Source:http://linkedlifedata.com/resource/umls/id/C3268597
GO: Catalysis of the reaction: protein-lysine + protein-lysine = protein N6-(lysyl)-L-lysine + protein. This reaction is the addition of lysine group from one protein to a lysine residue in a second protein, producing N6-(lysyl)-L-lysine. [PMID:20729861]