L-Arginine and zinc ion effect on recognition and hydrolysis rate of adenosine 5′-triphosphate

Abstract

Zn2+ can interact with adenosine 5′-triphosphate (ATP) by electrostatic and coordination interactions, and the interaction sites between Zn2+ and ATP vary at different pH in the ATP–Zn2+ binary system. Non-covalent interactions exist between the carboxyl of arginine (Arg) and Zn2+, which led to competition between ATP and Arg to interact with Zn2+ in the ATP–Zn2+–Arg ternary system. Kinetics studies show that the hydrolysis rate constant of ATP in the ATP–Zn2+ binary system was 2.44 × 10−2 min−1, about 11-fold faster than that (2.27 × 10−3 min−1) in the ATP–Zn2+–Arg ternary system. This may be attributed to coordination interactions between the carboxyl of Arg and Zn2+ and the decreased activity of zinc ion toward the phosphate groups via nucleophilic attack. A mechanism that the hydrolysis occurred through an addition–elimination mechanism is proposed.