title: Characterization of Tyr-Leu-Gly, a novel anxiolytic-like peptide released from bovine αS-casein.
abstract: We found previously that dipeptide YL exhibits orally active anxiolytic activity comparable to diazepam. The YL sequence is often observed in the primary structure of natural food proteins. In the present study, we investigated whether YL and YL analogues are released from bovine αS-casein by gastrointestinal proteases. YLG, corresponding to αS1-casein (aa 91-93), was more effectively released from αS-casein than YL by pepsin-pancreatin digestion, mimicking gastrointestinal enzymatic conditions. Using the synthetic model peptide, we determined that trypsin cleaved the N terminus of YLG, and elastase and carboxypeptidase contributed to cleave the C-terminus. YLG exhibited orally active anxiolytic-like activity in the elevated plus maze and open-field tests in mice. The anxiolytic-like activity of YLG was inhibited by WAY100135, SCH23390 or bicuculline, antagonists of serotonin 5-HT1A, dopamine D1, and GABA(A) receptors, respectively; however, YLG had no affinity for these receptors. The pepsin-pancreatin digest of αS-Casein also exhibited anxiolytic-like activity. Meanwhile, anxiolytic-like activity of α-casozepine, an αS1-casein-derived decapeptide with YL sequence in the N terminus, was blocked by WAY100135, SCH23390, or bicuculline, equally to YLG and YL; however, it was not detected in the pepsin-pancreatic digest. Taken together, we found that YLG is released after pepsin-pancreatic digestion of αS-casein and exhibits potent anxiolytic-like activity via activation of serotonin, dopamine, and the GABA receptor system.
authors.affiliation: Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Gokasho Uji, Kyoto 611-0011, Japan.
authors.forename: Takafumi
authors.initials: T
authors.lastname: Mizushige
authors.forename: Yurina
authors.initials: Y
authors.lastname: Sawashi
authors.forename: Ayako
authors.initials: A
authors.lastname: Yamada
authors.forename: Ryuhei
authors.initials: R
authors.lastname: Kanamoto
authors.forename: Kousaku
authors.initials: K
authors.lastname: Ohinata
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D014151:Anti-Anxiety Agents / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D001552:Benzazepines / Q000494:pharmacology; D001640:Bicuculline / Q000494:pharmacology; D002268:Carboxypeptidases / Q000378:metabolism; D002364:Caseins / Q000737:chemistry / Q000378:metabolism*; D002417:Cattle; D004305:Dose-Response Relationship, Drug; D041981:Gastrointestinal Tract / Q000201:enzymology; D008297:Male; D018782:Maze Learning / Q000187:drug effects; D051379:Mice; D008969:Molecular Sequence Data; D009043:Motor Activity / Q000187:drug effects; D009842:Oligopeptides / Q000737:chemistry / Q000378:metabolism*; D010196:Pancreatic Elastase / Q000378:metabolism; D010194:Pancreatin / Q000378:metabolism; D010434:Pepsin A / Q000378:metabolism; D010447:Peptide Hydrolases / Q000378:metabolism*; D010879:Piperazines / Q000494:pharmacology; D044282:Receptor, Serotonin, 5-HT1A / Q000378:metabolism; D017447:Receptors, Dopamine D1 / Q000378:metabolism; D011963:Receptors, GABA-A / Q000378:metabolism; D014357:Trypsin / Q000378:metabolism
chemical_list: D014151:Anti-Anxiety Agents; D001552:Benzazepines; D002364:Caseins; D009842:Oligopeptides; D010879:Piperazines; D017447:Receptors, Dopamine D1; D011963:Receptors, GABA-A; C534628:SCH 23390; D044282:Receptor, Serotonin, 5-HT1A; C081293:WAY 100135; D010194:Pancreatin; D002268:Carboxypeptidases; D010447:Peptide Hydrolases; D010196:Pancreatic Elastase; D014357:Trypsin; D010434:Pepsin A; D001640:Bicuculline
keywords: gastrointestinal protease; neurotransmitter; tripeptide