ENZYME KINETICS AND MECHANISM

Lina Carmona, Shuyi Chen, Janice Chou, Zhen Gong, Michael Hurley, Frances Jin, Stephanie Lo, Ramya Natarajan, Angela Wu, Derek Yee

Advisor: Dr. Adam G. Cassano
Assistant: Jennifer Gomez

ABSTRACT

This study investigated various positions on the adenine ring of the adenosine molecule which, when altered, would inhibit the enzyme adenosine deaminase ( ADA ) and its reactions. Specifically, the carbons at positions 2 and 6 were modified in this experiment. For exploring position 6 on the ring, both 6-chloroadenosine and N-6-cyclohexyladenosine were used, while 2-chloroadenosine was used for similar consideration of position 2. Using the Michaelis-Menten equation, K m and V max values were determined for adenosine and then compared to that of 6-chloroadenosine, which appeared to act as a substrate rather than as an inhibitor of ADA . The V max value for adenosine at 6.0 x 10 -4 U/mL was found to be 3.6 x 10 -9 µM/s and the K m was calculated to be 5.5 µM. 2-chloroadenosine and N-6-cyclohexyladenosine seemed to act as inhibitors of ADA , as the rate of the deaminase reaction significantly decreased in their presence. 2-chloroadenosine appeared to act as the most effective inhibitor; thus, position 2 should be one possibility further studied for future identification and synthesis of ADA inhibitors.