Inhibition of the R1 fragment of the cadmium-containing ζ-class carbonic anhydrase from the diatom Thalassiosira weissflogii with anions

✍ Scribed by Francesca Viparelli; Simona Maria Monti; Giuseppina De Simone; Alessio Innocenti; Andrea Scozzafava; Yan Xu; François M.M. Morel; Claudiu T. Supuran

• Book ID: 104004604
• Publisher: Elsevier Science
• Year: 2010
• Tongue: English
• Weight: 522 KB
• Volume: 20
• Category: Article
• ISSN: 0960-894X
• DOI: 10.1016/j.bmcl.2010.06.139

✦ Synopsis

We investigated the catalytic activity and inhibition of both the zinc and cadmium-containing R1 fragment of the f-class carbonic anhydrase (CA, EC 4.2.1.1) from the marine diatom Thalassiosira weissflogii. Our data prove that these enzymes are not only very efficient catalysts for the physiological reaction, but also sensitive to sulfonamide and anion inhibitors, with inhibition constants from the nanomolar to millimolar range. Acetazolamide inhibited the two enzymes with K I s in the range of 58-92 nM.

The best anion inhibitors of Cd-R1 were thiocyanate, sulfamate and sulfamide, with K I s of 10-89 lM, whereas the best Zn-R1 anion inhibitors were sulfamate and sulfamide with K I s of 60-72 lM. These enzymes were only weakly inhibited by chloride, bromide or sulfate, main anion components of sea water, with inhibition constants in the range of 0.24-0.85 mM. Thus, similarly to CAs belonging to other classes, the f-class CA (with either cadmium or zinc ions at the active site) was inhibited by both anions and sulfonamides.