Isolation and identification of indigestible pyroglutamyl peptides in an enzymatic hydrolysate of wheat gluten prepared on an industrial scale.
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.
Higaki-Sato
Noriko
N
Department of Food Sciences & Nutritional Health, Kyoto Prefectural University, Shimogamo, Japan.
Sato
Kenji
K
Esumi
Yasuaki
Y
Okumura
Takeshi
T
Yoshikawa
Hideki
H
Tanaka-Kuwajima
Chie
C
Kurata
Akie
A
Kotaru
Makoto
M
Kawabata
Makoto
M
Nakamura
Yasushi
Y
Ohtsuki
Kozo
K
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*
D010446:Peptide Fragments; D010455:Peptides; D005983:Glutens; D010194:Pancreatin; D011751:Pyroglutamyl-Peptidase I; D010434:Pepsin A; D011761:Pyrrolidonecarboxylic Acid