Anion Inhibition Studies of the β-Class Carbonic Anhydrase CAS3 from the Filamentous Ascomycete Sordaria macrospora

CAS3 is a newly cloned cytosolic β-class carbonic anhydrase (CA, EC 4.2.1.1) from the filamentous ascomycete Sordaria macrospora. This enzyme has a high catalytic activity for the physiological CO2 hydration reaction and herein, we report the inhibition profile of CAS3 with anions and small molecules. The most effective CAS3 anions/small molecule inhibitors were diethyl-dithiocarbamate, sulfamide, sulfamate, phenyl boronic and phenyl arsonic acids, with KIs in the range of 0.89 mM–97 µM. Anions such as iodide, the pseudohalides, bicarbonate, carbonate, nitrate, nitrite, hydrogensulfide, stannate, selenate, tellurate, tetraborate, perrhenate, perruthenate, selenocyanide and trithiocarbonate were low millimolar CAS3 inhibitors. The light halides, sulfate, hydrogensulfite, peroxydisulfate, diphosphate, divanadate, perchlorate, tetrafluoroborate, fluorosulfonate and iminodisulfonate did not significantly inhibit this enzyme. These data may be useful for developing antifungals based on CA inhibition, considering the fact that many of the inhibitors reported here may be used as lead molecules and, by incorporating the appropriate organic scaffolds, potent nanomolar inhibitors could be developed.

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Sulfonamide Inhibition Studies of a New β-Carbonic Anhydrase from the Pathogenic Protozoan Entamoeba histolytica

International Journal of Molecular Sciences ◽

10.3390/ijms19123946 ◽

2018 ◽

Vol 19 (12) ◽

pp. 3946 ◽

Cited By ~ 4

Author(s):

Silvia Bua ◽

Susanna Haapanen ◽

Marianne Kuuslahti ◽

Seppo Parkkila ◽

Claudiu Supuran

Keyword(s):

Catalytic Activity ◽

Carbonic Anhydrase ◽

Entamoeba Histolytica ◽

Mechanisms Of Action ◽

Hydration Reaction ◽

Lead Compounds ◽

Inhibition Studies ◽

Pathogenic Protozoan

A newly described β-carbonic anhydrase (CA, EC 4.2.1.1) from the pathogenic protozoan Entamoeba histolytica, EhiCA, was recently shown to possess a significant catalytic activity for the physiologic CO2 hydration reaction (kcat of 6.7 × 105 s−1 and a kcat/Km of 8.9 × 107 M−1 s−1). A panel of sulphonamides and one sulfamate, some of which are clinically used drugs, were investigated for their inhibitory properties against EhiCA. The best inhibitors detected in the study were 4-hydroxymethyl/ethyl-benzenesulfonamide (KIs of 36–89 nM), whereas some sulfanilyl-sulfonamides showed activities in the range of 285–331 nM. Acetazolamide, methazolamide, ethoxzolamide, and dichlorophenamide were less effective inhibitors (KIs of 509–845 nM) compared to other sulfonamides investigated here. As β-CAs are not present in vertebrates, the present study may be useful for detecting lead compounds for the design of more effective inhibitors with potential to develop anti-infectives with alternative mechanisms of action.

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Sulfonamide Inhibition Studies of the β-Class Carbonic Anhydrase CAS3 from the Filamentous Ascomycete Sordaria macrospora

Molecules ◽

10.3390/molecules25051036 ◽

2020 ◽

Vol 25 (5) ◽

pp. 1036 ◽

Cited By ~ 1

Author(s):

Daniela Vullo ◽

Ronny Lehneck ◽

William A. Donald ◽

Stefanie Pöggeler ◽

Claudiu T. Supuran

Keyword(s):

Carbonic Anhydrase ◽

Model Organism ◽

The Other ◽

Antifungal Compounds ◽

Inhibition Study ◽

Sordaria Macrospora ◽

Filamentous Ascomycete ◽

Body Development ◽

Fruiting Body Development ◽

Inhibition Studies

A new β-class carbonic anhydrase was cloned and purified from the filamentous ascomycete Sordaria macrospora, CAS3. This enzyme has a higher catalytic activity compared to the other two such enzymes from this fungus, CAS1 and CAS2, which were reported earlier, with the following kinetic parameters: kcat of (7.9 ± 0.2) × 105 s−1, and kcat/Km of (9.5 ± 0.12) × 107 M−1∙s−1. An inhibition study with a panel of sulfonamides and one sulfamate was also performed. The most effective CAS3 inhibitors were benzolamide, brinzolamide, dichlorophnamide, methazolamide, acetazolamide, ethoxzolamide, sulfanilamide, methanilamide, and benzene-1,3-disulfonamide, with KIs in the range of 54–95 nM. CAS3 generally shows a higher affinity for this class of inhibitors compared to CAS1 and CAS2. As S. macrospora is a model organism for the study of fruiting body development in fungi, these data may be useful for developing antifungal compounds based on CA inhibition.

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Sulfonamide Inhibition Studies of an α-Carbonic Anhydrase from Schistosoma mansoni, a Platyhelminth Parasite Responsible for Schistosomiasis

International Journal of Molecular Sciences ◽

10.3390/ijms21051842 ◽

2020 ◽

Vol 21 (5) ◽

pp. 1842 ◽

Cited By ~ 3

Author(s):

Andrea Angeli ◽

Mariana Pinteala ◽

Stelian S. Maier ◽

Bogdan C. Simionescu ◽

Akram A. Da’dara ◽

...

Keyword(s):

Carbonic Anhydrase ◽

Schistosoma Mansoni ◽

Drug Target ◽

Hydration Reaction ◽

High Catalytic Activity ◽

Intestinal Schistosomiasis ◽

Host Parasite ◽

Inhibition Studies ◽

Platyhelminth Parasite ◽

Aromatic Heterocyclic

Schistosomiasis is a debilitating infection provoked by parasitic flatworms called schistosomes. The species Schistosoma mansoni is endemic in Africa, where it causes intestinal schistosomiasis. Recently, an α-carbonic anhydrase (CA, EC 4.2.1.1) was cloned and characterized from this organism and designated as SmCA. The protein is expressed in the tegument (skin) of S. mansoni at the host–parasite interface. Recombinant SmCA possesses high catalytic activity in the CO2 hydration reaction, similar to that of human CA isoform II with a kcat of 1.2 × 106 s−1 and a kcat/KM of 1.3 × 108 M−1·s−1. It has been found that schistosomes whose SmCA gene is suppressed using RNA interference are unable to establish a robust infection in mice, suggesting that the chemicals that inhibit SmCA function should have the same debilitating effect on the parasites. In this study, a collection of aromatic/heterocyclic sulfonamides were investigated as possible SmCA inhibitors. Several sulfonamides inhibited SmCA with medium to weak potency (KI values of 737.2 nM−9.25 μM), whereas some heterocyclic compounds inhibited the enzyme with KI values in the range of 124−325 nM. The α-CA from S. mansoni, SmCA, is proposed as a new anti-schistosomiasis drug target.

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Cloning, Characterization and Anion Inhibition Studies of a β-Carbonic Anhydrase from the Pathogenic Protozoan Entamoeba histolytica

Molecules ◽

10.3390/molecules23123112 ◽

2018 ◽

Vol 23 (12) ◽

pp. 3112 ◽

Cited By ~ 4

Author(s):

Susanna Haapanen ◽

Silvia Bua ◽

Marianne Kuuslahti ◽

Seppo Parkkila ◽

Claudiu Supuran

Keyword(s):

Catalytic Activity ◽

Carbonic Anhydrase ◽

Entamoeba Histolytica ◽

Enzyme Inhibitors ◽

Phenylboronic Acid ◽

Sulfamic Acid ◽

Hydration Reaction ◽

High Catalytic Activity ◽

Lead Compounds ◽

Pathogenic Protozoan

We report the cloning and catalytic activity of a β-carbonic anhydrase (CA, EC 4.2.1.1), isolated from the pathogenic protozoan Entamoeba histolytica, EhiCA. This enzyme has a high catalytic activity for the physiologic CO2 hydration reaction, with a kcat of 6.7 × 105 s−1 and a kcat/Km of 8.9 × 107 M−1 × s−1. An anion inhibition study of EhiCA with inorganic/organic anions and small molecules revealed that fluoride, chloride, cyanide, azide, pyrodiphosphate, perchlorate, tetrafluoroborate and sulfamic acid did not inhibit the enzyme activity, whereas pseudohalides (cyanate and thiocyanate), bicarbonate, nitrate, nitrite, diethyldithiocarbamate, and many complex inorganic anions showed inhibition in the millimolar range (KIs of 0.51–8.4 mM). The best EhiCA inhibitors were fluorosulfonate, sulfamide, phenylboronic acid and phenylarsonic acid (KIs in the range of 28–86 μM). Since β-CAs are not present in vertebrates, the present study may be useful for detecting lead compounds for the design of effective enzyme inhibitors, with potential to develop anti-infectives with alternative mechanisms of action.

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Solvent-Free Assembled Fe-Chitosan Chelates Derived N-Doped Carbon Layer-Encapsulated Fe/Fe3C for ORR and OER

NANO ◽

10.1142/s1793292020500708 ◽

2020 ◽

Vol 15 (06) ◽

pp. 2050070

Author(s):

Renxing Huang ◽

Ying Lei ◽

Dandan Zhang ◽

Huaming Xie ◽

Xingyong Liu ◽

...

Keyword(s):

Catalytic Activity ◽

Transition Metal ◽

Nitrogen Source ◽

Small Molecule ◽

Carbon Layer ◽

Transition Metal Catalysts ◽

Solvent Free ◽

Metal Catalyst ◽

High Peak Power ◽

High Catalytic Activity

Carbon encapsulated transition metal catalysts receive extensive attention in electrochemical catalytic oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) due to the unique structure and highly adjustable electronic configuration. Herein, we synthesized 3D porous Active-N-rich graphene-like carbon layer-encapsulated Fe/Fe3C (Fe@NCG) via pyrolysis of a mixture of solvent-free assembled Fe-chitosan chelates and additional small molecule nitrogen source urea, wherein space-confinement effect of chelates suppressed agglomeration of [Formula: see text] ions and small molecule nitrogen source facilitated regulation of N configurations. The optimized catalyst Fe@NCG shows remarkable ORR/OER bifunctional catalytic activity with a half-wave potential of 0.86 V for ORR and a moderate potential difference of 0.85 V in alkaline medium. Comparative studies revealed that Active-N-rich carbon layer and inner well-dispersed Fe/Fe3C nanoparticles and the favorable interface structures between them were responsible for high catalytic activity. Excitingly, the assembled zinc-air battery with Fe@NCG catalysts exhibits a high open-circuit potential (1.45 V), extremely high peak power density (204.50[Formula: see text][Formula: see text] and energy density (814.70[Formula: see text]Wh[Formula: see text][Formula: see text]) as well as robust charge–discharge durability, surpassing those of noble metal catalyst. This proposed simple and universal strategy can also be extended to synthesize carbon encapsulated other transition metal electrocatalysts.

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Enhanced catalytic activity of low-Pt content nanocatalysts supported on hollow carbon spheres for the ORR in alkaline media

MRS Advances ◽

10.1557/adv.2020.370 ◽

2020 ◽

Vol 5 (57-58) ◽

pp. 2961-2972

Author(s):

P.C. Meléndez-González ◽

E. Garza-Duran ◽

J.C. Martínez-Loyola ◽

P. Quintana-Owen ◽

I.L. Alonso-Lemus ◽

...

Keyword(s):

Catalytic Activity ◽

Anion Exchange ◽

Average Particle Size ◽

Synthesis Method ◽

Alkaline Media ◽

High Catalytic Activity ◽

Average Particle ◽

Carbon Spheres ◽

Hollow Carbon ◽

Hollow Carbon Spheres

In this work, low-Pt content nanocatalysts (≈ 5 wt. %) supported on Hollow Carbon Spheres (HCS) were synthesized by two routes: i) colloidal conventional polyol, and ii) surfactant-free Bromide Anion Exchange (BAE). The nanocatalysts were labelled as Pt/HCS-P and Pt/HCS-B for polyol and BAE, respectively. The physicochemical characterization of the nanocatalysts showed that by following both methods, a good control of chemical composition was achieved, obtaining in addition well dispersed nanoparticles of less than 3 nm TEM average particle size (d) on the HCS. Pt/HCS-B contained more Pt0 species than Pt/HCS-P, an effect of the synthesis method. In addition, the structure of the HCS remains more ordered after BAE synthesis, compared to polyol. Regarding the catalytic activity for the Oxygen Reduction Reaction (ORR) in 0.5 M KOH, Pt/HCS-P and Pt/HCS-B showed a similar performance in terms of current density (j) at 0.9 V vs. RHE than the benchmark commercial 20 wt. % Pt/C. However, Pt/HCS-P and Pt/HCS-B demonstrated a 6 and 5-fold increase in mass catalytic activity compared to Pt/C, respectively. A positive effect of the high specific surface area of the HCS and its interactions with metal nanoparticles and electrolyte, which promoted the mass transfer, increased the performance of Pt/HCS-P and Pt/HCS-B. The high catalytic activity showed by Pt/HCS-B and Pt/HCS-P for the ORR, even with a low-Pt content, make them promising cathode nanocatalysts for Anion Exchange Membrane Fuel Cells (AEMFC).

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Ordered Intermetallic Nanoparticles with High Catalytic Activity Prepared by an Electrochemically Induced Phase Transformation

10.26434/chemrxiv.8289812 ◽

2019 ◽

Author(s):

Du Sun ◽

yunfei wang ◽

Kenneth Livi ◽

chuhong wang ◽

ruichun luo ◽

...

Keyword(s):

Catalytic Activity ◽

Diffusion Mechanism ◽

Reduction Reaction ◽

Atomic Scale ◽

High Catalytic Activity ◽

Ambient Conditions ◽

Magnetic Devices ◽

Disordered Alloys ◽

Ordered Intermetallic ◽

Intermetallic Nanoparticles

<div> The synthesis of alloys with long range atomic scale ordering (ordered intermetallics) is an emerging field of nanochemistry. Ordered intermetallic nanoparticles are useful for a wide variety of applications such as catalysis, superconductors, and magnetic devices. However, the preparation of nanostructured ordered intermetallics is challenging in comparison to disordered alloys, hindering progress in materials development. We report a process for converting colloidally synthesized ordered intermetallic PdBi2 to ordered intermetallic Pd3Bi nanoparticles under ambient conditions by an electrochemically induced phase transition. The low melting point of PdBi2 corresponds to low vacancy formation energies which enables the facile removal of the Bi from the surface, while simultaneously enabling interdiffusion of the constituent atoms via a vacancy diffusion mechanism under ambient conditions. The resulting phase-converted ordered intermetallic Pd3Bi exhibits 11x and 3.5x higher mass activty and high methanol tolerance for the oxygen reduction reaction compared to Pt/C and Pd/C, respectively,which is the highest reported for a Pd-based catalyst, to the best of our knowledge. These results establish a key development in the synthesis of noble metal rich ordered intermetallic phases with high catalytic activity, and sets forth guidelines for the design of ordered intermetallic compounds under ambient conditions. </div>

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Nickel (II) and oxovanadium (IV) complexes supported on MCM-41 mesoporous and their application in catalytic selective sulfide and thiol oxidation

Combinatorial Chemistry & High Throughput Screening ◽

10.2174/1386207323999201111192649 ◽

2020 ◽

Vol 23 ◽

Author(s):

Mohsen Nikoorazm ◽

Maryam Khanmoradi ◽

Masoumeh Sayadian

Keyword(s):

Catalytic Activity ◽

Room Temperature ◽

Sol Gel ◽

Reaction Times ◽

Significant Loss ◽

Spectral Studies ◽

High Catalytic Activity ◽

Catalytic Systems ◽

Solvent Free Conditions ◽

Mcm 41

Introduction:: MCM-41 was synthesized using the sol-gel method. Then two new transition metal complexes of Nickel (II) and Vanadium (IV), were synthesized by immobilization of adenine (6-aminopurine) into MCM-41 mesoporous. The compounds have been characterized by XRD, TGA, SEM, AAS and FT-IR spectral studies. Using these catalysts provided an efficient and enantioselective procedure for oxidation of sulfides to sulfoxides and oxidative coupling of thiols to their corresponding disulfides using hydrogen peroxide at room temperature. Materials and Methods:: To a solution of sulfide or thiol (1 mmol) and H2O2 (5 mmol), a determined amount of the catalyst was added. The reaction mixture was stirred at room temperature for the specific time under solvent free conditions. The progress of the reaction was monitored by TLC using n-hexane: acetone (8:2). Afterwards, the catalyst was removed from the reaction mixture by centrifugation and, then, washed with dichloromethane in order to give the pure products. Results:: All the products were obtained in excellent yields and short reaction times indicating the high activity of the synthesized catalysts. Besides, the catalysts can be recovered and reused for several runs without significant loss in their catalytic activity. Conclusion:: These catalytic systems furnish the products very quickly with excellent yields and VO-6AP-MCM-41 shows high catalytic activity compared to Ni-6AP-MCM-41.

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Mechanisms of methane decomposition and carbon species oxidation on the Pr0.42Sr0.6Co0.2Fe0.7Nb0.1O3−σ electrode with high catalytic activity

Journal of Materials Chemistry A ◽

10.1039/c5ta07599h ◽

2015 ◽

Vol 3 (45) ◽

pp. 22816-22823 ◽

Cited By ~ 5

Author(s):

Peng Zhang ◽

Guoqing Guan ◽

Deni S. Khaerudini ◽

Xiaogang Hao ◽

Chunfeng Xue ◽

...

Keyword(s):

Catalytic Activity ◽

Carbon Deposition ◽

Methane Decomposition ◽

High Catalytic Activity ◽

Carbon Species

Carbon deposition characteristics on PSCFN and Ni–YSZ due to thermal CH4 decomposition are investigated by using TPR technique.

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Bio-Derived Catalysts: A Current Trend of Catalysts Used in Biodiesel Production

Catalysts ◽

10.3390/catal11070812 ◽

2021 ◽

Vol 11 (7) ◽

pp. 812

Author(s):

Hoang Chinh Nguyen ◽

My-Linh Nguyen ◽

Chia-Hung Su ◽

Hwai Chyuan Ong ◽

Horng-Yi Juan ◽

...

Keyword(s):

Catalytic Activity ◽

Fossil Fuels ◽

Current Trend ◽

Biodiesel Production ◽

High Catalytic Activity ◽

Promising Alternative ◽

Advantages And Disadvantages ◽

Biodiesel Synthesis ◽

Alkali Catalysts ◽

A Current

Biodiesel is a promising alternative to fossil fuels and mainly produced from oils/fat through the (trans)esterification process. To enhance the reaction efficiency and simplify the production process, various catalysts have been introduced for biodiesel synthesis. Recently, the use of bio-derived catalysts has attracted more interest due to their high catalytic activity and ecofriendly properties. These catalysts include alkali catalysts, acid catalysts, and enzymes (biocatalysts), which are (bio)synthesized from various natural sources. This review summarizes the latest findings on these bio-derived catalysts, as well as their source and catalytic activity. The advantages and disadvantages of these catalysts are also discussed. These bio-based catalysts show a promising future and can be further used as a renewable catalyst for sustainable biodiesel production.

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