<P> The one exception is of value because it allows a single hydrolysis, ATP + H O → AMP + PP, to effectively supply the energy of hydrolysis of two high - energy bonds, with the hydrolysis of PP being allowed to go to completion in a separate reaction . The AMP is regenerated to ATP in two steps, with the equilibrium reaction ATP + AMP ↔ 2ADP, followed by regeneration of ATP by the usual means, oxidative phosphorylation or other energy - producing pathways such as glycolysis . </P> <P> Often, high - energy phosphate bonds are denoted by the character' ~' . In this "squiggle" notation, ATP becomes A-P ~ P ~ P . The squiggle notation was invented by Fritz Albert Lipmann, who first proposed ATP as the main energy transfer molecule of the cell, in 1941 . It emphasizes the special nature of these bonds . Stryer states: </P> <P> ATP is often called a high energy compound and its phosphoanhydride bonds are referred to as high - energy bonds . There is nothing special about the bonds themselves . They are high - energy bonds in the sense that free energy is released when they are hydrolyzed, for the reasons given above . Lipmann's term "high - energy bond" and his symbol ~ P (squiggle P) for a compound having a high phosphate group transfer potential are vivid, concise, and useful notations . In fact Lipmann's squiggle did much to stimulate interest in bioenergetics . </P> <P> The term' high energy' with respect to these bonds can be misleading because the negative free energy change is not due directly to the breaking of the bonds themselves . The breaking of these bonds, like the breaking of most bonds, is endergonic and consumes energy rather than releasing it . The negative free energy change comes instead from the fact that the bonds formed after hydrolysis - or the phosphorylation of a residue by ATP - are lower in energy than the bonds present before hydrolysis . (This includes all of the bonds involved in the reaction, not just the phosphate bonds themselves). This effect is due to a number of factors including increased resonance stabilization and solvation of the products relative to the reactants . </P>

In which structure atp or adp is more energy stored