The computed EVB free energy barrier for the PT-NA (acylation step) reaction is 23.4 kcal mol -1 , aligning closely with the experimental value of 21.9 kcal•mol -1 . The reaction free energy for the enzyme-catalyzed reaction is exergonic, registering at -1.7 kcal•mol - 1 . Both the experimental and calculated kinetic parameters for the enzyme-catalyzed reaction are listed in Table .