title: Isolation and identification of indigestible pyroglutamyl peptides in an enzymatic hydrolysate of wheat gluten prepared on an industrial scale.
abstract: An enzymatic hydrolysate of wheat gluten was further digested in vitro with porcine pepsin and pancreatin to obtain an indigestible peptide. Indigestible pyroglutamyl peptide was isolated from the digest by strong cation-exchange, size-exclusion, and reversed-phase chromatographies. The pyroglutamyl peptide was digested with pyroglutamate aminopeptidase, and the digest was reacted with phenyl isothiocyanate. The resultant phenylthiocarbamyl (PTC) peptides were purified by reversed-phase HPLC by using binary gradient elution with ammonium acetate buffer, pH 6.0, and acetonitrile. The PTC peptides were analyzed with an automatic peptide sequencer on the basis of the Edman degradation method with a modified program. Some pyroglutamyl peptides were also analyzed by fast-atom bombardment ionization mass spectrometry without the pyroglutamate amino peptidase digestion. Consequently, pyroGlu-Asn-Pro-Gln, pyroGlu-Gln-Gln-Pro-Gln, pyroGlu-Gln-Pro-Gln, pyroGlu-Gln-Pro-Gly-Gln-Gly-Gln, pyroGlu-Gln, pyroGlu-Gln-Pro, pyroGlu-Ile-Pro-Gln, pyroGlu-Ile-Pro, pyroGlu-Gln-Pro-Leu, pyroGlu-Gln-Phe-Pro-Gln, pyroGlu-Ser-Phe-Pro-Gln, pyroGlu-Phe-Pro-Gln, and pyroGlu-Gln-Pro-Pro-Phe-Ser were identified.
authors.affiliation: Department of Food Sciences & Nutritional Health, Kyoto Prefectural University, Shimogamo, Japan.
authors.forename: Noriko
authors.initials: N
authors.lastname: Higaki-Sato
authors.forename: Kenji
authors.initials: K
authors.lastname: Sato
authors.forename: Yasuaki
authors.initials: Y
authors.lastname: Esumi
authors.forename: Takeshi
authors.initials: T
authors.lastname: Okumura
authors.forename: Hideki
authors.initials: H
authors.lastname: Yoshikawa
authors.forename: Chie
authors.initials: C
authors.lastname: Tanaka-Kuwajima
authors.forename: Akie
authors.initials: A
authors.lastname: Kurata
authors.forename: Makoto
authors.initials: M
authors.lastname: Kotaru
authors.forename: Makoto
authors.initials: M
authors.lastname: Kawabata
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Nakamura
authors.forename: Kozo
authors.initials: K
authors.lastname: Ohtsuki
mesh_terms: D000595:Amino Acid Sequence; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D005983:Glutens / Q000737:chemistry* / Q000378:metabolism; D006868:Hydrolysis; D010194:Pancreatin / Q000378:metabolism; D010434:Pepsin A / Q000378:metabolism; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism; D010455:Peptides / Q000032:analysis* / Q000302:isolation & purification / Q000378:metabolism; D011751:Pyroglutamyl-Peptidase I / Q000378:metabolism; D011761:Pyrrolidonecarboxylic Acid / Q000032:analysis* / Q000378:metabolism; D020539:Sequence Analysis, Protein; D016339:Spectrometry, Mass, Fast Atom Bombardment; D014908:Triticum / Q000737:chemistry*
chemical_list: D010446:Peptide Fragments; D010455:Peptides; D005983:Glutens; D010194:Pancreatin; D011751:Pyroglutamyl-Peptidase I; D010434:Pepsin A; D011761:Pyrrolidonecarboxylic Acid