Insights into the reaction mechanism of CO oxidative coupling to dimethyl oxalate over palladium: a combined DFT and IR study

2015 ◽  
Vol 17 (14) ◽  
pp. 9126-9134 ◽  
Author(s):  
Qiaohong Li ◽  
Zhangfeng Zhou ◽  
Ruiping Chen ◽  
Baozhen Sun ◽  
Luyang Qiao ◽  
...  
Keyword(s):  
Reaction Mechanism ◽  
Oxidative Coupling ◽  
Catalytic Mechanism ◽  
Dimethyl Oxalate ◽  
Toxic Pollutant ◽  
Ir Study ◽  
Chemical Material

Oxidative coupling of toxic pollutant CO to form the platform raw chemical material dimethyl oxalate (DMO) has been industrialized however the catalytic mechanism has been unknown so far.

scholarly journals Catalytic mechanism of the colistin resistance protein MCR-1

2021 ◽  
Author(s):  
Reynier Suardíaz ◽  
Emily Lythell ◽  
Philip Hinchliffe ◽  
Marc van der Kamp ◽  
James Spencer ◽  
...  
Keyword(s):  
Reaction Mechanism ◽  
Antimicrobial Resistance ◽  
Dft Calculations ◽  
Catalytic Reaction ◽  
Catalytic Mechanism ◽  
Cluster Models ◽  
Colistin Resistance ◽  
Resistance Protein ◽  
Catalytic Reaction Mechanism

Elucidation of the catalytic reaction mechanism of MCR-1 enzyme, responsible for the antimicrobial resistance to colistin, using DFT calculations on cluster models.

Enhanced metal-support interaction between Pd and hierarchical Nb2O5 via oxygen defects induction to promote CO oxidative coupling to dimethyl oxalate

Nanoscale ◽  
2021 ◽  
Author(s):  
Hong-Zi Tan ◽  
Yu-Ping Xu ◽  
Siteng Rong ◽  
Rongrong Zhao ◽  
Hongyou Cui ◽  
...  
Keyword(s):  
Ethylene Glycol ◽  
Oxidative Coupling ◽  
Dimethyl Oxalate ◽  
Support Interaction ◽  
Oxygen Defects ◽  
Metal Support Interaction ◽  
Metal Support

Production of ethylene glycol from coal is a particularly interesting route as it is an economic alternative of the petrochemical-based route. In this process, effectively generating dimethyl oxalate (DMO) is...

scholarly journals Catalytic Mechanism of the Colistin Resistance Protein MCR-1

2020 ◽  
Author(s):  
Reynier Suardiaz ◽  
Emily Lythell ◽  
Philip Hinchliffed ◽  
Marc van der Kamp ◽  
James Spencer ◽  
...  
Keyword(s):  
Reaction Mechanism ◽  
Lipid A ◽  
Catalytic Mechanism ◽  
Second Step ◽  
Colistin Resistance ◽  
Membrane Bound ◽  
Resistance Protein ◽  
Phosphoethanolamine Transferases ◽  
Bacterial Lipid ◽  
Rate Limiting

<div> <div> <div> <p>The mcr-1 gene encodes a membrane-bound Zn2+-metalloenzyme, MCR-1, which catalyzes phosphoethanolamine transfer onto bacterial lipid A, making bacteria resistant to colistin, a last-resort antibiotic. Mechanistic understanding of this process remains incomplete. Here, we investigate possible catalytic pathways using DFT and ab initio calculations on cluster models and identify a complete two-step reaction mechanism. The first step, formation of a covalent phosphointermediate via trans-fer of phosphoethanolamine from a membrane phospholipid donor to the acceptor Thr285, is rate-limiting and proceeds with a single Zn2+ ion. The second step, transfer of the phosphoethanolamine group to lipid A, requires an additional Zn2+. The calculations suggest the involment of the Zn2+ orbitals directly in the reaction is limited, with the second Zn2+ acting to bind incoming lipid A and direct phosphoethanolamine addition. The new level of mechanistic detail obtained here, which distinguishes these enzymes from other phosphotransferases, will aid in the development of inhibitors specific to MCR-1 and related bacterial phosphoethanolamine transferases. </p> </div> </div> </div>

Structural basis for the catalytic mechanism of homoserine dehydrogenase

2015 ◽  
Vol 71 (5) ◽  
pp. 1216-1225 ◽  
Author(s):  
Vikas Navratna ◽  
Govardhan Reddy ◽  
Balasubramanian Gopal
Keyword(s):  
Reaction Mechanism ◽  
Catalytic Mechanism ◽  
Mutational Analysis ◽  
Hydride Transfer ◽  
Structural Basis ◽  
Homoserine Dehydrogenase ◽  
Transfer Step ◽  
Conserved Water Molecules ◽  
Acid Pathway

Homoserine dehydrogenase (HSD) is an oxidoreductase in the aspartic acid pathway. This enzyme coordinates a critical branch point of the metabolic pathway that leads to the synthesis of bacterial cell-wall components such as L-lysine andm-DAP in addition to other amino acids such as L-threonine, L-methionine and L-isoleucine. Here, a structural rationale for the hydride-transfer step in the reaction mechanism of HSD is reported. The structure ofStaphylococcus aureusHSD was determined at different pH conditions to understand the basis for the enhanced enzymatic activity at basic pH. An analysis of the crystal structure revealed that Lys105, which is located at the interface of the catalytic and cofactor-binding sites, could mediate the hydride-transfer step of the reaction mechanism. The role of Lys105 was subsequently confirmed by mutational analysis. Put together, these studies reveal the role of conserved water molecules and a lysine residue in hydride transfer between the substrate and the cofactor.

THEORETICAL INVESTIGATION OF THE HIGH-SPIN "Fe-PROXIMAL OXYGEN" CATALYTIC MECHANISM OF RAT CYSTEINE DIOXYGENASE

2013 ◽  
Vol 12 (03) ◽  
pp. 1350001 ◽  
Author(s):  
XIN CHE ◽  
JUN GAO ◽  
LIKAI DU ◽  
CHENGBU LIU
Keyword(s):  
Reaction Mechanism ◽  
Oxygen Atom ◽  
High Spin ◽  
Energy Barrier ◽  
Catalytic Mechanism ◽  
Membered Ring ◽  
Cysteine Dioxygenase ◽  
Sulfinic Acid ◽  
Additional Insight ◽  
Cysteine Sulfinic Acid

Cysteine dioxygenase (CDO) catalyzes the oxidation of cysteine to cysteine sulfinate, which has crucial roles in the metabolism and bioconversion. The catalyzed reaction mechanism of CDO is currently disputed. Herein, a high-spin " Fe -proximal oxygen" catalytic mechanism of rat CDO is theoretically investigated with an energy barrier of 15.7 kcal⋅mol-1. In the mechanism, the Fe -proximal oxygen atom firstly attacks the sulfur atom of cysteine by the swing of O (1)– O (2) bond, and this makes the Fe -proximal oxygen atom O (1) accessible to S and Fe -terminal oxygen atom O (2) be closed to Fe . Then the generated seven-membered ring intermediate has smaller tension and could help the reaction take place easily. The reaction ends in the formation of the product cysteine sulfinic acid with the second oxygen atom O (2) transferred to S. This study gives an additional insight of the reaction mechanism of CDO, where the " Fe -proximal oxygen" and " Fe -terminal oxygen" mechanisms are both favorable in the catalytic process.

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