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 = CH2COOH, 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.
