@article{Mahinpour_Ghasemi_Moosavi-Nejad_Zahraie_2024, title={Caffeine effect on adenosine deaminase catalysis: A new look at the effect of caffeine on adenosine deaminase activity}, volume={6}, url={https://oiccpress.com/iranian-journal-of-catalysis/article/caffeine-effect-on-adenosine-deaminase-catalysis-a-new-look-at-the-effect-of-caffeine-on-adenosine-deaminase-activity/}, abstractNote={The effect of physiological concentrations of caffeine (purified from Persian tea) on adenosine deaminase (ADA) activity at physiological and pathological concentrations of adenosine (as substrate) in 50 mM Tris-HCl buffer (pH 7.3) at 37°C was investigated, using UV-VIS spectroscopy. ADA exhibited a bi-phasic activity behavior and both phases showed positive cooperativities indicating adenosine has at least two regulatory sites on ADA molecule. We proposed a mechanism for the inhibitory effect of caffeine on ADA catalytic activity by analyzing ADA kinetic behavior at various physiological concentrations of caffeine (10, 30, 70 mM): Caffeine dominantly resulted in decreased catalytic activity of ADA via reducing the positive homotropic effect of adenosine on ADA activity. Surprisingly, it also showed a very weak but significant activatory effect on ADA activity in a concentration-dependent manner. To the best of our knowledge, this is the first report on the dual effect of caffeine on ADA activity.  }, number={5}, journal={Iranian Journal of Catalysis}, publisher={OICC Press}, author={Mahinpour, Roya and Ghasemi, Majid and Moosavi-Nejad, Zahra and Zahraie, Zohreh}, year={2024}, month={Feb.}, keywords={Caffeine, Adenosine deaminase, Inhibition, Homotropic effect} }