Role of carboxylic acid groups in the reduction of nitric oxide by carbon at low temperature, as exemplified by graphene oxide

2017 ◽  
Vol 19 (33) ◽  
pp. 22462-22471 ◽  
Author(s):  
J. Zhang ◽  
Q. Gao ◽  
X. M. Li ◽  
J. Z. Zhou ◽  
X. X. Ruan ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Graphene Oxide ◽  
Carboxylic Acid ◽  
Low Temperature ◽  
Active Sites ◽  
Reduction Of No ◽  
Carboxylic Acid Groups ◽  
Nano Carbon ◽  
First Time

This work reported the reduction of NO by carboxylic acid groups and the derived active sites on nano-carbon at a temperature as low as 100 °C for the first time.

scholarly journals Insights into the promotion role of phosphorus doping on carbon as a metal-free catalyst for low-temperature selective catalytic reduction of NO with NH3

RSC Advances ◽  
2020 ◽  
Vol 10 (22) ◽  
pp. 12908-12919
Author(s):  
Weifeng Li ◽  
Shuangling Jin ◽  
Rui Zhang ◽  
Yabin Wei ◽  
Jiangcan Wang ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Low Temperature ◽  
Selective Catalytic Reduction ◽  
No Reduction ◽  
Catalytic Reduction ◽  
Carbon Aerogels ◽  
Phosphorus Doping ◽  
Reduction Of No ◽  
Metal Free

P species can effectively enhance the catalytic activity of carbon aerogels for NO reduction at low temperature.

scholarly journals Revealing the unknown aspects of initial steps of prenylated flavin mononucleotide biosynthesis – the role of Lys129 in PaUbiX

2021 ◽  
Author(s):  
Szymon Zaczek ◽  
Agnieszka Dybala-Defratyka
Keyword(s):  
Active Sites ◽  
Laboratory Experiments ◽  
Phosphate Group ◽  
Flavin Mononucleotide ◽  
Dipolar Cycloaddition ◽  
Quantum Mechanical ◽  
Constant Ph ◽  
First Time ◽  
Simulation Time

Background Prenylated flavin mononucleotide (prFMN) is a recently discovered, heavily modified flavin compound. It is the only known cofactor that enables enzymatic 1,3-dipolar cycloaddition reactions. It is produced by enzymes from UbiX family, from flavin mononucleotide and either dimethylallyl mono- or diphosphate. prFMN biosynthesis is currently reported to be initiated by a protonation of the substrate by Glu140. Methods Computational chemistry methods are applied herein - mostly different flavors of molecular dynamics MD, such as Constant pH MD, hybrid Quantum-Mechanical / Molecular Mechanical MD, and classical MD. Results Glu140 competes for a single proton with Lys129 but it is the latter that adopted a protonated state throughout most of the simulation time. Lys129 plays a key role in the positioning of the DMAP’s phosphate group within the PaUbiX active site. DMAP’s breakdown into a phosphate and a prenyl group can be decoupled from the protona-tion of the DMAP’s phosphate group. Conclusions The role of Lys129 in functioning of PaUbiX is reported for the first time. The severity of interactions between Glu140, Lys129, and DMAP’s phosphate group enables an unusual decoupling of phosphate’s protonation from DMAP’s breakdown. Those findings are most likely conserved throughout the UbiX family to the structural re-semblence of active sites of those proteins. Significance Mechanistic insights into a crucial biochemical process, biosynthesis of prFMN, are provided. This study, alt-hough purely computational, extends and perfectly complements the knowledge obtained in classical laboratory experiments.

Metal organic frameworks decorated with free carboxylic acid groups: topology, metal capture and dye adsorption properties

2020 ◽  
Vol 49 (41) ◽  
pp. 14690-14705
Author(s):  
M. Naqi Ahamad ◽  
M. Shahnawaz Khan ◽  
M. Shahid ◽  
Musheer Ahmad
Keyword(s):  
Carboxylic Acid ◽  
Metal Organic Frameworks ◽  
Dye Adsorption ◽  
Adsorption Properties ◽  
Carboxylic Acid Groups ◽  
Metal Capture ◽  
Metal Organic

Elaborating the role of uncoordinated carboxylic acid functions in MOFs in post synthetic modification (PSM) through metal capture and hence in tuning dye adsorption properties.

Exposed metal oxide active sites on mesoporous titania channels: a promising design for low-temperature selective catalytic reduction of NO with NH3

2018 ◽  
Vol 54 (30) ◽  
pp. 3783-3786 ◽  
Author(s):  
Jianwei Fan ◽  
Menghua Lv ◽  
Wei Luo ◽  
Xianqiang Ran ◽  
Yonghui Deng ◽  
...  
Keyword(s):  
Low Temperature ◽  
Metal Oxide ◽  
Selective Catalytic Reduction ◽  
Active Sites ◽  
Catalytic Reduction ◽  
Mesoporous Titania ◽  
Active Centers ◽  
Reduction Of No ◽  
Low Temperature Scr

A subtle catalyst is designed with CuO and MnO2 active centers on the surface of mesoporous titania for low-temperature SCR.

scholarly journals Astrovirus-Induced Synthesis of Nitric Oxide Contributes to Virus Control during Infection

2004 ◽  
Vol 78 (3) ◽  
pp. 1564-1574 ◽  
Author(s):  
Matthew D. Koci ◽  
Laura A. Kelley ◽  
Diane Larsen ◽  
Stacey Schultz-Cherry
Keyword(s):  
Nitric Oxide ◽  
Ex Vivo ◽  
Small Animal ◽  
Innate Immune Responses ◽  
Vitro Analysis ◽  
Oxide Synthase ◽  
First Time

ABSTRACT Astrovirus is one of the major causes of infant and childhood diarrhea worldwide. Our understanding of astrovirus pathogenesis trails behind our knowledge of its molecular and epidemiologic properties. Using a recently developed small-animal model, we investigated the mechanisms by which astrovirus induces diarrhea and the role of both the adaptive and innate immune responses to turkey astrovirus type-2 (TAstV-2) infection. Astrovirus-infected animals were analyzed for changes in total lymphocyte populations, alterations in CD4+/CD8+ ratios, production of virus-specific antibodies (Abs), and macrophage activation. There were no changes in the numbers of circulating or splenic lymphocytes or in CD4+/CD8+ ratios compared to controls. Additionally, there was only a modest production of virus-specific Abs. However, adherent spleen cells from infected animals produced more nitric oxide (NO) in response to ex vivo stimulation with lipopolysaccharide. In vitro analysis demonstrated that TAstV-2 induced macrophage production of inducible nitric oxide synthase. Studies using NO donors and inhibitors in vivo demonstrated, for the first time, that NO inhibited astrovirus replication. These studies suggest that NO is important in limiting astrovirus replication and are the first, to our knowledge, to describe the potential role of innate immunity in astrovirus infection.

Renal arginine and protein synthesis are increased during early endotoxemia in mice

2002 ◽  
Vol 282 (2) ◽  
pp. F316-F323 ◽  
Author(s):  
Marcella M. Hallemeesch ◽  
Peter B. Soeters ◽  
Nicolaas E. P. Deutz
Keyword(s):  
Nitric Oxide ◽  
Protein Synthesis ◽  
Protein Metabolism ◽  
De Novo ◽  
Early Response ◽  
No Production ◽  
Arginine Metabolism ◽  
First Time ◽  
Adaptive Role

The kidney has an important function in arginine metabolism, because the kidney is the main endogenous source for de novo arginine production from circulating citrulline. In conditions such as sepsis, nitric oxide (NO) production is increased and is dependent on extracellular arginine availability. To elucidate the adaptive role of renal de novo arginine synthesis in a condition of increased NO production, we studied renal arginine metabolism in a mouse model of endotoxemia. Because arginine flux is largely dependent on protein flux, we also measured protein metabolism in mice. Female mice were injected intraperitoneally with lipopolysaccharide; control mice received 0.9% NaCl. Six hours later, renal blood flow was measured with the use of para-aminohippuric acid. Arginine and protein metabolism were studied using organ-balance, stable-isotope techniques. Systemic NO production was increased in the endotoxin-treated mice. In addition, renal protein synthesis and de novo arginine production from citrulline were increased. However, no effect on renal NO production was observed. In conclusion, increased renal de novo arginine production may serve to sustain systemic NO production. To our knowledge, it was shown for the first time that renal protein synthesis is enhanced in the early response to endotoxemia.

scholarly journals Nitric oxide rapidly scavenges tyrosine and tryptophan radicals

1995 ◽  
Vol 310 (3) ◽  
pp. 745-749 ◽  
Author(s):  
J P Eiserich ◽  
J Butler ◽  
A van der Vliet ◽  
C E Cross ◽  
B Halliwell
Keyword(s):  
Nitric Oxide ◽  
Biologically Relevant ◽  
Tyrosine Residues ◽  
Transfer Processes ◽  
Diffusion Controlled ◽  
Electron Transfer Processes ◽  
Protein Radicals ◽  
First Time

By utilizing a pulse-radiolytic technique, we demonstrate for the first time that the rate constant for the reaction of nitric oxide (.NO) with biologically relevant tyrosine and tryptophan radicals (Tyr. and Trp. respectively) in amino acids, peptides and proteins is of the order of (1-2) x 10(9) M-1.s-1. We also show that .NO effectively interferes with electron-transfer processes between tryptophan and tyrosine residues in proteins subjected to pulse radiolysis. The near diffusion-controlled rates of these reactions, coupled with the increasingly recognized role of protein radicals in enzyme catalysis and oxidative damage, suggest that Tyr. and Trp. are likely and important targets for .NO generated in vivo.

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