Val-Gly-Ser-Glu (NSC 350591) is an ECF-A tetrapeptide. Val-Gly-Ser-Glu dose-dependently increases the number of human eosinophils, but not neutrophils, rosetting with complement-coated sheep erythrocytes (EAC3b).

Suc-Leu-Tyr-AMC is a fluorescent substrate for calpain I and II, papain (another cysteine protease), and is used to measure the chymotrypsin-like peptidase activity of the 20S proteasome (excitation max: 360 nm; emission max: 460 nm). Suc-Leu-Tyr-AMC can also be cleaved by the Ti protease from E. coli.

β-Amyloid (40-1) is a biological active peptide. (non-toxic reverse fragment Aβ(40–1)