growth at a relatively low rate, glucose-limited cells exhibiting the highest activity. Compared with glucose as the carbon-limiting growth material, other sugars not only altered the activity but also changed the pH–activity profile of the enzyme(s). 3. The affinity of the acid phosphatase in glucose-limited cells towards p-nitrophenyl phosphate (Km 0.25–0.43mm) was similar to that of staphylococcal acid phosphatase but was ten times greater than that of the Escherichia coli enzyme. 4. PO43−-limitation derepressed alkaline phosphatase synthesis but the amounts of activity were largely independent of the carbon source used for growth. 5. The enzymes were further differentiated by the effect of adding inhibitors (F−, PO43−) and sugars to the reaction mixture during the assays. In particular, it was shown that adding glucose, but not other sugars, stimulated the rate of hydrolysis of p-nitrophenyl phosphate by the acid phosphatase in carbohydrate-limited cells at low pH values (<4.6) but inhibited it at high pH values (>4.6). Alkaline phosphatase activity was unaffected. 6. The function of phosphatases in general is discussed and possible mechanisms for the glucose effect are outlined.

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