Effect of carbonic anhydrase on enzymatic conversion of CO2 to formic acid and optimization of reaction conditions

2015 ◽  
Vol 116 ◽  
pp. 89-94 ◽  
Author(s):  
Yanzi Wang ◽  
Manfeng Li ◽  
Zhiping Zhao ◽  
Wenfang Liu
Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2248
Author(s):  
Lukáš Petera ◽  
Klaudia Mrazikova ◽  
Lukas Nejdl ◽  
Kristyna Zemankova ◽  
Marketa Vaculovicova ◽  
...  

Synthesis of RNA nucleobases from formamide is one of the recurring topics of prebiotic chemistry research. Earlier reports suggest that thymine, the substitute for uracil in DNA, may also be synthesized from formamide in the presence of catalysts enabling conversion of formamide to formaldehyde. In the current paper, we show that to a lesser extent conversion of uracil to thymine may occur even in the absence of catalysts. This is enabled by the presence of formic acid in the reaction mixture that forms as the hydrolysis product of formamide. Under the reaction conditions of our study, the disproportionation of formic acid may produce formaldehyde that hydroxymethylates uracil in the first step of the conversion process. The experiments are supplemented by quantum chemical modeling of the reaction pathway, supporting the plausibility of the mechanism suggested by Saladino and coworkers.


Molecules ◽  
2018 ◽  
Vol 24 (1) ◽  
pp. 23 ◽  
Author(s):  
Kuo-Ting Chen ◽  
Kevin Nguyen ◽  
Christian Ieritano ◽  
Feng Gao ◽  
Yann Seimbille

We herein describe a flexible synthesis of a small library of 68Ga-labeled CAIX-targeted molecules via an orthogonal 2-cyanobenzothiazole (CBT)/1,2-aminothiol click reaction. Three novel CBT-functionalized chelators (1–3) were successfully synthesized and labeled with the positron emitter gallium-68. Cross-ligation between the pre-labeled bifunctional chelators (BFCs) and the 1,2-aminothiol-acetazolamide derivatives (8 and 9) yielded six new 68Ga-labeled CAIX ligands with high radiochemical yields. The click reaction conditions were optimized to improve the reaction rate for applications with short half-life radionuclides. Overall, our methodology allows for a simple and efficient radiosynthetic route to produce a variety of 68Ga-labeled imaging agents for tumor hypoxia.


Author(s):  
Mehdi Ashraf-Khorassani ◽  
William M. Coleman ◽  
Michael F. Dube ◽  
Larry T. Taylor

SummaryFree amino acids have been isolated via optimized enzymatic hydrolysis of F1 tobacco protein using two cationic resins (Amberlite IR120 and Dowex MAC-2). Optimized enzymatic conversions of the protein as a result of systematic variations in conditions (e.g., time, temperature, pH, enzyme type, enzyme concentration, anaerobic/aerobic environments, and protein concentration) employing commercially available enzymes, were consistently higher than 50% with qualitative amino acid arrays that were consistent with the known composition of tobacco F1 protein. Amberlite IR120 was shown to have a much higher efficiency and capacity for isolation of amino acids from standard solutions and from hydrolysate when compared with the results using Dowex MAC-2. Two columns packed with conditioned Amberlite IR120 (120 × 10 mm,12–15 g resin) and (200 × 25.4 mm, 60–65 g resin) were used to isolate two batches (2.5–3.0 mg and 13–15 mg) of free amino acids, respectively. A relatively inexpensive analytical methodology was developed for rapid analysis of the free amino acids contained within the enzyme hydrolysate. Commercially available enzymes, when employed in optimized reaction conditions, are very effective for enzymatic conversion of tobacco F1 protein to free amino acids.


1990 ◽  
Vol 68 (11) ◽  
pp. 2119-2121 ◽  
Author(s):  
Oswald S. Tee ◽  
Bushra Javed ◽  
Susan R. Mikkelsen

α-Cyclodextrin (CD) modestly increases the rate of oxidation of formic acid by bromine. The variation of rate constants with [Br−] is consistent with dominance of the formation of a CD•Br3− complex in determining the fraction of free Br2 and the CD•Br2 complex, under the reaction conditions. Potentiometric measurements support a dissociation constant of about 0.2 mM for the CD•Br3− complex, in agreement with an earlier spectrophotometric value. Analysis of the rate increases with [CD] implies that CD•Br2 is more reactive (~10 times) than free Br2 towards formate ion, as was found for phenols. These conclusions differ from those of another recent study. Keywords: catalysis, α-cyclodextrin, oxidation, formic acid, bromine.


2014 ◽  
Vol 20 (26) ◽  
pp. 7878-7883 ◽  
Author(s):  
Iván Sorribes ◽  
Kathrin Junge ◽  
Matthias Beller

ChemInform ◽  
2014 ◽  
Vol 46 (2) ◽  
pp. no-no
Author(s):  
Ivan Sorribes ◽  
Kathrin Junge ◽  
Matthias Beller

2021 ◽  
Vol 08 ◽  
Author(s):  
Suzanne Chayya ◽  
Mohammad H. El-Dakdouki ◽  
Akram Hijazi ◽  
Ghassan Younes ◽  
Ghassan Ibrahim ◽  
...  

Background: Transfer hydrogenation methods that employ non-H2 hydrogen sources have evolved as an attractive alternative for conventional hydrogenation approaches. Objective: In this study, we aimed at developing optimized conditions to induce the selective transfer hydrogenation reduction of aromatic alkynes catalyzed by PdCl2(PPh3)2 and using formic acid as the hydride source. Methods: The effect of various reaction parameters, such as the nature and amount of the catalyst, the H-donor/base couple, reaction time and temperature, and the nature of the solvent on the outcome of the alkyne reduction were investigated. Results: The reduction of the alkyne can be chemoselectively controlled by adjusting the reaction conditions. Among the tested catalysts, PdCl2(PPh3)2 was the most suitable with 2% of the catalyst being the optimal amount. While the reduction was successful in different solvents of different polarities, THF was selected as the solvent of choice. The reduction of diphenylacetylene yielded the alkene both at 50oC and 80oC. When testing the optimized conditions on the reduction of 4-phenyl-3-butyne-2-one, quantitative partial reduction to the corresponding α,β-unsaturated ketone was obtained at 50oC, while the saturated ketone was produced as the major product at 80oC. Conclusion: The chemoselective reduction of aromatic alkynes was performed successfully with complete conversion using 2% PdCl2(PPh3)2 as a catalyst, formic acid/NEt3 as the H-donor/base couple, THF as the solvent, at 50oC and 80oC.


2021 ◽  
Vol 52 ◽  
pp. 101679
Author(s):  
Zhibo Zhang ◽  
Tudor Vasiliu ◽  
Fangfang Li ◽  
Aatto Laaksonen ◽  
Francesca Mocci ◽  
...  

2019 ◽  
Author(s):  
Matthew M. Cerda ◽  
Jenna L. Mancuso ◽  
Emma J. Mullen ◽  
Christopher H. Hendon ◽  
Michael Pluth

<p>The enzymatic conversion of carbonyl sulfide (COS) to hydrogen sulfide (H<sub>2</sub>S) by carbonic anhydrase has been used to develop self-immolating thiocarbamates as COS-based H<sub>2</sub>S donors to further elucidate the impact of reactive sulfur species in biology. The high modularity of this approach has provided a library of COS-based H<sub>2</sub>S donors that can be activated by specific stimuli. A common limitation, however, is that many such donors result in the intermediate formation of an electrophilic quinone methide byproduct during donor activation. As a mild alternative, we demonstrate here that dithiasuccinoyl groups can function as COS/H<sub>2</sub>S donor motifs and that these groups release two equivalents of COS/H<sub>2</sub>S and uncage an amine payload under physiologically relevant conditions. Additionally, we demonstrate that COS/H<sub>2</sub>S release from this donor motif can be altered by electronic modulation and alkyl substitution. These insights are further supported by DFT investigations, which reveal that aryl and alkyl thiocarbamates release COS with significantly different activation energies.</p>


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