1 1ZB N-[(1s)-1-benzyl-3-diazen-1-iumylidene-2-oxopropyl]glycinamide 1.000 2 5CR N-acetyl-L-phenylalanine 0.737 3 APF 1,1,1-trifluoro-3-acetamido-4-phenyl butan-2-one(N-acetyl-L-phenylalanyl trifluoromethyl ketone) 0.714 4 3NF N-acetyl-L-tyrosine 0.700