“…13 The incorporation of aliphatic (Val, Nle, Leu, Abu, Cha, and Met) and aromatic (Phe, Tyr(O-Benzyl)) at the P 1 position resulted in compounds with good or moderate calpain I inhibitory activity. 157 Hydrophobic groups will enhance potency while incorporation of amino acids which are capable of hydrogen bonding does not increase potency (such as Ser, Thr, Gln and Tyr) 157 and is detrimental to binding. 13 Aromatic amino acids are less potent than aliphatic amino acids.…”