It is often stated that the phosphate bonds in atp are "high energy," but in fact, they are not notably high in energy. rather,
they are easy to break, and the δg of hydrolysis is a "useful" quantity of energy. what makes the phosphate bonds easy to break? negative charges on phosphate groups repel each other. positive charges on amino groups repel each other. high acidity attacks bonds between amino acids. high alkalinity attacks bonds between phosphate groups. they are close to the destabilizing nitrogenous base adenosine.
The answer is Negative charges on phosphate groups repel each other. The oxygen groups of a phosphoanhydride in ATP have electron cloud that repels each other. On hydrolysis, once a phosphate is lost, the electrostatic repulsion is reduced.
When ATP is hydrolyzed, it forms more hydrogen bonds with surrounding water molecules that when ATP is unhydrolyzed. Therefore, more energy is released since more bonds are formed than are broken. The net delta G is positive during hydrolysis of ATP.
