Synthesis and inhibition potency of novel ureido benzenesulfonamides incorporating GABA as tumor-associated carbonic anhydrase IX and XII inhibitors

<div><p></p><p>New ureido benzenesulfonamides incorporating a GABA moiety as a linker between the ureido and the sulfonamide functionalities were synthesized and their inhibition potency determined against both the predominant cytosolic (hCA I and II) and the transmembrane tumor-associated (hCA IX and XII) isoforms of the metalloenzyme carbonic anhydrase (CA, EC 4.2.1.1). The majority of these compounds were medium potency inhibitors of the cytosolic isoform hCA I and effective hCA II inhibitors, whereas they showed strong inhibition of the two transmembrane tumor-associated isoforms hCA IX and XII, with <i>K_I</i>s in nanomolar range. Only one derivative had a good selectivity for inhibition of the tumor-associated hCA IX target isoform over the cytosolic and physiologically dominant off-target hCA I and II, being thus a potential tool to develop new anticancer agents.</p></div

α‑Carbonic Anhydrases Possess Thioesterase Activity

The α-carbonic anhydrases (CAs, EC 4.2.1.1) show catalytic versatility acting as esterases with carboxylic, sulfonic, and phosphate esters. Here we prove by kinetic, spectroscopic, and MS studies that they also possess thioesterase activity with a dithiocarbamate ester as a substrate (PhSO₂NHCSSMe). Its CA-mediated hydrolysis leads to benzenesulfonamide, methyl mercaptan, and COS. The CA thioesterase activity may be useful for designing prodrug enzyme inhibitors, whereas some CA isoforms may use this activity for modulating physiologic/pathologic processes, which are possibly amenable to drug discovery of agents with multiple mechanisms of action

Molecular Cloning, Characterization, and Inhibition Studies of a β-Carbonic Anhydrase from <i>Malassezia globosa</i>, a Potential Antidandruff Target

A β-carbonic anhydrase (CA, EC 4.2.1.1) from the fungal pathogen <i>Malassezia globosa</i> has been cloned, characterized, and studied for its inhibition with sulfonamides. This enzyme, designated MG-CA, has significant catalytic activity in the CO₂ hydration reaction and was inhibited by sulfonamides, sulfamates, and sulfamides with <i>K</i>_I in the nanomolar to micromolar range. Several sulfonamides have also been investigated for the inhibition of growth of <i>M. globosa</i>, <i>M. dermatis</i>, <i>M. pachydermatic</i>, and <i>M. furfur</i> in cultures, whereas a mouse model of dandruff showed that treatment with sulfonamides led to fragmented fungal hyphae, as for the treatment with ketoconazole, a clinically used antifungal agent. These data prompt us to propose MG-CA as a new antidandruff drug target

Dithiocarbamates Strongly Inhibit Carbonic Anhydrases and Show Antiglaucoma Action in Vivo

A series of dithiocarbamates were prepared by reaction of primary/secondary amines with carbon disulfide in the presence of bases. These compounds were tested for the inhibition of four human (h) isoforms of the zinc enzyme carbonic anhydrase, CA (EC 4.2.1.1), hCA I, II, IX, and XII, involved in pathologies such as glaucoma (CA II and XII) or cancer (CA IX). Several low nanomolar inhibitors targeting these CAs were detected. The X-ray crystal structure of the hCA II adduct with morpholine dithiocarbamate evidenced the inhibition mechanism of these compounds, which coordinate to the metal ion through a sulfur atom from the dithiocarbamate zinc-binding function. Some dithiocarbamates showed an effective intraocular pressure lowering activity in an animal model of glucoma

(A) Schematic representation of the structure of L; the copper ions are depicted as magenta spheres

<p><b>Copyright information:</b></p><p>Taken from "Crystal structure of a blue laccase from : evidences for intermediates in the molecular oxygen reductive splitting by multicopper oxidases"</p><p>http://www.biomedcentral.com/1472-6807/7/60</p><p>BMC Structural Biology 2007;7():60-60.</p><p>Published online 26 Sep 2007</p><p>PMCID:PMC2064922.</p><p></p> (B) T2/T3 trinuclear cluster active site as observed in molecule A of L. (C) Substrate active T1 pocket residues. (D) Stereoview of the schematic representation of the four copper sites in L

Alignment of the L blue laccase amino acid sequence with other laccase sequences

<p><b>Copyright information:</b></p><p>Taken from "Crystal structure of a blue laccase from : evidences for intermediates in the molecular oxygen reductive splitting by multicopper oxidases"</p><p>http://www.biomedcentral.com/1472-6807/7/60</p><p>BMC Structural Biology 2007;7():60-60.</p><p>Published online 26 Sep 2007</p><p>PMCID:PMC2064922.</p><p></p> Lt – laccase [ and Pdb code: ]; Tve – [gi:21730581, pdb:]; Tvi – []; Pc – []; Ft – []; So – laccase [unpublished gene-xray]; Cc – [pdb:]; Rl – [pdb:]; Ts – []; Ma – []; Tov – [] ; Mt – []; Bs – Cota [pdb:]. Positions identical in all sequences are marked with a black background. Regions, in which the sequences are similar are marked with light grey

Schematic representations of different possible adducts of the trinuclear T2/T3 copper cluster

<p><b>Copyright information:</b></p><p>Taken from "Crystal structure of a blue laccase from : evidences for intermediates in the molecular oxygen reductive splitting by multicopper oxidases"</p><p>http://www.biomedcentral.com/1472-6807/7/60</p><p>BMC Structural Biology 2007;7():60-60.</p><p>Published online 26 Sep 2007</p><p>PMCID:PMC2064922.</p><p></p> A and B: 4-electrons reduced dioxygen adducts, C: enzyme resting state

(A) and (B) Representations of the Fo-Fc difference Fourier omit map for the T2/T3 active site of molecules A and B of L respectively, each flanked by the corresponding schematic pictures

<p><b>Copyright information:</b></p><p>Taken from "Crystal structure of a blue laccase from : evidences for intermediates in the molecular oxygen reductive splitting by multicopper oxidases"</p><p>http://www.biomedcentral.com/1472-6807/7/60</p><p>BMC Structural Biology 2007;7():60-60.</p><p>Published online 26 Sep 2007</p><p>PMCID:PMC2064922.</p><p></p> The electron density is contoured at 2.2 σ. (C) Schematic representation of the catalytic mechanism of multicopper oxidases including the intermediates observed in the present structural study and previous spectroscopic, kinetic, and structural investigations

Cloning, Characterization, and Sulfonamide and Thiol Inhibition Studies of an α‑Carbonic Anhydrase from <i>Trypanosoma cruzi</i>, the Causative Agent of Chagas Disease

An α-carbonic anhydrase (CA, EC 4.2.1.1) has been identified, cloned, and characterized from the unicellular protozoan <i>Trypanosoma cruzi</i>, the causative agent of Chagas disease. The enzyme (TcCA) has a very high catalytic activity for the CO₂ hydration reaction, being similar kinetically to the human (h) isoform hCA II, although it is devoid of the His64 proton shuttle. A large number of aromatic/heterocyclic sulfonamides and some 5-mercapto-1,3,4-thiadiazoles were investigated as TcCA inhibitors. The aromatic sulfonamides were weak inhibitors (<i>K</i>_I values of 192 nM to 84 μM), whereas some heterocyclic compounds inhibited the enzyme with <i>K</i>_I values in the range 61.6–93.6 nM. The thiols were the most potent in vitro inhibitors (<i>K</i>_I values of 21.1–79.0 nM), and some of them also inhibited the epimastigotes growth of two <i>T. cruzi</i> strains in vivo

Monothiocarbamates Strongly Inhibit Carbonic Anhydrases in Vitro and Possess Intraocular Pressure Lowering Activity in an Animal Model of Glaucoma

A series of monothiocarbamates (MTCs) were prepared from primary/secondary amines and COS as potential carbonic anhydrase (CA, EC 4.2.1.1) inhibitors, using the dithiocarbamates, the xanthates, and the trithiocarbonates as lead compounds. The MTCs effectively inhibited the pharmacologically relevant human (h) hCAs isoforms I, II, IX, and XII in vitro and showed <i>K</i>_Is spanning between the low and medium nanomolar range. By means of a computational study, the MTC moiety binding mode on the CAs was explained. Furthermore, a selection of MTCs were evaluated in a normotensive glaucoma rabbit model for their intraocular pressure (IOP) lowering effects and showed interesting activity