. "Requires mercaptoethanol and a univalent cation." . "Peptides and proteins containing an N-terminal glutamate, aspartate or cystine residue can act as acceptors." . . . "Arginyltransferase" . "Arginyl-tRNA--protein transferase" . "L-arginyl-tRNA + protein = tRNA + L-arginyl-protein." .