👉 In biology, a ligase is a protein that catalyzes the addition of a phosphate group to DNA or RNA. These proteins are involved in many processes within cells and can be found in various organisms, including bacteria, plants, and animals. A ligase typically has two active sites: one for the ADP-ribose moiety (a sugar molecule) and another for the phosphate group. The ADP-ribose moiety is responsible for the addition of a phosphate group to DNA