The γ-class carbonic anhydrase (CAs, EC 4.2.1.1) from the pathogenic bacterium Vibrio cholerae, VchCAγ, was investigated for its activation with a panel of natural and non-natural amino acids and amines. The enzyme was effectively activated by l-tryptophan, 1-(2-minoethyl)-piperazine and 4-(2-aminoethyl)-morpholine, in the low nanomolar range (KAs 8-71 nM). In contrast, l-/d-Phe, l-/d-DOPA, d-Trp, l-/d-Tyr, 4-amino-l-Phe, histamine, dopamine, serotonin, some pyridyl-alkylamines, as well as l-adrenaline were submicromolar activators (KAs between 0.10 and 0.73 µM). l- and d-His were the least effective VchCAγ activators (KAs of 1.01-14.2 µM). The activation of CAs from bacteria have not been considered to date for possible biomedical applications. It would be of interest to study in more details the role of CA activators in processes connected with the virulence and colonization of the host by pathogenic bacteria, such as Vibrio cholerae, which is highly dependent on the concentration of bicarbonate in tissues.
