Contribution to the study of the enzymatic activity of benzonase

Abstract The hydrolytic activity of benzonase has been studied at different values of Mg(II) concentration, pH, temperature and percentages of water-miscrible organic solvents (DMSO, THF, ACN and DMF). The action of these parameters on the UV spectra of benzonase has been analyzed. The best experimental conditions (pH = 8.0, T = 37 °C, [Mg(II)] = 2 mM) lead to a well-defined conformation. This conformation is active vs. DNA and RNA. Changes in these parameters give conformational alterations which can be monitored by changes in the UV spectra. Organic solvents deactivate the enzyme by hydrophobic interaction of the lipophilic solvent molecules with the aliphatic residues of the protein. DMF, the most hydrophilic solvent tested by us, gives slight deactivation of the enzyme. Benzonase hydrolyzes native DNA, heat-denatured DNA and RNA. The active site seems to be the same in all cases. Benzonase has been immobilized for the first time, retaining high enzymatic activity.