Protein N-lysine methyltransferase that selectively catalyzes the trimethylation of EEF1A at 'Lys-79'. L-lysyl-[protein] + 3 S-adenosyl-L-methionine = 3 H(+) + N(6),N(6),N(6)-trimethyl-L-lysyl-[protein] + 3 S-adenosyl-L-homocysteine Belongs to the class I-like SAM-binding methyltransferase superfamily. EFM5 family. Was originally thought to be an N(6)-adenine-specific DNA methyltransferase based on primary sequence and predicted secondary structure.