The small ubiquitin-related modifier (SUMOylation) system is a conserved. reversible. post-translational protein modification pathway covalently attached to the lysine residues of proteins in eukaryotic cells. and SUMOylation is catalyzed by SUMO-specific activating enzyme (E1). https://www.alarecre.com/NHL-Vegas-Golden-Knights-Black-Background-iPhone-14-Plus-Skin-p42149/