Molecular function

Catalysis of the transfer of UFM1 to a substrate protein via the reaction X-UFM1 + S = X + S-UFM1, where X is either an E2 or E3 enzyme, the X-UFM1 linkage is a thioester bond, and the S-UFM1 linkage is an isopeptide bond between the C-terminal amino acid of UFM1 and the epsilon-amino group of lysine residues in the substrate.