“…Cerium(IV) is the only lanthanide with an accessible +4 oxidation state and has enhanced Lewis acid strength imparted by its high positive charge density. Thus, it is not surprising that peptide hydrolysis by Ce IV has consistently been found to be superior in comparison to other lanthanide ions (e.g., La III , Ce III , Pr III , Nd III , Sm III , Eu III , Gd III , Tb III , Dy III , Ho III , Er III , Tm III , Yb III ) [64,65,72,80]. This result can be accounted for by the exceptional ability of Ce IV to activate the peptide amide carbonyl towards nucleophilic attack.…”