Enzymes that catalyse the ligation of two molecules with concomitant hydrolysis of the pyrophosphate bond in adenosine 5'-triphosphate (ATP) or a similar triphosphate, forming $\ce{C–C}$, $\ce{C–O}$, $\ce{C–S}$, $\ce{P–O}$ or $\ce{C–N}$ bonds. In recombinant DNA technology, ligases covalently join together two sequences of DNA (e.g. host DNA and foreign DNA) by a phosphodiester bond.