Carbonic Anhydrase Interaction With Lipothioars Enites: A Novel Class of Isozymes I and II Inhibitors

The interaction of carbonic anhydrase (CA) isozymes I and II with a series of As(III) derivatives, dialkyl and diaryl rac-2,3-dimyristoyloxypropyldithioarsonites, was investigated kinetically and spectrophotometrically, utilizing the native and Co(II)-substituted enzymes. Depending on the substitution pattern at the -As(SR)(2) moiety of the investigated derivatives, inactive compounds were found for R = phenyl or naphthyl, and active ones for derivatives containing carboxyl groups (R = CH(2)COOH, cysteinyl and glutathionyl). Together with the arsonolipids previously investigated, the active compounds of this series - the "lipothioarsenites"- constitute a novel class of CA inhibitors that bind to the metal ion within the enzyme active site, as proved by changes in the electronic spectra of adducts of such inhibitors with Co(II)CA.