scholarly journals Probing Active-Site Relocation in Cu/SSZ-13 SCR Catalysts during Hydrothermal Aging by In Situ EPR Spectroscopy, Kinetics Studies, and DFT Calculations

ACS Catalysis ◽  
2020 ◽  
Vol 10 (16) ◽  
pp. 9410-9419 ◽  
Author(s):  
Yani Zhang ◽  
Yue Peng ◽  
Junhua Li ◽  
Kyle Groden ◽  
Jean-Sabin McEwen ◽  
...  
Keyword(s):  
Dft Calculations ◽  
Epr Spectroscopy ◽  
Active Site ◽  
Hydrothermal Aging ◽  
Kinetics Studies ◽  
Scr Catalysts

scholarly journals Mapping the protonation states of the histidine brace in an AA10 lytic polysaccharide monooxygenase using CW-EPR spectroscopy and DFT calculations

2021 ◽  
Author(s):  
Peter J Lindley ◽  
Alison Parkin ◽  
Gideon Davies ◽  
Paul Howard Walton
Keyword(s):  
Dft Calculations ◽  
Epr Spectroscopy ◽  
Active Site ◽  
Copper Ion ◽  
Lytic Polysaccharide Monooxygenase ◽  
Polysaccharide Monooxygenase

The active site of the polysaccharide-degrading lytic polysaccharide monooxygenase (LPMO) enzymes features a single copper ion coordinated by a histidine brace. The primary coordnation sphere of the copper contains several...

scholarly journals Novel hydrogen chemisorption properties of amorphous ceramic compounds consisting of p-block elements: exploring Lewis acid-base Al–N pair site formed in-situ within polymer-derived silicon-aluminum-nitrogen-based system

2021 ◽  
Author(s):  
Shotaro Tada ◽  
Norifumi Asakuma ◽  
Shiori Ando ◽  
Toru Asaka ◽  
Yusuke Daiko ◽  
...  
Keyword(s):  
Lewis Acid ◽  
Active Site ◽  
Hydrogen Chemisorption ◽  
Acid Base ◽  
Polymer Derived Ceramics ◽  
System P ◽  
Ceramic Compounds ◽  
The Relationship

This paper reports on the relationship between the H2 chemisorption properties and reversible structural reorientation of the possible active site around Al formed in-situ within polymer-derived ceramics (PDCs) based on...

Physicochemical properties of geopolymer composites with DFT calculations of in-situ reduction of graphene oxide

2021 ◽  
Author(s):  
Amun Amri ◽  
Ahmad Ainun Najib ◽  
Monita Olivia ◽  
Mohammednoor Altarawneh ◽  
Aman Syam ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Dft Calculations ◽  
Physicochemical Properties ◽  
In Situ Reduction ◽  
Geopolymer Composites

scholarly journals Iron-Imprinted Single-Atomic Site Catalyst-Based Nanoprobe for Detection of Hydrogen Peroxide in Living Cells

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Zhaoyuan Lyu ◽  
Shichao Ding ◽  
Maoyu Wang ◽  
Xiaoqing Pan ◽  
Zhenxing Feng ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Active Site ◽  
Single Atom ◽  
Site Structure ◽  
Atomic Site ◽  
Ion Imprinting ◽  
Active Site Structure ◽  
In Situ Detection ◽  
Colorimetric Biosensing

AbstractFe-based single-atomic site catalysts (SASCs), with the natural metalloproteases-like active site structure, have attracted widespread attention in biocatalysis and biosensing. Precisely, controlling the isolated single-atom Fe-N-C active site structure is crucial to improve the SASCs’ performance. In this work, we use a facile ion-imprinting method (IIM) to synthesize isolated Fe-N-C single-atomic site catalysts (IIM-Fe-SASC). With this method, the ion-imprinting process can precisely control ion at the atomic level and form numerous well-defined single-atomic Fe-N-C sites. The IIM-Fe-SASC shows better peroxidase-like activities than that of non-imprinted references. Due to its excellent properties, IIM-Fe-SASC is an ideal nanoprobe used in the colorimetric biosensing of hydrogen peroxide (H2O2). Using IIM-Fe-SASC as the nanoprobe, in situ detection of H2O2 generated from MDA-MB-231 cells has been successfully demonstrated with satisfactory sensitivity and specificity. This work opens a novel and easy route in designing advanced SASC and provides a sensitive tool for intracellular H2O2 detection.

In situ regeneration of commercial NH3-SCR catalysts with high-temperature water vapor

2018 ◽  
Vol 116 ◽  
pp. 57-61 ◽  
Author(s):  
Yao Shi ◽  
Pei Zhang ◽  
Tuotuo Fang ◽  
Erhao Gao ◽  
Fujuan Xi ◽  
...  
Keyword(s):  
Water Vapor ◽  
High Temperature ◽  
Nh3 Scr ◽  
High Temperature Water ◽  
In Situ Regeneration ◽  
Scr Catalysts ◽  
Temperature Water

scholarly journals Barley (Hordeum vulgare) oxalate oxidase is a manganese-containing enzyme

1999 ◽  
Vol 343 (1) ◽  
pp. 185-190 ◽  
Author(s):  
Laura REQUENA ◽  
Stephen BORNEMANN
Keyword(s):  
Hordeum Vulgare ◽  
Epr Spectroscopy ◽  
Active Site ◽  
Homology Model ◽  
Direct Conversion ◽  
Oxalate Oxidase ◽  
Metal Analysis ◽  
Seedling Root

Oxalate oxidase (EC 1.2.3.4) catalyses the conversion of oxalate and dioxygen into CO2 and H2O2. The barley (Hordeum vulgare) seedling root enzyme was purified to homogeneity and shown by metal analysis and EPR spectroscopy to contain Mn(II) at up to 0.80 atom per subunit. The involvement of Mn and neither flavin, Cu nor Fe in the direct conversion of dioxygen to H2O2 makes oxalate oxidase unique. A model of the active site of the holoenzyme based on a homology model of the apoenzyme is proposed.

scholarly journals The Geometry of the Catalytic Active Site in [FeFe]-Hydrogenases is Determined by Hydrogen Bonding and Proton Transfer

2019 ◽  
Author(s):  
Jifu Duan ◽  
Stefan Mebs ◽  
Moritz Senger ◽  
Konstantin Laun ◽  
Florian Wittkamp ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Proton Transfer ◽  
Active Site ◽  
Time Resolved ◽  
X Ray Crystallography ◽  
Hydrogen Bonding Interactions ◽  
Catalytic Active Site ◽  
Catalytic Intermediates ◽  
Time Resolved Infrared Spectroscopy

The H2 conversion and CO inhibition reactivity of nine [FeFe]-hydrogenase constructs with semi-artificial cofactors was studied by in situ and time-resolved infrared spectroscopy, X-ray crystallography, and theoretical methods. Impaired hydrogen turnover and proton transfer as well as characteristic CO inhibition/ reactivation kinetics are assigned to varying degrees of hydrogen-bonding interactions at the active site. We show that the probability to adopt catalytic intermediates is modulated by intramolecular and protein-cofactor interactions that govern structural dynamics at the active site of [FeFe]-hydrogenases.<br>

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