Suppressing the active site-blocking impact of ligands of Ni6(SR)12 clusters with the assistance of NH3 on catalytic hydrogenation of nitriles

Nanoscale ◽  
2018 ◽  
Vol 10 (41) ◽  
pp. 19375-19382 ◽  
Author(s):  
Xiaoqi Chai ◽  
Tao Li ◽  
Mingyang Chen ◽  
Rongchao Jin ◽  
Weiping Ding ◽  
...  
Keyword(s):  
Catalytic Hydrogenation ◽  
Active Site ◽  
Shielding Effect ◽  
Site Blocking ◽  
Hydrogenation Of Nitriles

The activity of Ni6(SR)12 for nitriles hydrogenation is enhanced with the assistance of NH3 that suppresses the ligand shielding effect.

Isozymes inhibited by active site blocking: versatility of calcium indifferent hesperidin binding to phospholipase A2 and its significance

2019 ◽  
Vol 39 (1) ◽  
pp. 60-66
Author(s):  
J. Abhithaj ◽  
K. G. Arun ◽  
C. S. Sharanya ◽  
M. Haridas ◽  
E. Jayadevi Variyar
Keyword(s):  
Phospholipase A2 ◽  
Active Site ◽  
Site Blocking

Atomically dispersed Ni as the active site towards selective hydrogenation of nitroarenes

2019 ◽  
Vol 21 (3) ◽  
pp. 704-711 ◽  
Author(s):  
Fan Yang ◽  
Minjian Wang ◽  
Wei Liu ◽  
Bin Yang ◽  
Ying Wang ◽  
...  
Keyword(s):  
Noble Metal ◽  
Catalytic Hydrogenation ◽  
Selective Hydrogenation ◽  
Porous Carbon ◽  
Active Site ◽  
Active Sites ◽  
Rational Design ◽  
Metal Free

Noble-metal-free catalytic hydrogenation of nitroarenes is achieved through the rational design of atomically dispersed Ni sites on N-doped porous carbon. The outstanding activity of the catalyst originates from the atomic dispersion of Ni active sites with a high Ni–N3 content.

Influence of spin state and electron configuration on the active site and mechanism for catalytic hydrogenation on metal cation catalysts supported on NU-1000: insights from experiments and microkinetic modeling

2020 ◽  
Vol 10 (11) ◽  
pp. 3594-3602 ◽  
Author(s):  
Hafeera Shabbir ◽  
Steven Pellizzeri ◽  
Magali Ferrandon ◽  
In Soo Kim ◽  
Nicolaas A. Vermeulen ◽  
...  
Keyword(s):  
Spin State ◽  
Catalytic Hydrogenation ◽  
Metal Cation ◽  
Active Site ◽  
Electron Configuration ◽  
Microkinetic Modeling

Spin state is found to determine the mechanism and active site of catalytic hydrogenation on metal cation catalysts.

scholarly journals Enhancing the α-Cyclodextrin Specificity of Cyclodextrin Glycosyltransferase from Paenibacillus macerans by Mutagenesis Masking Subsite −7

2016 ◽  
Vol 82 (8) ◽  
pp. 2247-2255 ◽  
Author(s):  
Lei Wang ◽  
Xuguo Duan ◽  
Jing Wu
Keyword(s):  
Active Site ◽  
Wild Type ◽  
Cyclodextrin Glycosyltransferase ◽  
Wild Type Enzyme ◽  
Widespread Application ◽  
Content Type ◽  
Hydrogen Bonding Interactions ◽  
Paenibacillus Macerans ◽  
Site Blocking ◽  
Cyclodextrin Production

ABSTRACTCyclodextrin glycosyltransferases (CGTases) (EC 2.4.1.19) catalyze the conversion of starch or starch derivates into mixtures of α-, β-, and γ-cyclodextrins. Because time-consuming and expensive purification procedures hinder the widespread application of single-ingredient cyclodextrins, enzymes with enhanced specificity are needed. In this study, we tested the hypothesis that the α-cyclodextrin selectivity ofPaenibacillus maceransα-CGTase could be augmented by masking subsite −7 of the active site, blocking the formation of larger cyclodextrins, particularly β-cyclodextrin. Five single mutants and three double mutants designed to remove hydrogen-bonding interactions between the enzyme and substrate at subsite −7 were constructed and characterized in detail. Although the rates of α-cyclodextrin formation varied only modestly, the rate of β-cyclodextrin formation decreased dramatically in these mutants. The increase in α-cyclodextrin selectivity was directly proportional to the increase in the ratio of theirkcatvalues for α- and β-cyclodextrin formation. The R146A/D147P and R146P/D147A double mutants exhibited ratios of α-cyclodextrin to total cyclodextrin production of 75.1% and 76.1%, approximately one-fifth greater than that of the wild-type enzyme (63.2%), without loss of thermostability. Thus, these double mutants may be more suitable for the industrial production of α-cyclodextrin than the wild-type enzyme. The production of β-cyclodextrin by these mutants was almost identical to their production of γ-cyclodextrin, which was unaffected by the mutations in subsite −7, suggesting that subsite −7 was effectively blocked by these mutations. Further increases in α-cyclodextrin selectivity will require identification of the mechanism or mechanisms by which these small quantities of larger cyclodextrins are formed.

scholarly journals Inhibition of Plasma Kallikrein by a Highly Specific Active Site Blocking Antibody

2014 ◽  
Vol 289 (34) ◽  
pp. 23596-23608 ◽  
Author(s):  
Jon A. Kenniston ◽  
Ryan R. Faucette ◽  
Diana Martik ◽  
Stephen R. Comeau ◽  
Allison P. Lindberg ◽  
...  
Keyword(s):  
Active Site ◽  
Plasma Kallikrein ◽  
Blocking Antibody ◽  
Site Blocking
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