Metal-ligated amino acids and peptides as substrates for proteases

Amino acids and peptides carrying a pentaamminecobalt(III) group at the carboxyl terminal have been prepared. It is shown that trypsin and papain accept such compounds as substrates provided the metal complex group is not too close to the enzyme-susceptible peptide bond. The possible applicability of this novel type of substrates in enzymatic peptide synthesis is discussed.