ABSTRACT
This chapter shows how the terminal phosphate group of ATP may be transferred to a second molecule which is a phosphate-acceptor. During the course of this reaction, ATP is transformed into ADP. The latter, in turn, can “recapture” a phosphate group to give ATP after transfer of a phosphate rest from a phosphate-donor species. The Gibbs energy of hydrolysis of ATP is clearly higher than that of simple esters, glycosides and amids. The values of the Gibbs energies of hydrolysis permit to classify the phosphorylated compounds as being endowed with high phosphate group transfer potential or with low phosphate group transfer potential. ATP is a carrier of chemical energy. It transports chemical energy from high-energy donors to low-energy phosphate acceptors. ATP cannot solely be a phosphoryl group transfer but, is also a pyrophosphoryl and an adenylyl group provider.
