Thermodynamic analysis of catalysis by the dihydroorotases from hamster and Bacillus caldolyticus, as compared with the uncatalyzed reaction

An analysis presents a comparison of the catalytic properties of the dihydroorotases (DHOase) from the thermophile Bacillus caldolyticus and that from hamster, which demonstrates the effect of high temperatures on the thermophilic enzyme. The results reveal that the rate enhancement, as well as the transition state affinity of the hamster DHOase increases with a decrease in the temperature because of the electrostatic interactions in the transition state that is absent in the complex in the ground state.