Carbonic Anhydrase Isozymes Research Articles

Carbonic anhydrase, water dissociation and physiology of Kidney.

Carbonic anhydrase (CA) is a zinc metalloenzyme widely distributed throughout the tissues of the body. In the kidney, this enzyme is thought to play a pivotal role in urinary acidification and bicarbonate reabsorption. Two distinct isozymes of carbonic anhydrase have now been identified in the mammalian kidney. A soluble cytoplasmic form, similar if not identical to human erythrocyte carbonic anhydrase C, accounts for the bulk of the renal carbonic anhydrase activity.

Novel benzenesulfonamide-aroylhydrazone conjugates as carbonic anhydrase inhibitors that induce MAPK/ERK-mediated cell cycle arrest and mitochondrial-associated apoptosis in MCF-7 breast cancer cells

A series of novel 4-alkylthio-2-chloro-5-[(2-arylmethylidene)hydrazinecarbonyl]benzenesulfonamide derivatives 3–22 were synthesized and evaluated for their inhibitory activity against human carbonic anhydrase isozymes hCA I, hCA II, hCA IX, and hCA XII. These compounds showed varying degrees of activity against the studied isoenzymes. However, the importance of substituent choice in designing potent carbonic anhydrase inhibitors is highlighted by the strong inhibition profiles of compounds 3 and 10 against hCA IX and the low average KI values for compounds 9 and 10 (134 nM and 77 nM, respectively). All the synthesized compounds were evaluated for their antiproliferative activity toward HeLa, HCT-116, and MCF-7 cell lines. Compounds 9 and 19 exhibited significant activity, particularly against the MCF-7 cell line (IC50 values of 4 μM and 6 μM, respectively). Notably, compound 9 demonstrated a high selectivity index (SI = 8.2) for MCF-7 cells. The antiproliferative effects of compounds 9 and 19 were linked to the induction of cell cycle arrest and apoptosis via the mitochondrial pathway and involved the activation of the MAPK/ERK signaling pathway. Inhibition of MAPK/ERK activity reduced the compounds’ ability to induce cell cycle arrest and apoptosis, indicating the critical role of this pathway. These findings suggest that compounds 9 and 19 are promising candidates for further development as specific and potent anticancer agents targeting the MAPK/ERK pathway.

Glucoimines incorporating classical and non-classical carbonic anhydrase pharmacophores: Design, synthesis, conformational analysis, biological evaluation, and docking simulations

In this report, a series of glucoimines has been prepared by reaction of d-glucosamine and aromatic aldehydes incorporating classical and non-classical carbonic anhydrase pharmacophores. The conformational behavior of veratrole glucoimine was studied in solution and in crystalline form, by NMR and X-ray diffraction analysis, which revealed that pyranose ring adopted a 4C1 conformation. All glucoimines were tested against four isozymes of carbonic anhydrase: hCAs I and II (cytosolic, ubiquitous isozymes) and hCAs IX and XII (tumor-associated isozymes). In this study, per-O-acetylated and deprotected sulfonamide were identified as potent inhibitors of tumor-associated carbonic anhydrase isoforms. Molecular docking simulation was performed inside the active site of hCA II to evaluate the binding modes of veratrole and sulfonamide glucoimines. The last ones demonstrated the most favorable docking scores, indicating strong binding affinity towards hCAII in correlation with experimental inhibition activities. Interestingly, interaction analyses revealed distinct binding modes for ligand-hCAII complexes primarily due to the sulfonamide group.

Investigating Active Site Binding of Ligands to High and Low Activity Carbonic Anhydrase Enzymes Using Native Mass Spectrometry.

Carbonic anhydrases (CAs) are a family of enzymes that play an important pH regulatory role in health and disease. While different CA isozymes have a high degree of structural similarity, they have variable enzymatic activity, with CA III being the least active and having less than 1% of the activity of CA II, the most active. Furthermore, ligand binding studies for CA III are limited, and a resulting lack of chemical probes impedes understanding of this CA isozyme in comparison to other CA family members where studies are abundant. Therefore, we employed native mass spectrometry (nMS), also known as intact mass spectrometry, to assess ligand binding to CA II and CA III and discovered two novel compounds that for the first time display strong binding to CA III. We present a new data visualization and quantification tool developed to display native mass spectra as an intuitive stacked heat map representation for rapidly interpreting the results of ligand-protein binding from nMS screening.

Exploring the Redox and pH Dimension of Carbonic Anhydrases in Cancer: A Focus on Carbonic Anhydrase 3.

Significance: Both redox and pH are important regulatory processes that underpin cell physiological functions, in addition to influencing cancer cell development and tumor progression. The thioredoxin (Trx) and glutathione redox systems and the carbonic anhydrase (CA) proteins are considered key regulators of cellular redox and pH, respectively, with components of the Trx system and CAs regarded as cancer therapeutic targets. However, the redox and pH axis in cancer cells is an underexplored topic of research. Recent Advances: Structural studies of a CA family member, CA3, localized two of its five cysteine residues to the protein surface. Redox-regulated modifications to CA3 have been identified, including glutathionylation. CA3 has been shown to bind to other proteins, including B cell lymphoma-2-associated athanogene 3, and squalene epoxidase, which can modulate autophagy and proinflammatory signaling, respectively, in cancer cells. Critical Issues: CA3 has also been associated with epithelial-mesenchymal transition processes, which promote cancer cell metastasis, whereas CA3 overexpression activates the phosphatidylinositol-3 kinase/protein kinase B/mammalian target of rapamycin (PI3K/AKT/mTOR) pathway, which upregulates cell growth and inhibits autophagy. It is not yet known if CA3 modulates cancer progression through its reported antioxidant functions. Future Directions: CA3 is one of the least studied CA isozymes. Further studies are required to assess the cellular antioxidant role of CA3 and its impact on cancer progression. Identification of other binding partners is also required, including whether CA3 binds to Trx in human cells. The development of specific CA3 inhibitors will facilitate these functional studies and allow CA3 to be investigated as a cancer therapeutic target.

From X-ray crystallographic structure to intrinsic thermodynamics of protein-ligand binding using carbonic anhydrase isozymes as a model system.

Carbonic anhydrase (CA) was among the first proteins whose X-ray crystal structure was solved to atomic resolution. CA proteins have essentially the same fold and similar active centers that differ in only several amino acids. Primary sulfonamides are well defined, strong and specific binders of CA. However, minor variations in chemical structure can significantly alter their binding properties. Over 1000 sulfonamides have been designed, synthesized and evaluated to understand the correlations between the structure and thermodynamics of their binding to the human CA isozyme family. Compound binding was determined by several binding assays: fluorescence-based thermal shift assay, stopped-flow enzyme activity inhibition assay, isothermal titration calorimetry and competition assay for enzyme expressed on cancer cell surfaces. All assays have advantages and limitations but are necessary for deeper characterization of these protein-ligand interactions. Here, the concept and importance of intrinsic binding thermodynamics is emphasized and the role of structure-thermodynamics correlations for the novel inhibitors of CA IX is discussed - an isozyme that is overexpressed in solid hypoxic tumors, and thus these inhibitors may serve as anticancer drugs. The abundant structural and thermodynamic data are assembled into the Protein-Ligand Binding Database to understand general protein-ligand recognition principles that could be used in drug discovery.

Synthesis and DFT-optimized structures of hydrazonal-based compound: Biological activity and molecular docking

Distinctive quinolinyl hydrazonal-based compound was synthesized by an azo-coupling reaction of an enaminonitrile (piperidinylacrylonitrile) with the diazonium salt of 8-aminoquinoline. The synthesized compound was characterized by different spectroscopic methods and displayed distinctive solvatochromism. The possible tautomeric transformation of the arylhydrazonal was studied using DFT quantum chemical calculations revealing that the E→Z tautomerization was a spontaneous exothermic process and its equilibrium constant (Keq) was high with positive power. Thus, the Z-tautomer is more favorable than E-tautomer. This study looks at arylhydrazonal's multiple biological actions, showing its substantial promise in antibacterial, antifungal, anticancer, and enzyme inhibition applications. The arylhydrazonal exhibited concentration-dependent strong antibacterial action against Gram-positive and negative bacteria. Moreover, it showed a comparable concentration-dependent antifungal efficiency against C. albicans and A. fumigatus, and close to fluconazole's potency against A. fumigatus. The arylhydrazonal exhibits significant anticancer action, targeting skin and breast cancer cells, suggesting lesser harm to normal cells. In comparison with acetazolamide (AZA), It inhibited carbonic anhydrase isozymes IX and XII with substantial potency against CA-XII. Molecular docking investigations demonstrated the compound's interactions with proteins such 1D2S, 1AS0, 4WW8, and 5Fl4, revealing different binding energies, RMSD values, and stable configurations via hydrogen bonding and π-H stacking interactions. These results highlight the compound's potential as a therapeutic agent in a variety of clinical applications, calling for more study into its development and clinical usage.

Inhibitor binding to metal-substituted metalloenzyme: Sulfonamide affinity for carbonic anhydrase IX

Transition metal ions are structural and catalytic cofactors of many proteins including human carbonic anhydrase (CA), a Zn-dependent hydrolase. Sulfonamide inhibitors of CA recognize and form a coordination bond with the Zn ion located in the active site of the enzyme. The Zn ion may be removed or substituted with other metal ions. Such CA protein retains the structure and could serve as a tool to study metal ion role in the recognition and binding affinity of inhibitor molecules. We measured the affinities of selected divalent transition metal ions, including Mn, Fe, Co, Ni, Cu, Cd, Hg, and Zn to metal-free CA isozymes CA I, CA II, and CAIX by fluorescence-based thermal shift assay, prepared metal-substituted CAs, and determined binding of diverse sulfonamide compounds.Sulfonamide inhibitor binding to metal substituted CA followed a U-shape pH dependence. The binding was dissected to contributing binding-linked reactions and the intrinsic binding reaction affinity was calculated. This value is independent of pH and protonation reactions that occur simultaneously upon binding native CA and as demonstrated here, to metal substituted CA. Sulfonamide inhibitor binding to cancer-associated isozyme CAIX diminished in the order: Zn > Co > Hg > Cu > Cd > Mn > Ni. Energetic contribution of the inhibitor-metal coordination bond was determined for all above metals. The understanding of the principles of metal influence on ligand affinity and selectivity should help design new drugs targeting metalloenzymes.

Benzothiadiazinone-1,1-Dioxide Carbonic Anhydrase Inhibitors Suppress the Growth of Drug-Resistant Mycobacterium tuberculosis Strains.

2H-Benzo[e][1,2,4]thiadiazin-3(4H)-one 1,1-dioxide (BTD) based carbonic anhydrase (CA) inhibitors are here explored as new anti-mycobacterial agents. The chemical features of BTD derivatives meet the criteria for a potent inhibition of β-class CA isozymes. BTD derivatives show chemical features meeting the criteria for a potent inhibition of β-class CA isozymes. Specifically, three β-CAs (MtCA1, MtCA2, and MtCA3) were identified in Mycobacterium tuberculosis and their inhibition was shown to exert an antitubercular action. BTDs derivatives 2a-q effectively inhibited the mycobacterial CAs, especially MtCA2 and MtCA3, with Ki values up to a low nanomolar range (MtCA3, Ki = 15.1-2250 nM; MtCA2, Ki = 38.1-4480 nM) and with a significant selectivity ratio over the off-target human CAs I and II. A computational study was conducted to elucidate the compound structure-activity relationship. Importantly, the most potent MtCA inhibitors demonstrated efficacy in inhibiting the growth of M. tuberculosis strains resistant to both rifampicin and isoniazid-standard reference drugs for Tuberculosis treatment.

Novel sulfonamide-phosphonate conjugates as carbonic anhydrase isozymes inhibitors.

The three-components one-pot Kabachnik-Fields reaction of sulfapyridine, diethyl phosphite, and aldehyde under thermal catalysis reaction condition in the presence of bismuth (III) triflate as a catalyst afford the corresponding sulfonamide-phosphonates (3a-3p) in good to excellent yields (78%-91%). The structures of the new synthesized compounds were elucidated and confirmed by variable spectroscopic studies. Single crystal X-ray studies for 3a, 3d, and 3i verified the proposed structure. The newly developed sulfonamide-phosphonates were evaluated for their inhibitory properties against four isoforms of human carbonic anhydrase (hCA I, II, IX, and XII). The results demonstrated that they exhibited greater potency in inhibiting hCA XII compared to hCA I, II, and IX, with Ki ranging from 5.1 to 51.1 nM. Compounds 3l and 3p displayed the highest potency, exhibiting selectivity ratios of I/XII >298.7 and 8.5, and II/XII ratios of 678.1 and 142.1, respectively. Molecular docking studies were conducted to explore their binding patterns within the binding pocket of CA XII. The results revealed that the sulfonamide NH group coordinated with the Zn2+ ion, and hydrogen bond interactions were observed with residue Thr200. Additionally, hydrophobic interactions were identified between the benzenesulfonamide phenyl ring and Leu198. Compounds 3p and 3l exhibited an additional hydrogen bonding interaction with other amino acid residues. These supplementary interactions may contribute to the enhanced potency and selectivity of these compounds toward the CA XII isoform.

1, 8]-Naphthyridine derivatives as dual inhibitor of alkaline phosphatase and carbonic anhydrase

[1,8]-Naphthyridine derivatives have been reported to possess important biological activities and may serve as attractive pharmacophores in the drug discovery process. [1,8]-Naphthyridine derivatives (1a-1l) were evaluated for inhibitory potential for isozymes of carbonic anhydrase (CA) and alkaline phosphatase (ALP). CAs have been reported to carry out reversible hydration of CO2 into HCO3−, secretion of electrolytes, acid–base regulation, bone resorption, calcification, and biosynthetic reactions. Whereas ALPs hydrolyze monophosphate esters with the release of inorganic phosphate and play an important role in bone mineralization. Both enzymes have been found to be over-expressed and raised functional activities in patients suffering from rheumatoid arthritis. The discovery of dual inhibitors of these enzymes may provide a synergistic effect to cure bone disorders such as rheumatoid arthritis and ankylosing spondylitis. Among the test compounds, the most potent inhibitors for CA-II, CA-IX, and CA-XII were 1e, 1g, and 1a with IC50 values of 0.44 ± 0.19, 0.11 ± 0.03 and 0.32 ± 0.07 µM, respectively. [1,8]-Naphthyridine derivatives (1a–1l) were approximately 4 folds more potent than standard CA inhibitor acetazolamide. While in the case of ALPs, the most potent compounds for b-TNAP and c-IAP were 1b and 1e with IC50 values of 0.122 ± 0.06 and 0.107 ± 0.02 µM, respectively. Thus, synthesized derivatives proved to be 100 to 800 times more potent as compared to standard inhibitors of b-TNAP and c-IAP (Levamisole and L-phenyl alanine, respectively). In addition, selectivity and dual inhibition of [1,8]-Naphthyridine derivatives confer precedence over known inhibitors. Molecular docking and molecular simulation studies were also conducted in the present studies to define the type of interactions between potential inhibitors and enzyme active sites.

Antispasmodic Effect of Alstonia boonei De Wild. and Its Constituents: Ex Vivo and In Silico Approaches.

Alstonia boonei, belonging to the family Apocynaceae, is one of the best-known medicinal plants in Africa and Asia. Stem back preparations are traditionally used as muscle relaxants. This study investigated the antispasmodic properties of Alstonia boonei Stem back and its constituents. The freeze-dried aqueous Stem back extract of A. boonei, as well as dichloromethane (DCM), ethyl acetate, and aqueous fractions, were evaluated for their antispasmodic effect via the ex vivo method. Two compounds were isolated from the DCM fraction using chromatographic techniques, and their antispasmodic activity was evaluated. An in silico study was conducted by evaluating the interaction of isolated compounds with human PPARgamma-LBD and human carbonic anhydrase isozyme. The Stem back crude extract, DCM, ethyl acetate, and aqueous fractions showed antispasmodic activity on high-potassium-induced (K+ 80 mM) contractions on isolated rat ileum with IC50 values of 0.03 ± 0.20, 0.02 ± 0.05, 0.03 ± 0.14, and 0.90 ± 0.06 mg/mL, respectively. The isolated compounds from the DCM fraction were β-amyrin and boonein, with only boonein exhibiting antispasmodic activity on both high-potassium-induced (IC50 = 0.09 ± 0.01 µg/mL) and spontaneous (0.29 ± 0.05 µg/mL) contractions. However, β-amyrin had a stronger interaction with the two proteins during the simulation. The isolated compounds boonein and β-amyrin could serve as starting materials for the development of antispasmodic drugs.

Synthesis, molecular modeling, and anticancer activity of new thiophene and thiophene-pyrazole analogues incorporating benzene-sulfonamide moiety as carbonic anhydrase isozymes (CA-IX and CA-XII)

Two series of new substituted thiophene and their corresponding thiophene-pyrazole analogues-based benzene-sulfonamide were synthesized and characterized by various spectral data. The DFT/B3LYP methodology was applied to explore the structural and energetic properties of the frontier molecular orbitals of the synthesized compounds. The geometrically optimized structure of the investigated derivatives presented a very resemble structures where the central ring, thiophene, have a planar configuration and its amine or methyl substituent was almost coplanar. Thus, the studied derivatives exhibited comparable energy gap (ΔEH-L), 1.11–2.41 eV, and may be arranged as 3b < 6b < 2b < 5b = 3a < 6a < 2a < 5a. Inspired the well-established anticancer activity of sulfonamide compounds, the newly isolated derivatives were examined against MCF-7, Volo and HepG2 cell lines, as well as, standard fibroblast cells (WI38), using Doxorubicin as reference drug. The data indicated that thiophene and thiophene-pyrazole analogues were more potent toward the VoLo cell line than the others. The 5a, 2b and 6a hybrids exhibited comparable cytotoxic effectiveness against Volo, MCF-7 and HepG2, respectively. Moreover, the inhibitory effect of the synthesized analogues on the cancer-associated carbonic anhydrases, CA-IX and CA-XII, using acetazolamide (AZA) as a reference, were explored. Both 2a and 3a displayed eminent effect on CA-IX while 6a and 6b showed good activity against the CA-XII. Additionally, the newly synthesized thiophene analogues were docked against the crystal construction of (PDB: 3mhc) as a representative protein for CA-XII isozyme.

PLBD: protein-ligand binding database ofthermodynamic andkinetic intrinsic parameters.

We introduce a protein-ligand binding database (PLBD) that presents thermodynamic and kinetic data of reversible protein interactions with small molecule compounds. The manually curated binding data are linked to protein-ligand crystal structures, enabling structure-thermodynamics correlations to be determined. The database contains over 5500 binding datasets of 556 sulfonamide compound interactions with the 12 catalytically active human carbonic anhydrase isozymes defined by fluorescent thermal shift assay, isothermal titration calorimetry, inhibition of enzymatic activity and surface plasmon resonance. In the PLBD, the intrinsic thermodynamic parameters of interactions are provided, which account for the binding-linked protonation reactions. In addition to the protein-ligand binding affinities, the database provides calorimetrically measured binding enthalpies, providing additional mechanistic understanding. The PLBD can be applied to investigations of protein-ligand recognition and could be integrated into small molecule drug design. Database URL https://plbd.org/.

Inhibition Studies on Carbonic Anhydrase Isoforms I, II, IX, and XII with a Series of Sulfaguanidines.

Two novel sulfaguanidine series, six N-(N,N'-dialkyl/dibenzyl-carbamimidoyl) benzenesulfonamide derivatives and nine N-(N-alkyl/benzyl-carbamimidoyl) benzenesulfonamide derivatives, were obtained by desulfidative amination of easily accessible dimethyl arylsulfonylcarbonimidodithioates under catalyst- and base-free conditions. The newly synthesized compounds were tested for the inhibition of four different isozymes of human carbonic anhydrase (hCA I, II, IX and XII, EC 4.2.1.1). Both series reported here were inactive against the off-target isozymes hCA I and II (Ki >100 μM). Interestingly, all investigated compounds inhibited both target isozymes hCA IX and XII in the submicromolar to micromolar ranges in which Ki values spanned from 0.168 to 0.921 μM against hCA IX and from 0.335 to 1.451 μM against hCA XII. The results indicated that N-(N-alkyl/benzyl-carbamimidoyl) benzenesulfonamides were slightly more potent inhibitors than N-(N,N'-dialkyl/dibenzyl-carbamimidoyl) benzenesulfonamides. Among the evaluated compounds, N-n-octyl-substituted N-carbamimidoylbenzenesulfonamide showed the most significant activity with a Ki value of 0.168 μM against hCA IX, which was four-fold more selective toward this isozyme versus hCA XII. Again, another derivative from N-(N-alkyl/benzyl-carbamimidoyl) benzenesulfonamide series, N-p-methylbenzyl-substituted N-carbamimidoylbenzenesulfonamide, demonstrated superior inhibitory activity against hCA XII with a Ki value of 0.335 μM.

Synthesis, characterization and biological evaluation of pyrazole-based benzene sulfonamides as inhibitors of human carbonic anhydrase II, IX and XII.

The aberrant level of the carbonic anhydrase isozymes is linked with various disorders which include glaucoma, epilepsy, altitude sickness and obesity. In the present study, a series of the pyrazole-based benzene sulfonamides derivatives (4a-4l) were designed, synthesized and evaluated as the inhibitors of the three isoforms of human carbonic anhydrases (hCAII, hCAIX and hCAXII). A number of the derivatives were found more active inhibitors than acetazolamide used as a standard against the human hCAII, hCAIX and hCAXII. Among the series, the compound 4k inhibited the hCAII to a submicromolar level presenting the IC50 ± SEM concentration of 0.24 ± 0.18 μM, the inhibitor 4j reduced the activity of the hCAIX to the IC50 ± SEM equals 0.15 ± 0.07 μM, whereas, the molecule 4g blocked the catalytic potential of the isozyme hCAXII with as low as IC50 concentration of 0.12 ± 0.07 μM. In addition, compounds 4e and 4k were screened as the preferential inhibitors of the isoform hCAXII as compared to the hCAIX and hCAXII with half of the maximal concentrations of 0.75 ± 0.13 μM, and 0.24 ± 0.18 μM, respectively. Moreover, the compounds 4k, 4j and 4g were docked inside the active pocket of the crystallographic structure of the isoforms hCAXII, hCAIX and hCAXII, respectively. The docked inhibitors showed the binding interactions with the important amino acid residues such as Leu1198, Thr1199, His1094, and Phe1131 in hCAXII isozyme; residues Val121, Thr200, Pro203, and Gln71 in hCAIX; the amino acids Val119, Leu197, Gln89, and Asn64 in the case of hCAXII. In addition, structural geometries, reactivity descriptors, optimization energy and electronic parameters were calculated to predict the activity of the synthesized compounds.

Chalcogen Bond as a Factor Stabilizing Ligand Conformation in the Binding Pocket of Carbonic Anhydrase IX Receptor Mimic.

It is postulated that the overexpression of Carbonic Anhydrase isozyme IX in some cancers contributes to the acidification of the extracellular matrix. It was proved that this promotes the growth and metastasis of the tumor. These observations have made Carbonic Anhydrase IX an attractive drug target. In the light of the findings and importance of the glycoprotein in the cancer treatment, we have employed quantum-chemical approaches to study non-covalent interactions in the binding pocket. As a ligand, the acetazolamide (AZM) molecule was chosen, being known as a potential inhibitor exhibiting anticancer properties. First-Principles Molecular Dynamics was performed to study the chalcogen and other non-covalent interactions in the AZM ligand and its complexes with amino acids forming the binding site. Based on Density Functional Theory (DFT) and post-Hartree-Fock methods, the metric and electronic structure parameters were described. The Non-Covalent Interaction (NCI) index and Atoms in Molecules (AIM) methods were applied for qualitative/quantitative analyses of the non-covalent interactions. Finally, the AZM-binding pocket interaction energy decomposition was carried out. Chalcogen bonding in the AZM molecule is an important factor stabilizing the preferred conformation. Free energy mapping via metadynamics and Path Integral molecular dynamics confirmed the significance of the chalcogen bond in structuring the conformational flexibility of the systems. The developed models are useful in the design of new inhibitors with desired pharmacological properties.

Synthesis of 4-hydroxy-L-proline derivatives as new non-classical inhibitors of human carbonic anhydrase II activity: an in vitro study

Carbonic anhydrase (CA) is a zinc metalloenzyme that facilitates the rapid conversion of water and carbon dioxide into proton and bicarbonate ion. CA isozymes have been broadly studied in many pathological/physiological processes. In the current research, a series of 4-hydroxy-L-proline derivatives were designed and chemically synthetized, and interaction of these carboxylic acid-based compounds with hCA II were evaluated. Results indicated that different derivatives had different potencies on hCAII inhibitory activity and among them, compounds 3 b and 3c had the lowest IC50 and K d values than 4-hydroxy-L-proline and other derivatives and therefore had the most affinity to the hCA II enzyme. As a result, compounds 3 b and 3c were chosen for additional testing in this research. The Kinetic data demonstrated that 3 b and 3c inhibit the hCA II esterase activity in a linear competitive way, with K i values in the low micromolar range. Fluorescence tests showed that the hCA II surface hydrophobicity is diminished in the presence of compounds 3 b and 3c, as confirmed by the decrease in ANS binding to hCA II in their presence. Docking results revealed that 3 b and 3c had more binding energy than 4-hydroxy-L-proline. Furthermore, these compounds could occupy the active site of hCA II, where they would interact with critical amino acid residues via non-covalent forces to inhibit hCA II. Overall, the strengthening of inhibitory activity and the binding power of these carboxylic acid derivatives (3 b and 3c) for the hCA II makes these compounds interesting for designing novel hCA II inhibitors. Communicated by Ramaswamy H. Sarma

Correlation between Carbonic Anhydrase Isozymes and the Evolution of Myocardial Infarction in Diabetic Patients.

Simple SummaryHeart disease in diabetics presents distinctive characteristics both anatomically and physiopathologically compared to non-diabetics. In people with diabetes, high blood pressure has a high incidence (approximately one-third of diabetic patients have high blood pressure) and is a risk factor for diabetic macro- and microvascular complications. The correlation of these parameters could represent early markers of the prognosis and evolution of diabetic patients with acute myocardial infarction and their routine determination could be included in the biological algorithm of acute myocardial infarction, but understanding of this aspect must be deepened in the future. The results showed that diabetic patients develop acute myocardial infarction more frequently, regardless of age. The level of the enzymes of myocardial necrosis was higher in diabetics compared to non-diabetics, and acute coronary syndrome occurs mainly in diabetics with inadequate metabolic balance. Our research may provide useful information for the medical community.(1) Background: Myocardial infarction was, until recently, recognized as a major coronary event, often fatal, with major implications for survivors. According to some authors, diabetes mellitus is an important atherogenic risk factor with cardiac determinations underlying the definition of the so-called “diabetic heart”. The present study aims to establish a correlation between the evolution of myocardial infarction in diabetic patients, by determining whether lactic acid levels, the activity of carbonic anhydrase isoenzymes, and the magnitude of ST-segment elevation are correlated with the subsequent evolution of myocardial infarction. (2) Methods: The study analyzed 2 groups of 30 patients each: group 1 consisted of diabetic patients with acute myocardial infarction, and group 2 consisted of non-diabetic patients with acute myocardial infarction. Patients were examined clinically and paraclinical, their heart markers, lactic acid, and the activity of carbonic anhydrase I and II isozymes were determined. All patients underwent electrocardiogram and echocardiography analyses. (3) Results: The results showed that diabetics develop acute myocardial infarction more frequently, regardless of how much time has passed since the diagnosis. The value of myocardial necrosis enzymes was higher in diabetics than in non-diabetics, and acute coronary syndrome occurs mainly in diabetics with poor metabolic balance. Lethality rates in non-diabetic patients with lactic acid values above normal are lower than in diabetics. (4) Conclusions: Lactic acid correlated with the activity of isozyme I of carbonic dioxide which could be early markers of the prognosis and evolution of diabetic patients with acute myocardial infarction.

Beta and Gamma Amino Acid-Substituted Benzenesulfonamides as Inhibitors of Human Carbonic Anhydrases.

A series of novel benzenesulfonamide derivatives were synthesized bearing para-N β,γ-amino acid or para-N β-amino acid and thiazole moieties and their binding to the human carbonic anhydrase (CA) isozymes determined. These enzymes are involved in various illnesses, such as glaucoma, altitude sickness, epilepsy, obesity, and even cancer. There are numerous compounds that are inhibitors of CA and used as pharmaceuticals. However, most of them bind to most CA isozymes with little selectivity. The design of high affinity and selectivity towards one CA isozyme remains a significant challenge. The beta and gamma amino acid-substituted compound affinities were determined by the fluorescent thermal shift assay and isothermal titration calorimetry for all 12 catalytically active human carbonic anhydrase isozymes, showing the full affinity and selectivity profile. The structures of several compounds were determined by X-ray crystallography, and the binding mode in the active site of CA enzyme was shown.