Carbonic anhydrase VII is S-glutathionylated without loss of catalytic activity and affinity for sulfonamide inhibitors

• Published in: Bioorganic & medicinal chemistry letters 2012-02, Vol.22 (4), p.1560-1564
• Main Authors: Truppo, Emanuela, Supuran, Claudiu T., Sandomenico, Annamaria, Vullo, Daniela, Innocenti, Alessio, Di Fiore, Anna, Alterio, Vincenzo, De Simone, Giuseppina, Monti, Simona M.
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Biological and medical sciences; CA inhibitors; carbon dioxide; carbonate dehydratase; Carbonic Anhydrase Inhibitors - chemistry; Carbonic Anhydrase Inhibitors - pharmacology; Carbonic anhydrase VII; Carbonic Anhydrases - genetics; Carbonic Anhydrases - metabolism; Catalytic activity; Cysteine reactivity; Cytosol - enzymology; Enzyme Activation - drug effects; esterases; glutathione; Glutathionylation; Humans; Inhibitory Concentration 50; Medical sciences; Molecular Sequence Data; Pharmacology. Drug treatments; Protein Isoforms - genetics; reactive oxygen species; S-Nitrosoglutathione - chemistry; Sequence Alignment; Spectrometry, Mass, Electrospray Ionization; sulfonamides; Sulfonamides - chemistry; Sulfonamides - pharmacology
• ISSN: 0960-894X; 1464-3405
• DOI: 10.1016/j.bmcl.2011.12.134

Human carbonic anhydrase (CA, EC 4.2.1.1) VII is a cytosolic enzyme with high carbon dioxide hydration activity. Here we report an unexpected S-glutathionylation of hCA VII which has also been observed earlier in vivo for hCA III, another cytosolic isoform. Cys183 and Cys217 were found to be the residues involved in reaction with glutathione for hCA VII. The two reactive cysteines were then mutated and the corresponding variant (C183S/C217S) expressed. The native enzyme, the variant and the S-glutathionylated adduct (sgCA VII) as well as hCA III were fully characterized for their CO2 hydration, esterase/phosphatase activities, and inhibition with sulfonamides. Our findings suggest that hCA VII could use the in vivo S-glutathionylation to function as an oxygen radical scavenger for protecting cells from oxidative damage, as the activity and affinity for inhibitors of the modified enzyme are similar to those of the wild type.