theoretical thermodynamic study on inhibition mechanism of α-humancarbonic anhydrase enzyme by new class of benzenesulfonamides inhibitors

In the present research, the inhibition power of benzenesulfonamides and their urea-derivativescompared to the acetazolamide as the reference drug in inhibition of the carbonic anhydraseenzyme model, isoform (ix), has been investigated using quantum mechanical calculations. allquantum calculations have been performed using density functional theory (dft) using b3lypmodel and 6-311+g** basis set at 298.15 k temperature and 1 atm pressure. in the first step, allfour studied inhibitors were optimized in both gas and solvent phase using pcm method andthen in order to investigate the effect of the inhibition power to inhibit the carbonic anhydraseenzyme, the anionic form of the inhibitors were constructed to interact with the active site of theenzyme model to create the enzyme-inhibitor complex. in the next step, all thermodynamicfunctions such as deprotonation enthalpy of inhibitors (∆hdp), gibbs free energy (∆grxn),standard entropy of reaction (∆srxn) and reaction enthalpy (∆hrxn) were calculated. according tothe calculated results, the values of ∆grxn and ∆hrxn are negative for all four studied complexesand therefore the total reaction is exothermic and spontaneously.