Quantum-Chemical Modelling of Adenosine Triphosphate Hydrolysis in Water Medium

The hydrolysis of adenosine triphosphate to adenosine diphosphate and orthophosphate was simulated using the density functional method. Two systems were considered: an adenosine triphosphate molecule in an aqueous solution and reaction products (adenosine diphosphate, orthophosphate, and H+) uniformly surrounded by water ( $${{n}_{{{{{\text{H}}}_{{\text{2}}}}{\text{O}}}}}$$ = 80). Calculations have shown that the hydrolysis of adenosine triphosphate is accompanied by a decrease in the total energy of the system, which is consistent with the ideas of the energy-donor nature of the reaction of hydrolysis of adenosine triphosphate to adenosine diphosphate and orthophosphate. In the absence of divalent cations, the decrease in energy as a result of adenosine triphosphate hydrolysis is ΔE = EADP+Pi − EATP ≈ −110 kJ/mol. Electrostatic interactions due to the presence of divalent cations (Mg2+ or Ca2+) increase the energy of hydrolysis (ΔE ≈ −135 kJ/mol). The results obtained are discussed in the context of the energy role of adenosine triphosphate in biological systems.