Articles de revues : « Carboni Anhydrases »

1

Sültemeyer, Dieter. « Carbonic anhydrase in eukaryotic algae : characterization, regulation, and possible function during photosynthesis ». Canadian Journal of Botany 76, n^o 6 (1 juin 1998) : 962–72. http://dx.doi.org/10.1139/b98-082.

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Carbonic anhydrase (CA) speeds up the equilibrium between CO2 and HCO3- at physiological pH values and has been detected in almost every species of the animal and plant kingdoms. Among eucaryotic micro- and macro-algae the enzyme is widely distributed and plays an important role in photosynthetic CO2 fixation. In some cases, different forms of carbonic anhydrases located extracellularly and intracellularly have been found to occur in the same cell. The expression of the genes encoding these CA isoforms are under the control of the inorganic carbon concentration in the medium, as the activities increase with decreasing the inorganic carbon content. Considerable progress has been made in recent years in isolating and characterizing the various forms of carbonic anhydrases on a biochemical and molecular level. Most of the data have been collected for microalgae like Chlamydomonas reinhardtii (Dangeard), while the situation in macroalgae is still descriptive. Therefore, this review summarizes the recent development with an emphasis on microalgae carbonic anhydrases.Key words: carbonic anhydrase, CO2 concentrating mechanism, macroalgae, microalgae, photosynthesis.

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Ignatova, Lyudmila, Natalia Rudenko, Elena Zhurikova, Maria Borisova-Mubarakshina et Boris Ivanov. « Carbonic Anhydrases in Photosynthesizing Cells of C3 Higher Plants ». Metabolites 9, n^o 4 (16 avril 2019) : 73. http://dx.doi.org/10.3390/metabo9040073.

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The review presents data on the location, nature, properties, number, and expression of carbonic anhydrase genes in the photosynthesizing cells of C3 plants. The available data about the presence of carbonic anhydrases in plasma membrane, cytoplasm, mitochondria, chloroplast stroma and thylakoids are scrutinized. Special attention was paid to the presence of carbonic anhydrase activities in the different parts of thylakoids, and on collation of sources of these activities with enzymes encoded by the established genes of carbonic anhydrases. The data are presented to show that the consistent incorporation of carbonic anhydrases belonging to different families of these enzymes forms a coherent system of CO2 molecules transport from air to chloroplasts in photosynthesizing cells, where they are included in organic molecules in the carboxylation reaction. It is discussed that the manifestation of the activity of a certain carbonic anhydrase depends on environmental conditions and the stage of ontogenesis.

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Wani, Tanvi V., et Mrunmayee P. Toraskar. « QSAR STUDIES ON HUMAN CARBONIC ANHYDRASE II INHIBITORS ». INDIAN DRUGS 58, n^o 11 (28 décembre 2021) : 18–28. http://dx.doi.org/10.53879/id.58.11.12350.

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Carbonic anhydrase II is one of the forms of human α carbonic anhydrases which are ubiquitous metalloenzymes that catalyze inter-conversion of carbon dioxide and water to bicarbonate and proton, overexpression of which leads to disorders such as glaucoma. 2D and 3D Quantitative Structure Activity Relationship studies were carried out on previously synthesized series of sulfanilamide derivatives by VLife MDS software using stepwise variable, multi-linear regression and k-nearest neighbor molecular field analysis methods. 2D-QSAR model depicts contribution of halogens (such as chlorine and fluorine), methylene and oxygen atoms to inhibition of human carbonic anhydrases II activity. Using k-nearest neighbor molecular field analysis method two 3D-QSAR models (model A and B) were generated from which model A was found to be the best validated model with q2 (0.9494), pred_r2 (0.7367) and q2 _ se (0.2037). It displayed the fact that the inhibitory action of sulfanilamide derivatives against human carbonic anhydrases II is influenced by hydrophobicity and electro positivity.

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Somalinga, Vijayakumar, Hannah Klemmer, Ashikha Arun, Stephanie Mathews, Hannah Wapshott et Amy M. Grunden. « Cloning, Over-Expression, and Purification of Carbonic Anhydrase from an Extremophilic Bacterium : An Introduction to Advanced Molecular Biology ». American Biology Teacher 80, n^o 1 (1 janvier 2018) : 29–34. http://dx.doi.org/10.1525/abt.2018.80.1.29.

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The photosynthetic bioreactor research program is a training platform appropriate for introducing advanced molecular biology techniques to undergraduate students and advanced high school biology students. For this advanced molecular biology training exercise, the enzyme carbonic anhydrase was cloned, over-expressed, purified, and functionally characterized. Carbonic anhydrases are industrially important enzymes with potential use in carbon sequestration and biofuel production. Alpha and beta carbonic anhydrases from Photobacterium profundum, a psychrophilic, halotolerant bacterium, were characterized in this study. Carbonic anhydrases that can withstand high salinity and are active at low temperatures can be transformed into oleaginous marine microalgae to enhance biofuel production. Our research program started with a three-day boot camp with lectures in relevant topics of molecular biology, microbiology, and research methods. After the boot camp, the lab phase of the project involved training students to perform polymerase chain reaction, DNA gel electrophoresis, DNA ligation, and bacterial transformation. In the final phase of the project, students were trained in recombinant protein over-expression and protein purification techniques. Here we report successful cloning and over-expression by high school students of two novel carbonic anhydrases from a psychrohalophile with application in biofuel production.

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Tomar, Jyoti Singh, et Jun Shen. « Characterization of Carbonic Anhydrase In Vivo Using Magnetic Resonance Spectroscopy ». International Journal of Molecular Sciences 21, n^o 7 (1 avril 2020) : 2442. http://dx.doi.org/10.3390/ijms21072442.

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Carbonic anhydrase is a ubiquitous metalloenzyme that catalyzes the reversible interconversion of CO2/HCO3−. Equilibrium of these species is maintained by the action of carbonic anhydrase. Recent advances in magnetic resonance spectroscopy have allowed, for the first time, in vivo characterization of carbonic anhydrase in the human brain. In this article, we review the theories and techniques of in vivo 13C magnetization (saturation) transfer magnetic resonance spectroscopy as they are applied to measuring the rate of exchange between CO2 and HCO3− catalyzed by carbonic anhydrase. Inhibitors of carbonic anhydrase have a wide range of therapeutic applications. Role of carbonic anhydrases and their inhibitors in many diseases are also reviewed to illustrate future applications of in vivo carbonic anhydrase assessment by magnetic resonance spectroscopy.

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Rasmussen, Jacob K., et Ebbe Boedtkjer. « Carbonic anhydrase inhibitors modify intracellular pH transients and contractions of rat middle cerebral arteries during CO2/HCO3– fluctuations ». Journal of Cerebral Blood Flow & ; Metabolism 38, n^o 3 (20 mars 2017) : 492–505. http://dx.doi.org/10.1177/0271678x17699224.

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The CO2/HCO3– buffer minimizes pH changes in response to acid–base loads, HCO3– provides substrate for Na+,HCO3–-cotransporters and Cl–/HCO3–-exchangers, and H+ and HCO3– modify vasomotor responses during acid–base disturbances. We show here that rat middle cerebral arteries express cytosolic, mitochondrial, extracellular, and secreted carbonic anhydrase isoforms that catalyze equilibration of the CO2/HCO3– buffer. Switching from CO2/HCO3–-free to CO2/HCO3–-containing extracellular solution results in initial intracellular acidification due to hydration of CO2 followed by gradual alkalinization due to cellular HCO3– uptake. Carbonic anhydrase inhibition decelerates the initial acidification and attenuates the associated transient vasoconstriction without affecting intracellular pH or artery tone at steady-state. Na+,HCO3–-cotransport and Na+/H+-exchange activity after NH4+-prepulse-induced intracellular acidification are unaffected by carbonic anhydrase inhibition. Extracellular surface pH transients induced by transmembrane NH3 flux are evident under CO2/HCO3–-free conditions but absent when the buffer capacity and apparent H+ mobility increase in the presence of CO2/HCO3– even after the inhibition of carbonic anhydrases. We conclude that (a) intracellular carbonic anhydrase activity accentuates pH transients and vasoconstriction in response to acute elevations of pCO2, (b) CO2/HCO3– minimizes extracellular surface pH transients without requiring carbonic anhydrase activity, and (c) carbonic anhydrases are not rate limiting for acid–base transport across cell membranes during recovery from intracellular acidification.

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Smith, Kerry S., et James G. Ferry. « A Plant-Type (β-Class) Carbonic Anhydrase in the Thermophilic Methanoarchaeon Methanobacterium thermoautotrophicum ». Journal of Bacteriology 181, n^o 20 (15 octobre 1999) : 6247–53. http://dx.doi.org/10.1128/jb.181.20.6247-6253.1999.

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ABSTRACT Carbonic anhydrase, a zinc enzyme catalyzing the interconversion of carbon dioxide and bicarbonate, is nearly ubiquitous in the tissues of highly evolved eukaryotes. Here we report on the first known plant-type (β-class) carbonic anhydrase in the archaea. TheMethanobacterium thermoautotrophicum ΔH cabgene was hyperexpressed in Escherichia coli, and the heterologously produced protein was purified 13-fold to apparent homogeneity. The enzyme, designated Cab, is thermostable at temperatures up to 75°C. No esterase activity was detected withp-phenylacetate as the substrate. The enzyme is an apparent tetramer containing approximately one zinc per subunit, as determined by plasma emission spectroscopy. Cab has a CO2 hydration activity with a k cat of 1.7 × 104 s−1 and Km for CO2 of 2.9 mM at pH 8.5 and 25°C. Western blot analysis indicates that Cab (β class) is expressed in M. thermoautotrophicum; moreover, a protein cross-reacting to antiserum raised against the γ carbonic anhydrase fromMethanosarcina thermophila was detected. These results show that β-class carbonic anhydrases extend not only into theArchaea domain but also into the thermophilic prokaryotes.

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Sly, William S., et Peiyi Y. Hu. « Human Carbonic Anhydrases and Carbonic Anhydrase Deficiencies ». Annual Review of Biochemistry 64, n^o 1 (juin 1995) : 375–401. http://dx.doi.org/10.1146/annurev.bi.64.070195.002111.

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9

Silverman, David N. « The catalytic mechanism of carbonic anhydrase ». Canadian Journal of Botany 69, n^o 5 (1 mai 1991) : 1070–78. http://dx.doi.org/10.1139/b91-137.

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Water as a ligand of the zinc in carbonic anhydrase has a pKa of 7 or less and the zinc-bound hydroxide is enhanced as a nucleophile for attack on CO2. The product of catalysis is HCO3− and a proton, and the catalytic pathway as determined for vertebrate isozymes I, II, and III occurs in two separate and distinct stages. The first stage includes the hydration of CO2 and ends with the release of HCO3− from its binding site as a ligand of the zinc; its position is replaced by a water molecule. This process is described by the ratio kcat/Km; for hydration catalyzed by isozyme II, the most efficient of the carbonic anhydrases, kcat/Km is close to diffusion controlled at 108 M−1∙s−1. The second stage is the regeneration of the zinc-bound hydroxide by protolysis of water and release of a proton to the surrounding medium. For carbonic anhydrase II, this proton transfer is rate determining for the maximal turnover number kcat of 106 s−1. Its pathway includes intramolecular proton transfer from the zinc-bound water to His64 in the active-site cavity followed by proton transfer to buffer in solution. For the least efficient of the carbonic anhydrases, isozyme III, kcat/Km near 3 × 105 M−1∙s−1 is not diffusion controlled; nevertheless, proton transfer from zinc-bound water to solution is still rate limiting for a maximal turnover of 104 s−1. Carbonic anhydrase isolated from spinach chloroplasts is quite similar to vertebrate isozyme II in catalytic properties, although it has been found to have almost no sequence homology with the vertebrate carbonic anhydrases. Key words: carbonic anhydrase, CO2, catalytic mechanism, proton transfer, bicarbonate.

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Gee, Christopher W., et Krishna K. Niyogi. « The carbonic anhydrase CAH1 is an essential component of the carbon-concentrating mechanism in Nannochloropsis oceanica ». Proceedings of the National Academy of Sciences 114, n^o 17 (10 avril 2017) : 4537–42. http://dx.doi.org/10.1073/pnas.1700139114.

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Aquatic photosynthetic organisms cope with low environmental CO2 concentrations through the action of carbon-concentrating mechanisms (CCMs). Known eukaryotic CCMs consist of inorganic carbon transporters and carbonic anhydrases (and other supporting components) that culminate in elevated [CO2] inside a chloroplastic Rubisco-containing structure called a pyrenoid. We set out to determine the molecular mechanisms underlying the CCM in the emerging model photosynthetic stramenopile, Nannochloropsis oceanica, a unicellular picoplanktonic alga that lacks a pyrenoid. We characterized CARBONIC ANHYDRASE 1 (CAH1) as an essential component of the CCM in N. oceanica CCMP1779. We generated insertions in this gene by directed homologous recombination and found that the cah1 mutant has severe defects in growth and photosynthesis at ambient CO2. We identified CAH1 as an α-type carbonic anhydrase, providing a biochemical role in CCM function. CAH1 was found to localize to the lumen of the epiplastid endoplasmic reticulum, with its expression regulated by the external inorganic carbon concentration at both the transcript and protein levels. Taken together, these findings show that CAH1 is an indispensable component of what may be a simple but effective and dynamic CCM in N. oceanica.

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Liu, Qian, Xinwei Bai, Huy Pham, Jianli Hu et Cerasela Zoica Dinu. « Active Nanointerfaces Based on Enzyme Carbonic Anhydrase and Metal–Organic Framework for Carbon Dioxide Reduction ». Nanomaterials 11, n^o 4 (15 avril 2021) : 1008. http://dx.doi.org/10.3390/nano11041008.

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Carbonic anhydrases are enzymes capable of transforming carbon dioxide into bicarbonate to maintain functionality of biological systems. Synthetic isolation and implementation of carbonic anhydrases into membrane have recently raised hopes for emerging and efficient strategies that could reduce greenhouse emission and the footprint of anthropogenic activities. However, implementation of such enzymes is currently challenged by the resulting membrane’s wetting capability, overall membrane performance for gas sensing, adsorption and transformation, and by the low solubility of carbon dioxide in water, the required medium for enzyme functionality. We developed the next generation of enzyme-based interfaces capable to efficiently adsorb and reduce carbon dioxide at room temperature. For this, we integrated carbonic anhydrase with a hydrophilic, user-synthesized metal–organic framework; we showed how the framework’s porosity and controlled morphology contribute to viable enzyme binding to create functional surfaces for the adsorption and reduction of carbon dioxide. Our analysis based on electron and atomic microscopy, infrared spectroscopy, and colorimetric assays demonstrated the functionality of such interfaces, while Brunauer–Emmett–Teller analysis and gas chromatography analysis allowed additional evaluation of the efficiency of carbon dioxide adsorption and reduction. Our study is expected to impact the design and development of active interfaces based on enzymes to be used as green approaches for carbon dioxide transformation and mitigation of global anthropogenic activities.

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Dostál, Jiří, Jan Blaha, Romana Hadravová, Martin Hubálek, Olga Heidingsfeld et Iva Pichová. « Cellular Localization of Carbonic Anhydrase Nce103p in Candida albicans and Candida parapsilosis ». International Journal of Molecular Sciences 21, n^o 3 (28 janvier 2020) : 850. http://dx.doi.org/10.3390/ijms21030850.

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Pathogenic yeasts Candida albicans and Candida parapsilosis possess a ß-type carbonic anhydrase Nce103p, which is involved in CO2 hydration and signaling. C. albicans lacking Nce103p cannot survive in low CO2 concentrations, e.g., in atmospheric growth conditions. Candida carbonic anhydrases are orthologous to the Saccharomyces cerevisiae enzyme, which had originally been detected as a substrate of a non-classical export pathway. However, experimental evidence on localization of C. albicans and C. parapsilosis carbonic anhydrases has not been reported to date. Immunogold labeling and electron microscopy used in the present study showed that carbonic anhydrases are localized in the cell wall and plasmatic membrane of both Candida species. This localization was confirmed by Western blot and mass spectrometry analyses of isolated cell wall and plasma membrane fractions. Further analysis of C. albicans and C. parapsilosis subcellular fractions revealed presence of carbonic anhydrases also in the cytosolic and mitochondrial fractions of Candida cells cultivated in shaken liquid cultures, under the atmospheric conditions.

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del Pilar Corena, Maria, Theresa J. Seron, Herm K. Lehman, Judith D. Ochrietor, Andrea Kohn, Chingkuang Tu et Paul J. Linser. « Carbonic anhydrase in the midgut of larvalAedes aegypti : cloning, localization and inhibition ». Journal of Experimental Biology 205, n^o 5 (1 mars 2002) : 591–602. http://dx.doi.org/10.1242/jeb.205.5.591.

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SUMMARYThe larval mosquito midgut exhibits one of the highest pH values known in a biological system. While the pH inside the posterior midgut and gastric caeca ranges between 7.0 and 8.0, the pH inside the anterior midgut is close to 11.0. Alkalization is likely to involve bicarbonate/carbonate ions. These ions are produced in vivo by the enzymatic action of carbonic anhydrase. The purpose of this study was to investigate the role of this enzyme in the alkalization mechanism, to establish its presence and localization in the midgut of larval Aedes aegypti and to clone and characterize its cDNA. Here, we report the physiological demonstration of the involvement of carbonic anhydrase in midgut alkalization. Histochemistry and in situ hybridization showed that the enzyme appears to be localized throughout the midgut, although preferentially in the gastric caeca and posterior regions with specific cellular heterogeneity. Furthermore, we report the cloning and localization of the first carbonic anhydrase from mosquito larval midgut. A cDNA clone from Aedes aegypti larval midgut revealed sequence homology to α-carbonic anhydrases from vertebrates. Bioinformatics indicates the presence of at least six carbonic anhydrases or closely related genes in the genome of another dipteran, the fruit fly Drosophila melanogaster. Molecular analyses suggest that the larval mosquito may also possess multiple forms.

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James, Paul, Michail N. Isupov, Christopher Sayer, Vahid Saneei, Svein Berg, Maria Lioliou, Hans Kristian Kotlar et Jennifer A. Littlechild. « The structure of a tetrameric α-carbonic anhydrase fromThermovibrio ammonificansreveals a core formed around intermolecular disulfides that contribute to its thermostability ». Acta Crystallographica Section D Biological Crystallography 70, n^o 10 (27 septembre 2014) : 2607–18. http://dx.doi.org/10.1107/s1399004714016526.

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Carbonic anhydrase enzymes catalyse the reversible hydration of carbon dioxide to bicarbonate. A thermophilicThermovibrio ammonificansα-carbonic anhydrase (TaCA) has been expressed inEscherichia coliand structurally and biochemically characterized. The crystal structure of TaCA has been determined in its native form and in two complexes with bound inhibitors. The tetrameric enzyme is stabilized by a unique core in the centre of the molecule formed by two intersubunit disulfides and a single lysine residue from each monomer that is involved in intersubunit ionic interactions. The structure of this core protects the intersubunit disulfides from reduction, whereas the conserved intrasubunit disulfides are not formed in the reducing environment of theE. colihost cytosol. When oxidized to mimic the environment of the periplasmic space, TaCA has increased thermostability, retaining 90% activity after incubation at 70°C for 1 h, making it a good candidate for industrial carbon-dioxide capture. The reduction of all TaCA cysteines resulted in dissociation of the tetrameric molecule into monomers with lower activity and reduced thermostability. Unlike other characterized α-carbonic anhydrases, TaCA does not display esterase activity towardsp-nitrophenyl acetate, which appears to result from the increased rigidity of its protein scaffold.

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Jakubowski, Maciej, Ewa Szahidewicz-Krupska et Adrian Doroszko. « The Human Carbonic Anhydrase II in Platelets : An Underestimated Field of Its Activity ». BioMed Research International 2018 (28 juin 2018) : 1–10. http://dx.doi.org/10.1155/2018/4548353.

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Carbonic anhydrases constitute a group of enzymes that catalyse reversible hydration of carbon dioxide leading to the formation of bicarbonate and proton. The platelet carbonic anhydrase II (CAII) was described for the first time in the '80s of the last century. Nevertheless, its direct role in platelet physiology and pathology still remains poorly understood. The modulation of platelet CAII action as a therapeutic approach holds promise as a novel strategy to reduce the impact of cardiovascular diseases. This short review paper summarises the current knowledge regarding the role of human CAII in regulating platelet function. The potential future directions considering this enzyme as a potential drug target and important pathophysiological chain in platelet-related disorders are described.

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Deng, Qiu-Hong, Mao-Teng Li et Long-Jiang Yu. « Cloning and Expression of Brassica napus β-Carbonic Anhydrase cDNA ». Zeitschrift für Naturforschung C 64, n^o 11-12 (1 décembre 2009) : 875–81. http://dx.doi.org/10.1515/znc-2009-11-1220.

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A new full-length β-carbonic anhydrase cDNA was obtained from Brassica napus by homologous cloning. The cDNA has an open-reading frame of 996 nucleotides, encoding 331 amino acids with a calculated molecular weight of 35,692 Da and an estimated pI value of 5.459. The deduced amino acid sequence of β-carbonic anhydrase from Brassica napus shared significant identity with β-carbonic anhydrases from Brassica carinata, Arabidopsis thaliana, and Thlaspi caerulescens (97.9%, 94%, and 93.5% identity, respectively). This cDNA was expressed in Escherichia coli BL21 (DE3) using the expression vector pET-32a(+). The expression band corresponded to the calculated mass plus the N-terminal fusion protein derived from the vector

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Fernley, R. T., J. P. Coghlan et R. D. Wright. « Purification and characterization of a high-Mr carbonic anhydrase from sheep parotid gland ». Biochemical Journal 249, n^o 1 (1 janvier 1988) : 201–7. http://dx.doi.org/10.1042/bj2490201.

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Approximately half the carbonic anhydrase activity of sheep parotid-gland homogenate is derived from a high-Mr protein [Fernley, Wright & Coghlan (1979) FEBS Lett. 105, 299-302]. This enzyme has now been purified to homogeneity, and its properties were compared with those of the well-characterized sheep carbonic anhydrase II. The protein has an apparent Mr of 540,000 as measured by gel filtration under non-denaturing conditions and an apparent subunit Mr of 45,000 as measured by SDS/polyacrylamide-gel electrophoresis. After deglycosylation with the enzyme N-glycanase the protein migrates with an apparent Mr of 36,000 on SDS/polyacrylamide-gel electrophoresis. The CO2-hydrating activity was 340 units/mg compared with 488 units/mg for sheep carbonic anhydrase II measured under identical conditions. This enzyme does not, however, hydrolyse p-nitrophenyl acetate. The enzyme contains 0.8 g-atom of zinc/mol of protein subunit. The peptide maps of the two carbonic anhydrases differ significantly from one another, indicating they are not related closely structurally. Unlike the carbonic anhydrase II isoenzyme, which has a blocked N-terminus, the high-Mr enzyme has a free glycine residue at its N-terminus.

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So, Anthony K.-C., et George S. Espie. « Cyanobacterial carbonic anhydrases ». Canadian Journal of Botany 83, n^o 7 (1 juillet 2005) : 721–34. http://dx.doi.org/10.1139/b05-057.

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Carbonic anhydrases (CAs) are ubiquitous zinc metalloenzymes that catalyze the reversible dehydration of HCO3. These enzymes are encoded by at least five distinct, evolutionarily unrelated gene families, four of which have been found among the cyanobacteria examined to date. However, the distribution and expression of these cyanobacterial α-, β-, γ-, and ∈-CAs and their homologues among species have not yet been investigated in great detail. In this study, the number, distribution, and catalytic function of known and putative CAs and CA-like proteins from a variety of freshwater and marine cyanobacteria are examined.Key words: carbonic anhydrase, carboxysome, CO2-concentrating mechanism, cyanobacteria, Prochlorococcus, Synechococcus, Synechocystis.

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Aspatwar, Ashok, Leo Syrjänen et Seppo Parkkila. « Roles of Carbonic Anhydrases and Carbonic Anhydrase Related Proteins in Zebrafish ». International Journal of Molecular Sciences 23, n^o 8 (14 avril 2022) : 4342. http://dx.doi.org/10.3390/ijms23084342.

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During recent decades, zebrafish (Danio rerio) have become one of the most important model organisms in which to study different physiological and biological phenomena. The research field of carbonic anhydrases (CAs) and carbonic anhydrase related proteins (CARPs) is not an exception to this. The best-known function of CAs is the regulation of acid–base balance. However, studies performed with zebrafish, among others, have revealed important roles for these proteins in many other physiological processes, some of which had not yet been predicted in the light of previous studies and suggestions. Examples include roles in zebrafish pigmentation as well as motor coordination. Disruption of the function of these proteins may generate lethal outcomes. In this review, we summarize the current knowledge of CA-related studies performed in zebrafish from 1993–2021 that was obtained from PubMed search.

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Dixit, Sarvesh Datta, et Shalini Singh. « in silico Modeling of Curcumin Based Sulfonamides Inhibitors of the Human trans-Membrane Carbonic Anhydrase Isozyme, hCA IX by CoMSIA ». Asian Journal of Organic & ; Medicinal Chemistry 6, n^o 4 (31 décembre 2021) : 306–9. http://dx.doi.org/10.14233/ajomc.2021.ajomc-p354.

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Carbonic anhydrases, hCAs IX and XII are applied as the markers of progression of the disease in many oxygen deficient tumours and their specially manoeuvred inhibition is directly related to containing the growth of both primary tumours and tumour growth of secondary nature. Ligand-based quantitative structure-activity relationship (QSAR) studies were carried out on curcumin related, sulphonamide derivatives as inhibitors of human trans-membrane carbonic anhydrase isozyme, hCA IX by comparative molecular field similarity analysis (CoMSIA) implemented through the SYBYL package. The capacity of the model to predict coveted compound was evaluated using test set of three compounds. The best model created was found to be of choice as it showed a r2 value of 0.811 and a cross validated coefficient q2 value of 0.617 in tripos CoMSIA hydrophobic region. Results of the present study indicated that hydrophobic region factors play an important role in carbonic anhydrase hCA IX inhibition for compounds.

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Husic, H. David. « Extracellular carbonic anhydrase of Chlamydomonas reinhardtii : localization, structural properties, and catalytic properties ». Canadian Journal of Botany 69, n^o 5 (1 mai 1991) : 1079–87. http://dx.doi.org/10.1139/b91-138.

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In the unicellular green alga Chlamydomonas reinhardtii, a form of the enzyme carbonic anhydrase that is localized outside of the plasma membrane is an inducible component of a system that is involved in inorganic carbon acquisition and concentration from the growth medium. This article contains a review and analysis of the current literature regarding the extracellular carbonic anhydrase from Chlamydomonas reinhardtii and presents some new studies on its extracellular localization, physiological role in inorganic carbon acquisition, and some of the structural and catalytic properties of the enzyme. Key words: carbonic anhydrase, Chlamydomonas reinhardtii, inorganic carbon utilization.

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Botrè, Francesco, Claudio Botrè, Elisabetta Podestà, Mauro Podda et Pietro Invernizzi. « Effect of Anti-Carbonic Anhydrase Antibodies on Carbonic Anhydrases I and II ». Clinical Chemistry 49, n^o 7 (1 juillet 2003) : 1221–23. http://dx.doi.org/10.1373/49.7.1221.

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Lee, Shen-Han, et John R. Griffiths. « How and Why Are Cancers Acidic ? Carbonic Anhydrase IX and the Homeostatic Control of Tumour Extracellular pH ». Cancers 12, n^o 6 (18 juin 2020) : 1616. http://dx.doi.org/10.3390/cancers12061616.

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The acidic tumour microenvironment is now recognized as a tumour phenotype that drives cancer somatic evolution and disease progression, causing cancer cells to become more invasive and to metastasise. This property of solid tumours reflects a complex interplay between cellular carbon metabolism and acid removal that is mediated by cell membrane carbonic anhydrases and various transport proteins, interstitial fluid buffering, and abnormal tumour-associated vessels. In the past two decades, a convergence of advances in the experimental and mathematical modelling of human cancers, as well as non-invasive pH-imaging techniques, has yielded new insights into the physiological mechanisms that govern tumour extracellular pH (pHe). In this review, we examine the mechanisms by which solid tumours maintain a low pHe, with a focus on carbonic anhydrase IX (CAIX), a cancer-associated cell surface enzyme. We also review the accumulating evidence that suggest a role for CAIX as a biological pH-stat by which solid tumours stabilize their pHe. Finally, we highlight the prospects for the clinical translation of CAIX-targeted therapies in oncology.

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Hou, Juan, Xingkang Li, Michal Kaczmarek, Pengyu Chen, Kai Li, Peng Jin, Yuanmei Liang et Maurycy Daroch. « Accelerated CO2 Hydration with Thermostable Sulfurihydrogenibium azorense Carbonic Anhydrase-Chitin Binding Domain Fusion Protein Immobilised on Chitin Support ». International Journal of Molecular Sciences 20, n^o 6 (25 mars 2019) : 1494. http://dx.doi.org/10.3390/ijms20061494.

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Carbonic anhydrases (CAs) represent a group of enzymes that catalyse important reactions of carbon dioxide hydration and dehydration, a reaction crucial to many biological processes and environmental biotechnology. In this study we successfully constructed a thermostable fusion enzyme composed of the Sulfurihydrogenibium azorense carbonic anhydrase (Saz_CA), the fastest CA discovered to date, and the chitin binding domain (ChBD) of chitinase from Bacillus circulans. Introduction of ChBD to the Saz_CA had no major impact on the effect of ions or inhibitors on the enzymatic activity. The fusion protein exhibited no negative effects up to 60 °C, whilst the fusion partner appears to protect the enzyme from negative effects of magnesium. The prepared biocatalyst appears to be thermally activated at 60 °C and could be partially purified with heat treatment. Immobilisation attempts on different kinds of chitin-based support results have shown that the fusion enzyme preferentially binds to a cheap, untreated chitin with a large crystallinity index over more processed forms of chitin. It suggests significant potential economic benefits for large-scale deployment of immobilised CA technologies such as CO2 utilisation or mineralisation.

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Soto, Amelia R., Hong Zheng, Dorinda Shoemaker, Jason Rodriguez, Betsy A. Read et Thomas M. Wahlund. « Identification and Preliminary Characterization of Two cDNAs Encoding Unique Carbonic Anhydrases from the Marine Alga Emiliania huxleyi ». Applied and Environmental Microbiology 72, n^o 8 (août 2006) : 5500–5511. http://dx.doi.org/10.1128/aem.00237-06.

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ABSTRACT Marine coccolithophorid algae are thought to play a significant role in carbon cycling due to their ability to incorporate dissolved inorganic carbon (DIC) into both calcite and photosynthetic products. Among coccolithophorids, Emiliania huxleyi is the most prolific, forming massive blooms that affect the global environment. In addition to its ecological importance, the elaborate calcite structures (coccoliths) are being investigated for the design of potential materials for science and biotechnological devices. To date, most of the research focus in this organism has involved the partitioning of DIC between calcification and photosynthesis, primarily using measurements of an external versus internal carbonic anhydrase (CA) activity under defined conditions. The actual genes, proteins, and pathways employed in these processes have not been identified and characterized (see the work of Quinn et al. in this issue [P. Quinn, R. M. Bowers, X. Zhang, T. M. Wahlund, M. A. Fanelli, D. Olszova, and B. A. Read, Appl. Environ. Microbiol. 72:5512-5526, 2006]). In this study, the cloning and preliminary characterization of two genetically distinct carbonic anhydrase cDNAs are described. Phylogenetic analysis indicated that these two genes belonged to the gamma (γ-EhCA2) and delta (δ-EhCA1) classes of carbonic anhydrases. The deduced amino acid sequence of δ-EhCA1 revealed that it encodes a protein of 702 amino acids (aa) (ca. 77.3 kDa), with a transmembrane N-terminal region of 373 aa and an in-frame C-terminal open reading frame of 329 aa that defines the CA region. The γ-EhCA2 protein was 235 aa in length (ca. 24.9 kDa) and was successfully expressed in Escherichia coli BL21(DE3) and purified as an active recombinant CA. The expression levels of each transcript from quantitative reverse transcription-PCR experiments under bicarbonate limitation and over a 24-h time course suggest that these isozymes perform different functions in E. huxleyi.

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Bedu, S., et F. Joset. « Studies on the carbonic anhydrase activity in Synechocystis PCC6803 wild type and an acetazolamide-resistant mutant ». Canadian Journal of Botany 69, n^o 5 (1 mai 1991) : 1103–8. http://dx.doi.org/10.1139/b91-141.

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The problem of the role and the localization of carbonic anhydrase activity in cyanobacteria has been addressed by two approaches using strain Synechocystis PCC6803. Physiological analysis of the differential effects of carbonic anhydrase inhibitors on the entry and accumulation of CO2 in cells grown under low or high inorganic carbon concentrations and determination of carbonic anhydrase activities in cellular subfractions led to the hypothesis of the presence of two different enzymes in this strain. This conclusion is compatible with current models. Only the internal enzyme could be regulated by variations of the external inorganic carbon concentrations. A parallel analysis of a mutant of this strain resistant to the inhibitor acetazolamide supported the hypothesis of the presence of two enzymes. This clone would be selectively impaired in the carbonic anhydrase activity involved in the maintenance of the internal CO2 pool, while its transport capacity is unchanged. Key words: carbonic anhydrase, physiological role, localization, inhibitors, cyanobacteria, mutant.

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Carta, Fabrizio, Pascal Dumy, Claudiu T. Supuran et Jean-Yves Winum. « Multivalent Carbonic Anhydrases Inhibitors ». International Journal of Molecular Sciences 20, n^o 21 (28 octobre 2019) : 5352. http://dx.doi.org/10.3390/ijms20215352.

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Biomolecular recognition using a multivalent strategy has been successfully applied, this last decade on several biological targets, especially carbohydrate-processing enzymes, proteases, and phosphorylases. This strategy is based on the fact that multivalent interactions of several inhibitory binding units grafted on a presentation platform may enhance the binding affinity and selectivity. The zinc metalloenzymes carbonic anhydrases (CAs, EC 4.2.1.1) are considered as drug targets for several pathologies, and different inhibitors found clinical applications as diuretics, antiglaucoma agents, anticonvulsants, and anticancer agents/diagnostic tools. Their main drawback is related to the lack of isoform selectivity leading to serious side effects for all pathologies in which they are employed. Thus, the multivalent approach may open new opportunities in the drug design of innovative isoform-selective carbonic anhydrase inhibitors with biomedical applications.

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Mogensen, Estelle Gewiss, Guilhem Janbon, James Chaloupka, Clemens Steegborn, Man Shun Fu, Frédérique Moyrand, Torsten Klengel et al. « Cryptococcus neoformans Senses CO2 through the Carbonic Anhydrase Can2 and the Adenylyl Cyclase Cac1 ». Eukaryotic Cell 5, n^o 1 (janvier 2006) : 103–11. http://dx.doi.org/10.1128/ec.5.1.103-111.2006.

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ABSTRACT Cryptococcus neoformans, a fungal pathogen of humans, causes fatal meningitis in immunocompromised patients. Its virulence is mainly determined by the elaboration of a polysaccharide capsule surrounding its cell wall. During its life, C. neoformans is confronted with and responds to dramatic variations in CO2 concentrations; one important morphological change triggered by the shift from its natural habitat (0.033% CO2) to infected hosts (5% CO2) is the induction of capsule biosynthesis. In cells, CO2 is hydrated to bicarbonate in a spontaneous reaction that is accelerated by carbonic anhydrases. Here we show that C. neoformans contains two β-class carbonic anhydrases, Can1 and Can2. We further demonstrate that CAN2, but not CAN1, is abundantly expressed and essential for the growth of C. neoformans in its natural environment, where CO2 concentrations are limiting. Structural studies reveal that Can2 forms a homodimer in solution. Our data reveal Can2 to be the main carbonic anhydrase and suggest a physiological role for bicarbonate during C. neoformans growth. Bicarbonate directly activates the C. neoformans Cac1 adenylyl cyclase required for capsule synthesis. We show that this specific activation is optimal at physiological pH.

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Kim, Geumsoo, Tae-Hoon Lee, Petra Wetzel, Cornelia Geers, Mary Ann Robinson, Timothy G. Myers, Jennie W. Owens et al. « Carbonic Anhydrase III Is Not Required in the Mouse for Normal Growth, Development, and Life Span ». Molecular and Cellular Biology 24, n^o 22 (15 novembre 2004) : 9942–47. http://dx.doi.org/10.1128/mcb.24.22.9942-9947.2004.

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ABSTRACT Carbonic anhydrase III is a cytosolic protein which is particularly abundant in skeletal muscle, adipocytes, and liver. The specific activity of this isozyme is quite low, suggesting that its physiological function is not that of hydrating carbon dioxide. To understand the cellular roles of carbonic anhydrase III, we inactivated the Car3 gene. Mice lacking carbonic anhydrase III were viable and fertile and had normal life spans. Carbonic anhydrase III has also been implicated in the response to oxidative stress. We found that mice lacking the protein had the same response to a hyperoxic challenge as did their wild-type siblings. No anatomic alterations were noted in the mice lacking carbonic anhydrase III. They had normal amounts and distribution of fat, despite the fact that carbonic anhydrase III constitutes about 30% of the soluble protein in adipocytes. We conclude that carbonic anhydrase III is dispensable for mice living under standard laboratory husbandry conditions.

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Merrett, M. J. « Inorganic carbon transport in some marine microalgal species ». Canadian Journal of Botany 69, n^o 5 (1 mai 1991) : 1032–39. http://dx.doi.org/10.1139/b91-133.

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Inorganic carbon transport was investigated in a range of marine microalgae. A small-celled strain of Stichococcus bacillaris, containing appreciable carbonic anhydrase activity, showed a high affinity for CO2, while measurement of the internal inorganic carbon pool by the silicone oil layer centrifugal filtering technique showed cells concentrated inorganic carbon up to 20-fold in relation to the external medium at pH 5.0 but not pH 8.3. The addition of 14CO2 or H14CO3− to cells in short-term kinetic experiments at pH 8.3 confirmed that only CO2 provides the exogenous substrate for substantial inorganic carbon accumulation within the cell. High-affinity HCO3− transport in Phaeodactylum tricornutum and Porphyridium purpureum is dependent on sodium ions, while intracellular carbonic anhydrase increased the steady-state flux of CO2 from inside the plasmalemma to Rubisco. In the presence of HCO3− the intracellular pH in cells of P. purpureum is 7.1 but on carbon starvation the pH falls to 6.0. Ethoxyzolamide blocks bicarbonate-dependent alkalinization of the cytosol, confirming a central role for carbonic anhydrase–bicarbonate in cytosolic pH regulation. Carbonic anhydrase activity is pH dependent in P. purpureum so synergistic interaction between CO2 uptake and bicarbonate transport may occur.

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Pierre, Alain C. « Enzymatic Carbon Dioxide Capture ». ISRN Chemical Engineering 2012 (16 décembre 2012) : 1–22. http://dx.doi.org/10.5402/2012/753687.

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In the past decade, the capture of anthropic carbonic dioxide and its storage or transformation have emerged as major tasks to achieve, in order to control the increasing atmospheric temperature of our planet. One possibility rests on the use of carbonic anhydrase enzymes, which have been long known to accelerate the hydration of neutral aqueous CO2 molecules to ionic bicarbonate species. In this paper, the principle underlying the use of these enzymes is summarized. Their main characteristics, including their structure and catalysis kinetics, are presented. A special section is next devoted to the main types of CO2 capture reactors under development, to possibly use these enzymes industrially. Finally, the possible application of carbonic anhydrases to directly store the captured CO2 as inert solid carbonates deserves a review presented in a final section.

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Bhakta, Abhijit, Maitreyi Bandyopadhyay, Sayantan Dasgupta, Santanu Sen, Arun Kumar et Utpal Kumar Biswas. « Effect of NaHS on carbonic anhydrase activity of human erythrocyte ». Asian Journal of Medical Sciences 7, n^o 3 (6 janvier 2016) : 23–27. http://dx.doi.org/10.3126/ajms.v7i3.14047.

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Background: In contrast to its role as poison, hydrogen sulfide (H2S) is recently considered as a gaso-transmitter which mediates important physiologic functions in humans. Evidence is accumulating to demonstrate that inhibitors of H2S production or therapeutic H2S donor compounds exert significant effects in various experimental models. Carbonic anhydrases (CA) are a group of zinc-containing metalloenzymes that catalyse the reversible hydration of carbon dioxide. CAs activity in erythrocytes (CAI and CAII) has recently been observed to be associated with various pathological conditions especially in diabetes mellitus, hypertension and lipid disorders. Alteration of this enzyme activity has been reported by the effect of advanced glycation end products methylglyoxal and reduced glutathione. Aims and Objectives: As H2S, being a mediator of many physiological functions and synthesized in vivo, may affect functions of many intracellular proteins like carbonic anhydrase, the objective of this study is to find out if there is any change in the carbonic anhydrase activity under the effect of H2S- donor NaHS in dose dependant manner using RBC model in vitro.Materials and Methods: Blood sample was collected from forty (40) numbers of healthy volunteers of 18-40 years of in heparin containing vials and packed cells were prepared immediately by centrifugation The packed erythrocytes were washed three times with normal saline and diluted (1:10) with the normal saline. One ml each of diluted packed cells was taken in eight test tubes. Serial dilutions of NaHS (1to 250 µMol/L) was added to all the test tubes except for the first test tube where only normal saline was added and incubated at room temperature for one hour. Haemolysates was prepared from the erythrocytes with equal volume of distilled water in each tube and the CA activity was determined in the haemolysates using standardized method.Results: There is significant increase of CA activity in dose dependent manner under the effect of NaHS and also compared to the activity of hemolysate prepared without NaHS. Conclusions:Our study for the first time demonstrated that the Carbonic Anhydrase activity of erythrocytes is significantly increases by the effect of NaHS and this study reveals some important biological role of H2S and carbonic anhydrase.Asian Journal of Medical Sciences Vol. 7(3) 2016 23-27

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Ali, Majid, Murat Bozdag, Umar Farooq, Andrea Angeli, Fabrizio Carta, Paola Berto, Giuseppe Zanotti et Claudiu T. Supuran. « Benzylaminoethyureido-Tailed Benzenesulfonamides : Design, Synthesis, Kinetic and X-ray Investigations on Human Carbonic Anhydrases ». International Journal of Molecular Sciences 21, n^o 7 (7 avril 2020) : 2560. http://dx.doi.org/10.3390/ijms21072560.

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A drug design strategy of carbonic anhydrase inhibitors (CAIs) belonging to sulfonamides incorporating ureidoethylaminobenzyl tails is presented. A variety of substitution patterns on the ring and the tails, located on para- or meta- positions with respect to the sulfonamide warheads were incorporated in the new compounds. Inhibition of human carbonic anhydrases (hCA) isoforms I, II, IX and XII, involving various pathologies, was assessed with the new compounds. Selective inhibitory profile towards hCA II was observed, the most active compounds being low nM inhibitors (KIs of 2.8–9.2 nM, respectively). Extensive X-ray crystallographic analysis of several sulfonamides in an adduct with hCA I allowed an in-depth understanding of their binding mode and to lay a detailed structure-activity relationship.

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de Goeyse, Siham, Alice E. Webb, Gert-Jan Reichart et Lennart J. de Nooijer. « Carbonic anhydrase is involved in calcification by the benthic foraminifer <i>Amphistegina lessonii</i> ; ». Biogeosciences 18, n^o 2 (18 janvier 2021) : 393–401. http://dx.doi.org/10.5194/bg-18-393-2021.

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Abstract. Marine calcification is an important component of the global carbon cycle. The mechanism by which some organisms take up inorganic carbon for the production of their shells or skeletons, however, remains only partly known. Although foraminifera are responsible for a large part of the global calcium carbonate production, the process by which they concentrate inorganic carbon is debated. Some evidence suggests that seawater is taken up by vacuolization and participates relatively unaltered in the process of calcification, whereas other results suggest the involvement of transmembrane transport and the activity of enzymes like carbonic anhydrase. Here, we tested whether inorganic-carbon uptake relies on the activity of carbonic anhydrase using incubation experiments with the perforate, large benthic, symbiont-bearing foraminifer Amphistegina lessonii. Calcification rates, determined by the alkalinity anomaly method, showed that inhibition of carbonic anhydrase by acetazolamide (AZ) stopped most of the calcification process. Inhibition of photosynthesis either by 3-(3,4-Dichlorophenyl)-1,1-dimethylurea (DCMU) or by incubating the foraminifera in the dark also decreased calcification rates but to a lesser degree than with AZ. Results from this study show that carbonic anhydrase plays a key role in biomineralization of Amphistegina lessonii and indicates that calcification of those perforate, large benthic foraminifera might, to a certain extent, benefit from the extra dissolved inorganic carbon (DIC), which causes ocean acidification.

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Arancibia-Avila, Patricia, John R. Coleman, William A. Russin, Lee W. Wilcox, James M. Graham et Linda E. Graham. « Effects of pH on cell morphology and carbonic anhydrase activity and localization in bloom-forming Mougeotia (Chlorophyta, Charophyceae) ». Canadian Journal of Botany 78, n^o 9 (1 septembre 2000) : 1206–14. http://dx.doi.org/10.1139/b00-100.

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A species of Mougeotia (C.A. Agardh) that was the dominant component of a metaphytic bloom-forming filamentous algal assemblage in an experimentally acidified lake (Little Rock Lake, Vilas County, Wisconsin, U.S.A.) was isolated into unialgal culture for analysis of pH effects on cell morphology and carbonic anhydrase activity and localization. External and total carbonic anhydrase activities at pH 8 were significantly greater than those at pH 5, but internal carbonic anhydrase activities were not significantly different at the two pH levels, as determined by use of a potentiometric technique. Ultrastructural immunogold labeling with a polyclonal antibody to Chlamydomonas periplasmic carbonic anhydrase suggested that an antigenically similar protein was located in the periplasmic space, inflated end walls, chloroplast, and peripheral cytoplasm of Mougeotia grown at both pH 8 and 5. Activity measurements and localization data were consistent with the hypothesis that a carbon concentration mechanism operates in this Mougeotia species at both high and low pH. Growth form, cell dimensions, chloroplast morphology, and cell wall ultrastructure were significantly different in cultures grown at pH 5 and pH 8. These structural and carbon acquisition features may contribute to Mougeotia's ability to form conspicuous metaphytic blooms in acidified waters.Key words: carbonic anhydrase, acidification, algal blooms, Mougeotia.

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KarataÅŸ, Mert Olgun, Serkan Dayan, NilgÃ¼n KayacÄ±, Ã‡iÄŸdem Bilen, Emre Yavuz, Nahit Gencer, BÃ¼lent AlÄ±cÄ±, NilgÃ¼n Ozpozan KalaycÄ±oÄŸlu et Oktay Arslan. « Coumarin or benzoxazinone bearing benzimidazolium and bis(benzimidazolium) salts ; involvement in transfer hydrogenation of acetophenone derivatives and hCA inhibition ». Mediterranean Journal of Chemistry 4, n^o 5 (19 octobre 2015) : 252–60. http://dx.doi.org/10.13171/mjc.4.5.2015.17.10.08.51/karatas.

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Four new salts of benzimidazolium and bis(benzimidazolium) which include coumarin or benzoxazinone moieties were synthesized and the structures of the newly synthesized compounds were elucidated on the basis of spectral analyses such as 1H-NMR, 13C-NMR, HSQC, IR, LC-MS and elemental analysis. Benzimidazolium salts were used intensively as N-heterocyclic carbene (NHC) precursors in the various catalytic reactions such as transfer hydrogenation (TH), C-H bond activation, Heck, Suzuki reaction etc. With the prospect of potential NHC precursor properties of the synthesized compounds, they were employed in the (TH) reaction of p-substitute acetophenones (acetophenone, p-methyl acetophenone, p-chloro acetophenone) and good yields were observed. Coumarin compounds are known as inhibitor of carbonic anhydrase and inhibition effects of the synthesized compounds on human carbonic anhydrases (hCA) were investigated as in vitro. The in vitro results demonstrated that all compounds inhibited hCA I and hCA II activity. Among the synthesized compounds 1,4-bis(1-((6,8-dimethyl-2H-chromen-2-one-4-yl)methyl)benzimidazolium-3-yl)butane dichloride was found to be the most active IC50= 5.55 mM and 6.06 mM for hCA I and hCA II, respectively.

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Rivera, Amariliz, Vanessa Espinosa, Orchi Dutta, Everett K. Henry et Mark C. Siracusa. « Neutrophils license antifungal monocyte responses via carbonic anhydrase 4 modulation ». Journal of Immunology 196, n^o 1_Supplement (1 mai 2016) : 134.7. http://dx.doi.org/10.4049/jimmunol.196.supp.134.7.

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Abstract Neutropenia is a significant risk factor for life threatening invasive fungal infections (IFI). Neutrophils are well known as important innate cells that promote the direct eradication of fungal pathogens but whether they mediate antifungal defense beyond their role as effectors is unclear. Here we demonstrate that a pulmonary infection with the clinically relevant fungal pathogen Aspergillus fumigatus induces the diversification of specialized antifungal neutrophils that are required for antifungal CCR2+ monocyte-derived dendritic cell (mo-DC) function. Selective depletion of neutrophils resulted in global transcriptional alterations of the antifungal CCR2+ monocyte response, limited mo-DC differentiation, and diminished conidiacidal activity. Impaired mo-DC antifungal activity in neutropenic mice was accompanied by significant upregulation of carbonic anhydrase 4 (Car4) expression in CCR2+ monocyte precursors. Pharmacological inhibition of Car4 with the FDA-approved drug methazolamide (MZ) rescued the antifungal response of mo-DC and protected neutropenic mice from invasive apergillosis. Thus, beyond their role as effectors, antifungal neutrophils facilitate antifungal mo-DC functions by regulating Car4 activity. Moreover, our data provide proof-of-principle evidence for the importance of carbonic anhydrases in shaping innate cell differentiation as well as for the off-label therapeutic benefit of carbonic anhydrase inhibitors to boost antifungal immunity in susceptible patient populations.

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Dodgson, S. J., et K. Cherian. « Mitochondrial carbonic anhydrase is involved in rat renal glucose synthesis ». American Journal of Physiology-Endocrinology and Metabolism 257, n^o 6 (1 décembre 1989) : E791—E796. http://dx.doi.org/10.1152/ajpendo.1989.257.6.e791.

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At 37 degrees C, pH 7.4, carbonic anhydrase activity (kenz) of disrupted rat renal proximal tubules and cortical mitochondria was 2.5 +/- 0.8 (n = 3) and 0.15 +/- 0.40 (n = 3) ml.mg-1.s-1, respectively. Turnover number for renal mitochondrial carbonic anhydrase (CA V) was 24,000 s-1. CA V activity of intact mitochondria was completely inhibited by 0.15 microM ethoxzolamide (EZ). Intact proximal tubules, prepared from 48-h starved male rats, were incubated at 37 degrees C in 10 mM pyruvate in Krebs-Henseleit bicarbonate saline buffer, 5% CO2-95% O2. The rate of glucose synthesis over 60 min was reduced 50% by including 0.6 microM EZ in the incubation solution. The concentration of NaHCO3 was doubled to 50 mM (with a corresponding decrease in NaCl) and the solution gassed with 10% CO2-90% O2; 2.4 microM EZ no longer decreased glucose synthesis. It was concluded that inhibition of glucose synthesis by EZ was directly a result of inhibiting the carbonic anhydrases. The rate of glucose production was subsequently determined with tubules incubating in a HCO3(-)-free N-2-hydroxyethylpiperazine-N'-2-ethane-sulfonic acid (HEPES) buffer; this rate was decreased 50% by 0.6 microM EZ. These data support the hypotheses that CA V provides HCO3- for pyruvate carboxylase and that CO2 can be provided by tubular metabolism. Intact tubules were incubated in from 5 to 20 mM pyruvate in either 25 or 50 mM HCO3-; in either buffer, the rate of glucose synthesis was similar, increasing with increasing pyruvate concentration. At no pyruvate concentration was there a change in the rate of glucose production when tubules were incubated in 50 mM HCO3- buffer with 1.6 microM EZ. These data also support the hypothesis that CA V provides the HCO3- substrate for pyruvate carboxylation when there is a high rate of intracellular CO2 production and external CO2 is low. It is further concluded that the cytosolic carbonic anhydrase (CA II) and the membrane-bound carbonic anhydrase (CA IV) are not involved in glucose synthesis from pyruvate.

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Pander, Bart, Gemma Harris, David J. Scott, Klaus Winzer, Michael Köpke, Sean D. Simpson, Nigel P. Minton et Anne M. Henstra. « The carbonic anhydrase of Clostridium autoethanogenum represents a new subclass of β-carbonic anhydrases ». Applied Microbiology and Biotechnology 103, n^o 17 (25 juillet 2019) : 7275–86. http://dx.doi.org/10.1007/s00253-019-10015-w.

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Korhonen, Katariina, Anna-Kaisa Parkkila, Pauli Helen, Ritva Välimäki, Silvia Pastorekova, Jaromir Pastorek, Seppo Parkkila et Hannu Haapasalo. « Carbonic anhydrases in meningiomas : association of endothelial carbonic anhydrase II with aggressive tumor features ». Journal of Neurosurgery 111, n^o 3 (septembre 2009) : 472–77. http://dx.doi.org/10.3171/2008.10.17672.

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Object Carbonic anhydrase (CA) II and IX are enzymes involved in pH homeostasis and have been shown to be upregulated in several types of cancer. In this study, the authors evaluate the expression of CA II and IX in meningiomas and assess their relationship to patient age, tumor type and grade, tumor sex hormone receptor status, tumor cell proliferation, and tumor recurrence. Methods This study was conducted in consecutive patients who underwent meningioma surgeries at Tampere University Hospital between 1989 and 1999. The expression of CA II and IX was studied immunohistochemically using a tissue microarray technique and specific antibodies. Results Immunohistological staining with CA II and IX was assessed in 443 primary and 67 recurrent tumor specimens. Of these samples, 455 were benign (WHO Grade I), 49 atypical (Grade II), and 6 malignant (Grade III). Endothelial cells in 14.8% of the tumors stained positively for CA II. Tumor cells were positive for CA IX in 11.6% of the cases. Endothelial CA II expression correlated with increasing histological grade (p = 0.002), and tumor proliferation rates were higher in CA II+ versus CA II− cases (p = 0.002). Androgen receptor–negative tumors were found to be CA II+ significantly more often than androgen receptor–positive tumors (p = 0.001). No associations were found with the CA IX enzyme. Conclusions Carbonic anhydrase II positivity in the endothelium was associated with cell proliferation and malignancy grade. These results suggest that CA II expression is associated with malignant progression of meningiomas and could thus be a target molecule for anticancer therapy.

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Abbas, Saghir, Sumera Zaib, Shafiq Ur Rahman, Saqib Ali, Shahid Hameed, Muhammad N. Tahir, Khurram S. Munawar, Farzana Shaheen, Syed M. Abbas et Jamshed Iqbal. « Carbonic Anhydrase Inhibitory Potential of 1,2,4-triazole-3-thione Derivatives of Flurbiprofen, Ibuprofen and 4-tert-butylbenzoic Hydrazide : Design, Synthesis, Characterization, Biochemical Evaluation, Molecular Docking and Dynamic Simulation Studies ». Medicinal Chemistry 15, n^o 3 (12 avril 2019) : 298–310. http://dx.doi.org/10.2174/1573406414666181012165156.

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Background:The over-expression of the carbonic anhydrases results in some specific carcinomas including pancreatic, gastric and brain tumor. Tumors are distinguished under hypoxic conditions and various investigations are being carried out to target the known hypoxic areas of the tumors to increase the sensitivity towards standard therapeutic treatment.Objective:Herein, we have designed and synthesized some biologically important esters, hydrazides, thiocarbamates, 1,2,4-triazole-3-thiones and Schiff bases. The purpose of the research was to evaluate the derivative against carbonic anhydrase and to assess the toxicity of the same compounds.Method:The structures of all the compounds were characterized by FT-IR, mass spectrometry, elemental analysis, 1H and 13C NMR spectroscopy. The synthetic derivatives were screened for their inhibitory potential against carbonic anhydrase II by in vitro assay. Double reciprocal plots for inhibition kinetics of the potent compounds were constructed and mode of inhibition was determined. Furthermore, to check the cytotoxicity, these derivatives were tested against human breast adenocarcinoma by MTT method.Results:X-ray diffraction analysis of the compounds 10, 14 and 15 showed that they did not have any π-π or C-H…&π interactions. The experimental results were validated by molecular docking and dynamic simulations of the potent compounds in the active pocket of enzyme. Important binding interactions of potent compounds with the key residues in the active site of the carbonic anhydrase enzyme were revealed. Drug likeness profile of the derivatives was evaluated to determine the physicochemical properties.Conclusion:The proposed synthetic approach provides a suitable platform for the generation of a new library of compounds which could potentially be employed in the future testing and optimization of inhibitor potencies.

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Johnston, Andrew M. « The acquisition of inorganic carbon by marine macroalgae ». Canadian Journal of Botany 69, n^o 5 (1 mai 1991) : 1123–32. http://dx.doi.org/10.1139/b91-144.

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Marine macroalgae inhabit three different environments: the eulittoral zone, rock pools, and the sublittoral zone. Many macroalgae exhibit C4 gas exchange characteristics, i.e., low CO2 compensation point, high pH compensation point, photosynthesis insensitive to changes in oxygen changes below 21 kPa, and a high affinity for inorganic carbon. It is concluded that in general eulittoral and rock-pool species are more C4-like than the subtidal species though there are interesting exceptions. Experimental evidence points to the following mechanisms being involved in inorganic carbon acquisition by macroalgae. The role of β-carboxylation as the primary step in carbon fixation is only convincing in Udotea flabellum, while PGA is the first product of 14C fixation in most species. Direct evidence of inorganic carbon accumulation is only available for Ulva fasciata, whereas Chondrus crispus does not have this ability. Studies show that carbonic anhydrase is prominent in the mechanism of carbon acquisition by Ascophyllum nodosum, and when inhibited the alga is dependent on CO2, whereas U. fasciata retains some ability to use bicarbonate ions. It is concluded that macroalgae display a range of inorganic carbon assimilation mechanisms that are active to varying degrees. The relationships between these mechanisms, the different macroalgal habitats, and carbonic anhydrase is discussed. Key words: inorganic carbon concentrating mechanisms, macroalgae, carbonic anhydrase.

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Tsuzuki, Mikio, et Shigetoh Miyachi. « CO2 syndrome in Chlorella ». Canadian Journal of Botany 69, n^o 5 (1 mai 1991) : 1003–7. http://dx.doi.org/10.1139/b91-129.

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Effects of CO2 concentration on microalgae, especially on Chlorella, are discussed from the aspect of the high affinity of microalgae for inorganic carbon (Ci) in photosynthesis. Accumulation of Ci and carbonic anhydrase are the two main factors underlying the high affinity for Ci. The other factors such as development of carboxysomes and pyrenoids under low CO2 conditions may also be important. Contribution of each factor to the high affinity for Ci in photosynthesis seems to differ from species to species. Key words: Chlorella, inorganic carbon transport, carbonic anhydrase, fatty acids composition, CO2.

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Kim, Soo Cheol, Kap Seong Choi, Jung Woo Kim, Myeong Rak Choi, Kyeong Ho Han, Won Kyo Lee et Kang Hee Kho. « Detection of Carbonic Anhydrase in the Gills of Rainbow Trout (Oncorhynchus mykiss) ». Journal of Life Science 23, n^o 12 (30 décembre 2013) : 1557–61. http://dx.doi.org/10.5352/jls.2013.23.12.1557.

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Wood, J. M., D. J. Hussey, C. M. Woods, D. I. Watson et A. S. Carney. « Biomarkers and laryngopharyngeal reflux ». Journal of Laryngology & ; Otology 125, n^o 12 (14 septembre 2011) : 1218–24. http://dx.doi.org/10.1017/s0022215111002234.

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AbstractLaryngopharyngeal reflux is a controversial but increasingly made diagnosis used in patients with a collection of often non-specific laryngeal symptoms. It is a clinical diagnosis, and its pathophysiology is currently poorly understood.Previous reflux research has focused on injurious agents, acid, pepsin and biomarker expression. Failure of intrinsic defences in the larynx may cause changes in laryngeal epithelia, particularly alterations in carbonic anhydrases and E-cadherin. Carbonic anhydrase III levels vary in the larynx in response to laryngopharyngeal reflux, depending on location. Expression of E-cadherin, a known tumour suppressor, is reduced in the presence of reflux. Mucin expression also varies according to the severity of reflux.Further research is required to define the clinical entity of laryngopharyngeal reflux, and to identify a definitive mechanism for mucosal injury. Understanding this mechanism should allow the development of a comprehensive model, which would enable future diagnostic and therapeutic interventions to be developed.

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Perry, S. F., K. M. Gilmour, N. J. Bernier et C. M. Wood. « Does gill boundary layer carbonic anhydrase contribute to carbon dioxide excretion : a comparison between dogfish (Squalus acanthias) and rainbow trout (Oncorhynchus mykiss) ». Journal of Experimental Biology 202, n^o 6 (15 mars 1999) : 749–56. http://dx.doi.org/10.1242/jeb.202.6.749.

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In vivo experiments were conducted on spiny dogfish (Squalus acanthias) and rainbow trout (Oncorhynchus mykiss) in sea water to determine the potential role of externally oriented or gill boundary layer carbonic anhydrase in carbon dioxide excretion. This was accomplished by assessing pH changes in expired water using a stopped-flow apparatus. In dogfish, expired water was in acid-base disequilibrium as indicated by a pronounced acidification (delta pH=−0.11+/−0.01; N=22; mean +/− s.e.m.) during the period of stopped flow; inspired water, however, was in acid-base equilibrium (delta pH=−0.002+/−0.01; N=22). The acid-base disequilibrium in expired water was abolished (delta pH=−0.005+/−0.01; N=6) by the addition of bovine carbonic anhydrase (5 mg l-1) to the external medium. Addition of the carbonic anhydrase inhibitor acetazolamide (1 mmol l-1) to the water significantly reduced the magnitude of the pH disequilibrium (from −0.133+/−0.03 to −0.063+/−0.02; N=4). However, after correcting for the increased buffering capacity of the water caused by acetazolamide, the acid-base disequilibrium during stopped flow was unaffected by this treatment (control delta [H+]=99.8+/−22.8 micromol l-1; acetazolamide delta [H+]=81.3+/−21.5 micromol l-1). In rainbow trout, expired water displayed an acid-base disequilibrium (delta pH=0.09+/−0.01; N=6) that also was abolished by the application of external carbonic anhydrase (delta pH=0.02+/−0.01).The origin of the expired water acid-base disequilibrium was investigated further in dogfish. Intravascular injection of acetazolamide (40 mg kg-1) to inhibit internal carbonic anhydrase activity non-specifically and thus CO2 excretion significantly diminished the extent of the expired water disequilibrium pH after 30 min (from −0.123+/−0.01 to −0.065+/−0.01; N=6). Selective inhibition of extracellular carbonic anhydrase activity using a low intravascular dose (1.3 mg kg-1) of the inhibitor benzolamide caused a significant reduction in the acid-base disequilibrium after 5 min (from −0.11+/−0.01 to −0.07+/−0. 01; N=14). These results demonstrate that the expired water acid-base disequilibrium originates, at least in part, from excretory CO2 and that extracellular carbonic anhydrase in dogfish may have a significant role in carbon dioxide excretion. However, externally oriented carbonic anhydrase (if present in dogfish) plays no role in catalysing the hydration of the excretory CO2 in water flowing over the gills and thus is unlikely to facilitate CO2 excretion.

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Morel, François M. M., Phoebe J. Lam et Mak A. Saito. « Trace Metal Substitution in Marine Phytoplankton ». Annual Review of Earth and Planetary Sciences 48, n^o 1 (30 mai 2020) : 491–517. http://dx.doi.org/10.1146/annurev-earth-053018-060108.

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The sinking of organic matter to the deep ocean leaves extremely low concentrations of major and trace nutrients for photosynthetic organisms at the sunlit surface. As a result, marine phytoplankton make use of alternative sources of essential elements and have evolved to substitute some elements by others in various biochemical processes. A particularly intriguing example is that of Zn, which is used in many biochemical functions but is often depleted down to picomolar concentrations in surface seawater. Laboratory data show that many phytoplankton species are able to achieve high growth rates by replacing Zn with Cd or Co in cultures. One documented biochemical replacement occurs in some carbonic anhydrases that are used in the acquisition of inorganic carbon for photosynthesis. Field data show the existence of such enzymes in surface seawater and indicate a replacement of Zn by Cd and Co in the surface waters of the eastern tropical South Pacific. Those results point at interesting opportunities for future research. ▪ The dearth of essential elements in surface seawater has caused marine phytoplankton to substitute some trace metals by others in various biochemical processes. ▪ Many species can substitute Cd and/or Co for Zn as a metal center in carbonic anhydrase enzymes that are used in the acquisition of inorganic carbon for photosynthesis. ▪ Field data show the presence of such enzymes in the sea and indicate a replacement of Zn by Cd and Co in the surface upwelling waters of the eastern tropical South Pacific. ▪ New analytical and molecular tools provide opportunities to elucidate the unusual biochemistry of marine phytoplankton.

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Runtsch, Leander Simon, David Michael Barber, Peter Mayer, Michael Groll, Dirk Trauner et Johannes Broichhagen. « Azobenzene-based inhibitors of human carbonic anhydrase II ». Beilstein Journal of Organic Chemistry 11 (7 juillet 2015) : 1129–35. http://dx.doi.org/10.3762/bjoc.11.127.

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Aryl sulfonamides are a widely used drug class for the inhibition of carbonic anhydrases. In the context of our program of photochromic pharmacophores we were interested in the exploration of azobenzene-containing sulfonamides to block the catalytic activity of human carbonic anhydrase II (hCAII). Herein, we report the synthesis and in vitro evaluation of a small library of nine photochromic sulfonamides towards hCAII. All molecules are azobenzene-4-sulfonamides, which are substituted by different functional groups in the 4´-position and were characterized by X-ray crystallography. We aimed to investigate the influence of electron-donating or electron-withdrawing substituents on the inhibitory constant K i. With the aid of an hCAII crystal structure bound to one of the synthesized azobenzenes, we found that the electronic structure does not strongly affect inhibition. Taken together, all compounds are strong blockers of hCAII with K i = 25–65 nM that are potentially photochromic and thus combine studies from chemical synthesis, crystallography and enzyme kinetics.

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Giri, Anand, et Deepak Pant. « Carbonic anhydrase modification for carbon management ». Environmental Science and Pollution Research 27, n^o 2 (3 décembre 2019) : 1294–318. http://dx.doi.org/10.1007/s11356-019-06667-w.

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Lippert, Cameron A., Kun Liu, Moushumi Sarma, Sean R. Parkin, Joseph E. Remias, Christine M. Brandewie, Susan A. Odom et Kunlei Liu. « Improving carbon capture from power plant emissions with zinc- and cobalt-based catalysts ». Catal. Sci. Technol. 4, n^o 10 (2014) : 3620–25. http://dx.doi.org/10.1039/c4cy00766b.

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A carbonic anhydrase mimic converting CO₂ to carbonic acid, deprotonated under highly basic conditions, and being converted to a carbamate upon reaction with monoethanolamine, a solvent reported for carbon capture reactions.

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