Bioactive peptides derived from natural proteins with respect to diversity of their receptors and physiological effects

• We have found various bioactive peptides derived from natural proteins, which interact receptors for endogenous bioactive peptides such as opioid, neurotensin, oxytocin, formyl peptides and complements C3a/C5a etc., and investigated their physiological effects.
• Fom this approach we found new central effects such as memory-consolidating, anxiolytic-like and anorexigenic, and peripheral effects such as hypocholesterolemic and antialopeia, to which receptor for endogenous bioactive peptides are engaged.

We have found various bioactive peptides derived from animal and plant proteins, which interact with receptors for endogenous bioactive peptides such as opioids, neurotensin, complements C3a and C5a, oxytocin, and formyl peptides etc. Among them, rubiscolin, a δ opioid peptide derived from plant RuBisCO, showed memory-consolidating, anxiolytic-like, and food intake-modulating effects. Soymorphin, a μ opioid peptide derived from β-conglycinin showed anxiolytic-like, anorexigenic, hypoglycemic, and hypotriglyceridemic effects. β-Lactotensin derived from β-lactoglobulin, the first natural ligand for the NTS2 receptor, showed memory-consolidating, anxiolytic-like, and hypocholesterolemic effects. Weak agonist peptides for the complements C3a and C5a receptors were released from many proteins and exerted various central effects. Peptides showing anxiolytic-like antihypertensive and anti-alopecia effects via different types of receptors such as OT, FPR and AT2 were also obtained. Based on these study, new functions and post-receptor mechanisms of receptor commom to endogenous and exogenous bioactive peptides have been clarified.