The ligase enzyme is responsible for forming fresh covalent connections between two molecules. Ligases, like other enzymes, have proteins with a target molecule recognition area integrated inside them. This gives the enzymatic process an active location to occur.
Different ligases are used to catalyze different kinds of covalent bonds, such as the carbon-nitrogen, carbon-carbon, and carbon-sulfur bonds. The process is catalyzed by a guanosine-5'-triphosphate or adenosine triphosphate molecule,