Epoxidation Reaction of Unsaturated Hydrocarbons with H2O2 over Defect TS-1 Investigated by ONIOM Method:  Formation of Active Sites and Reaction Mechanisms

2007 ◽  
Vol 111 (8) ◽  
pp. 3433-3441 ◽  
Author(s):  
Weerayuth Panyaburapa ◽  
Tanin Nanok ◽  
Jumras Limtrakul
Keyword(s):  
Reaction Mechanisms ◽  
Active Sites ◽  
Unsaturated Hydrocarbons ◽  
Epoxidation Reaction ◽  
Oniom Method

scholarly journals Structure and mechanism of potent bifunctional β-lactam- and homoserine lactone-degrading enzymes from marine microorganisms

2020 ◽  
Author(s):  
Christopher Selleck ◽  
Marcelo Monteiro Pedroso ◽  
Liam Wilson ◽  
Stephan Krco ◽  
Esmée Gianna Knaven ◽  
...  
Keyword(s):  
Health Care ◽  
Antibiotic Resistance ◽  
Resistance Genes ◽  
Reaction Mechanisms ◽  
Active Sites ◽  
Homoserine Lactone ◽  
Pathogenic Microorganisms ◽  
Marine Microorganisms ◽  
Bacterial Strains ◽  
Fast Kinetics

AbstractGenes that confer antibiotic resistance can rapidly be disseminated from one microorganism to another by mobile genetic elements, thus transferring resistance to previously susceptible bacterial strains. The misuse of antibiotics in health care and agriculture has provided a powerful evolutionary pressure to accelerate the spread of resistance genes, including those encoding β-lactamases. These are enzymes that are highly efficient in inactivating most of the commonly used β-lactam antibiotics. However, genes that confer antibiotic resistance are not only associated with pathogenic microorganisms, but are also found in non-pathogenic (i.e. environmental) microorganisms. Two recent examples are metal-dependent β-lactamases (MBLs) from the marine organisms Novosphingobium pentaromativorans and Simiduia agarivorans. Previous studies have demonstrated that their β-lactamase activity is comparable to those of well-known MBLs from pathogenic sources (e.g. NDM-1, AIM-1) but that they also possess efficient lactonase activity, an activity associated with quorum sensing. Here, we probed the structure and mechanism of these two enzymes using crystallographic, spectroscopic and fast kinetics techniques. Despite highly conserved active sites both enzymes demonstrate significant variations in their reaction mechanisms, highlighting both the extraordinary ability of MBLs to adapt to changing environmental conditions and the rather promiscuous acceptance of diverse substrates by these enzymes.

scholarly journals Catalytic conversion of ethane to valuable products through non-oxidative dehydrogenation and dehydroaromatization

RSC Advances ◽  
2020 ◽  
Vol 10 (36) ◽  
pp. 21427-21453 ◽  
Author(s):  
Hikaru Saito ◽  
Yasushi Sekine
Keyword(s):  
Oxidative Dehydrogenation ◽  
Reaction Mechanisms ◽  
Active Sites ◽  
Catalytic Conversion ◽  
Ethane Dehydrogenation

This review examines the catalytic ethane dehydrogenation and dehydroaromatization in terms of characteristics of active sites and their reaction mechanisms.

Selective hydrogen-deuterium exchange in graphitic carbon nitrides: probing the active sites for photocatalytic water splitting by solid-state NMR

2021 ◽  
Author(s):  
Ruidi Wang ◽  
Beibei Xv ◽  
Jiachen Wang ◽  
Xue Lu Wang ◽  
Yefeng Yao
Keyword(s):  
Reaction Mechanisms ◽  
Solid State Nmr ◽  
Active Sites ◽  
Carbon Nitride ◽  
Molecular Level ◽  
Structural Characteristics ◽  
Graphitic Carbon ◽  
Hydrogen Deuterium Exchange ◽  
Hydrogen Deuterium ◽  
Further Development

Graphitic carbon nitride (g-C3N4), the relationships between whose structural characteristics and the photocatalytic reaction mechanisms still remains unclarified at the molecular level, severely hinders the further development of this field....

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