The ‘energy’ of ATP (more properly its group transfer potential) is in fact the negative free energy of the hydrolysis of ATP to ADP (and orthophosphate), or to AMP (and pyrophosphate). If an enzyme can couple this reaction to another with positive free energy of hydrolysis then it can drive the second reaction. This important point is dealt with in Berg et al. section and it is also worth reading the preceding section. ATP is not a reducing agent so is not limited to oxido-reduction reactions. (The hydrolysis of ATP can also be used to provide . mechanical or electrical or light energy, which is why Berg et al refer to it in section as “…the Universal Currency of Free Energy in Biological Systems”.) In synthetic processes ATP (or other nucleotide triphosphates derived from it) is often used in reactions forming bonds (C–C, peptide, glycosidic, phophodiester). In some of these cases the hydrolysis of the ATP is used to generate an activated form of the basic component, which allows it to form the bond in a subsequent reaction.