A new carbonic anhydrase identified in the Gram-negative bacterium (Chromohalobacter sp.) and the interaction of anions with the enzyme.

In this study, the characterization and inhibition characteristic of α-class carbonic anhydrase from Chromohalobacter (ChCA) was documented for the first time. The carbonic anhydrase enzyme had 47.77% yield and 54.45-fold purity. The specific activity of the enzyme was determined as 318.52 U/mg proteins. Alternative substrate (4-nitrophenyl trifluoroacetate, 4-nitrophenyl phosphate, 4-nitrophenyl sulphate and 4-nitrophenyl acetate) were tested for the enzyme. K and V values for 4-nitrophenyl acetate were 4.57 mM and 4.29 EU/mL and for 4-nitrophenyl trifluoroacetate were 2.39 mM and 2.41 EU/mL. The anions, Cl, NO, NO, Br, ClO, ClO, I, CO and SO, inhibited the ChCA hydratase activity. Among nine anions, the strongest inhibitor activities were obtained with micro molar concentrations of NO, NO, Br, I, CO (K values of 160-255 μM). Other four anions tested (Cl, ClO, ClO and SO) showed moderate inhibitory activities (K values of 680-813.5 μM). The results obtained demonstrate that the anions we tested inhibit the Chromohalobacter CA (ChCA) enzyme as in other α-CAs in mammals; however, the susceptibility of ChCA resulted from anions differed significantly from that of other organism CAs.