. "\"Catalysis of ATP-dependent isopeptide bond formation between the carboxy-terminal residues of a small conjugating protein such as ubiquitin or a ubiquitin-like protein, and a substrate lysine residue. This function may be performed alone or in conjunction with an E3, ubiquitin-like protein ligase.\" [GOC:mah, GOC:rn, PMID:10806345, PMID:10884686]" . . "small conjugating protein ligase activity" . "small protein conjugating enzyme activity" . "Reactome:REACT_75843 \"RIP2 is K63 polyubiquitinated, Homo sapiens\"" . . "E2" . "ubiquitin-like conjugating enzyme activity" . "ubiquitin-like-protein ligase activity" .