- Rapid and direct spectrophotometric method for kinetics studies and routine assay of peroxidase based on aniline diazo substrates
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Peroxidases are ubiquitous enzymes that play an important role in living organisms. Current spectrophotometrically based peroxidase assay methods are based on the production of chromophoric substances at the end of the enzymatic reaction. The ambiguity regarding the formation and identity of the final chromophoric product and its possible reactions with other molecules have raised concerns about the accuracy of these methods. This can be of serious concern in inhibition studies. A novel spectrophotometric assay for peroxidase, based on direct measurement of a soluble aniline diazo substrate, is introduced. In addition to the routine assays, this method can be used in comprehensive kinetics studies. 4-[(4-Sulfophenyl)azo]aniline (λ max = 390 nm, ? = 32 880 M?1 cm?1 at pH 4.5 to 9) was introduced for routine assay of peroxidase. This compound is commercially available and is indexed as a food dye. Using this method, a detection limit of 0.05 nmol mL?1 was achieved for peroxidase.
- Mirazizi, Fatemeh,Bahrami, Azita,Haghbeen, Kamahldin,Shahbani Zahiri, Hossein,Bakavoli, Mehdi,Legge, Raymond L.
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p. 1162 - 1169
(2016/10/09)
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- Carbonic anhydrase inhibitors. Diazenylbenzenesulfonamides are potent and selective inhibitors of the tumor-associated isozymes IX and XII over the cytosolic isoforms I and II
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A series of diazenylbenzenesulfonamides, azo-dye derivatives of sulfanilamide or metanilamide incorporating phenol and amine moieties, were tested for inhibition of the tumor-associated isozymes of carbonic anhydrase (CA, EC 4.2.1.1), CA IX and XII. These compounds showed moderate-low inhibitory activities against the cytosolic isoforms CA I and II (offtargets) and excellent, low nanomolar inhibitory activity against the transmembrane CA IX and XII (KIs in the range of 3.5-63 nM against CA IX and 5.0-69.4 nM against CA XII, respectively). The selectivity ratio for inhibiting the tumor-associated CA IX over the offtarget CA II was in the range of 15-104 for these diazenylbenzenesulfonamides, making them among the most isoform-selective inhibitors targeting tumor-associated CAs (over the ubiquitous CA II). Since CA IX/XII were recently shown to be both therapeutic and diagnostic targets for hypoxic solid tumors overexpressing these proteins, such compounds held promise for the management of hypoxic tumors, which are largely non-responsible to classical chemo- and radio-therapy.
- Carta, Fabrizio,Maresca, Alfonso,Scozzafava, Andrea,Vullo, Daniela,Supuran, Claudiu T.
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experimental part
p. 7093 - 7099
(2010/03/03)
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- Carbonic anhydrase inhibitors. Inhibition of the Rv1284 and Rv3273 β-carbonic anhydrases from Mycobacterium tuberculosis with diazenylbenzenesulfonamides
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A series of diazenylbenzenesulfonamides obtained from sulfanilamide or metanilamide by diazotization followed by coupling with phenols or amines, was tested for the inhibition of the β-carbonic anhydrases (CAs, EC 4.2.1.1) encoded by the genes Rv1284 and
- Maresca, Alfonso,Carta, Fabrizio,Vullo, Daniela,Scozzafava, Andrea,Supuran, Claudiu T.
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experimental part
p. 4929 - 4932
(2009/12/24)
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