title: Soy-ghretropin, a novel ghrelin-releasing peptide derived from soy protein.
abstract: We investigated exogenous secretagogues of ghrelin, which is an orexigenic hormone isolated from the stomach. We found that the tryptic digest of soy β-conglycinin stimulated ghrelin secretion by the ghrelin-producing cell line, MGN3-1. We then identified a 22-amino acid peptide corresponding to the β-conglycinin α-subunit(192-213) [βCGα(192-213)] from an active fraction separated by HPLC. The N-terminal undecapeptide of βCGα(192-213), NKNPFLFGSNR, exhibited ghrelin-releasing activity at a lower dose than that of βCGα(192-213). We named NKNPFLFGSNR 'soy-ghretropin', which corresponds to βCGα(192-202). Neither [des-N(1) K(2) ]-soy-ghretropin nor [des-R(11) ]-soy-ghretropin stimulated ghrelin secretion; hence, both the N- and C-terminal structures of soy-ghretropin were indispensable. Orally administered soy-ghretropin increased plasma ghrelin levels and food intake in vivo. Soy-ghretropin is the first exogenous ghrelin-releasing peptide derived from food protein.
authors.affiliation: Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Japan.
authors.forename: Junya
authors.initials: J
authors.lastname: Nakato
authors.affiliation: Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Japan.
authors.forename: Hayato
authors.initials: H
authors.lastname: Aoki
authors.affiliation: Medical Innovation Center, Kyoto University Graduate School of Medicine, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Iwakura
authors.affiliation: Kazusa DNA Research Institutes, Kisarazu, Chiba, Japan.
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Suzuki
authors.affiliation: Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Japan.
authors.forename: Ryuhei
authors.initials: R
authors.lastname: Kanamoto
authors.affiliation: Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Japan.
authors.forename: Kousaku
authors.initials: K
authors.lastname: Ohinata
mesh_terms: D052179:Antigens, Plant / Q000737:chemistry / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D004435:Eating; D054439:Ghrelin / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D005916:Globulins / Q000737:chemistry / Q000378:metabolism; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism*; D054440:Receptors, Ghrelin / Q000235:genetics / Q000378:metabolism*; D055314:Seed Storage Proteins / Q000737:chemistry / Q000378:metabolism*; D030262:Soybean Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D052179:Antigens, Plant; D054439:Ghrelin; D005916:Globulins; D010446:Peptide Fragments; D054440:Receptors, Ghrelin; D055314:Seed Storage Proteins; D030262:Soybean Proteins; C100565:alpha-conglycinin, Glycine max; C013894:beta-conglycinin protein, Glycine max; C000618325:soy-ghretropin protein, Glycine max
keywords: food protein; ghrelin; peptide; structure-activity relationship