ubiquitin-like protein transferase activity ubiquitin-like protein ligase activity 2014-11-06T13:46:23Z E3 small conjugating protein ligase activity GO:0061659 Catalysis of the transfer of a ubiquitin-like protein (ULP) to a substrate protein via the reaction X-ULP + S = X + S-ULP, where X is either an E2 or E3 enzyme, the X-ULP linkage is a thioester bond, and the S-ULP linkage is an isopeptide bond between the C-terminal glycine of ULP and the epsilon-amino group of lysine residues in the substrate. dph molecular_function