title: Characterization and anions inhibition studies of an α-carbonic anhydrase from the teleost fish Dicentrarchus labrax.
abstract: Carbonic anhydrase (CA; EC 4.2.1.1) was purified from the gill of the teleost fish Dicentrarchus labrax (European seabass). The purification procedure consisted of a single step affinity chromatography on Sepharose 4B-tyrosine-sulfanilamide. The enzyme was purified 84.9-fold with a yield of 58%, and a specific activity of 838.9 U/mg proteins. It has an optimum pH at 8.0; an optimum temperature at 10°C. The kinetic parameters of this enzyme were determined for its esterase activity, with 4-nitrophenyl acetate (NPA) as substrate. The following anions, H₂NSO₃⁻, I⁻, SCN⁻, NO₃⁻, NO₂⁻, N₃⁻, Br⁻, Cl⁻, SO₄²⁻, and F⁻ showed inhibitory effects on the enzyme. Sulfamic acid, iodide, and thiocyanate exhibited the strongest inhibitory action, in the micromolar range (K(i)s of 87-187 μM). NO₃⁻, NO₂⁻ and N₃⁻ were moderate inhibitors, whereas other anions showed only weak actions. All tested anions inhibited the enzyme in a competitive manner. Our findings indicate that these anions inhibit the fish enzyme in a similar manner to other α-CAs from mammals investigated earlier, but the susceptibility to various anions differs significantly between the fish and mammalian CAs.
authors.affiliation: Ondokuz Mayis University, Department of Agricultural Biotechnology, Samsun, Turkey. dekinci80@gmail.com
authors.forename: Deniz
authors.initials: D
authors.lastname: Ekinci
authors.forename: Saltuk Buğrahan
authors.initials: SB
authors.lastname: Ceyhun
authors.forename: Murat
authors.initials: M
authors.lastname: Sentürk
authors.forename: Deryanur
authors.initials: D
authors.lastname: Erdem
authors.forename: Omer İrfan
authors.initials: Oİ
authors.lastname: Küfrevioğlu
authors.forename: Claudiu T
authors.initials: CT
authors.lastname: Supuran
mesh_terms: D000818:Animals; D000838:Anions / Q000737:chemistry* / Q000494:pharmacology; D001492:Bass / Q000378:metabolism*; D002257:Carbonic Anhydrase Inhibitors / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology; D002256:Carbonic Anhydrases / Q000737:chemistry* / Q000378:metabolism; D007700:Kinetics; D013451:Sulfonic Acids / Q000737:chemistry / Q000494:pharmacology; D013861:Thiocyanates / Q000737:chemistry / Q000494:pharmacology
chemical_list: D000838:Anions; D002257:Carbonic Anhydrase Inhibitors; D013451:Sulfonic Acids; D013861:Thiocyanates; C005741:sulfamic acid; D002256:Carbonic Anhydrases; C031760:thiocyanate