Purification and biochemical characterization of a novel carbonic anhydrase II from erythrocytes of camel (Camelus dromedarius)

A novel carbonic anhydrase II (CA II) from erythrocytes of camel (Camelus dromedarius) was purified to ho-mogeneity using affinity chromatography and biochemically characterized. Specific activity of 140.88 U/mg was obtained with 745.17-fold purification and 25.37% yield. The enzyme was a monomer with a lower molecular weight (25 kDa) and lower Zn content (0.50 mol of Zn per mol of protein). The enzyme showed higher optimum temperature (70 degrees C) and pH (pH 9.0), moreover, it was stable at higher temperatures and strongly alkaline pH as judged by thermodynamic parameters (Ea, kd, Ed, t1/2, D-value, Z-value, & UDelta;H, & UDelta;G and & UDelta;S). The enzyme was inhibited by cations (Al3+, Ca2+, Cd2+, Co2+, Cr3+, Cu2+, Fe3+, Ni2+, Mg2+ and Zn2+) as well as by anions (Br CH3COO affect enzyme activity. Effect of various chemicals on enzyme activity was also investigated. Km, Vmax, kcat and kcat/Km values for 4-NPA were found to be 1.74 mM, 0.0093 U/mL, 0,0039 s  1 and 0,0023 s  1 mM  1, respec-tively. With these interesting biochemical properties, camel CA II represents promising candidate for harsh in-dustrial applications, in particular, for a successful biomimetic CO2 sequestration process. ? ? ? ? ? , ClO4, CN ? , F , HCO3, I ? , N3, ? NO3 and SCN ), some anions (C6H5O73  , CO32  , SeO3 ? , and SO42 ) does not