Isolation and characterization of a group of oligopeptides related to oxidized glutathione from the root of Panax ginseng.
Six gamma-glutamyl oligopeptides were isolated for the first time from aqueous methanol extracts of Panax ginseng root by using column chromatography on ion-exchange resin, gel filtration and reverse-phase high-performance liquid chromatography. Their structures had been established with the methods of amino acid analysis, N-terminal, C-terminal determination and double-coupling sequence analysis. They were: P-I (N-gamma-glutamylcystinyl-bis-glycine), P-ll (gamma-glutamylcysteinylglycine disulfide, oxidized glutathione), P-III (N,N'-bis-gamma-glutamylcystinylglycine), P-IV (gamma-glutamylcysteinylglycinamide disulfide), P-V (N-gamma-glutamylglycylcysteine disulfide), P-VI(gammaglutamylarginine); five of them are related to oxidized glutathione. The structures were further confirmed by the chemical synthesis. As far as we know, P-V (N-gamma-glutamylglycylcysteine disulfide) is a new biologically active peptide which exhibits somnogenic effect and is more potent than that of P-II.
Chen
Z K
ZK
Department of Chemistry, Peking University, Beijing, China.
Fan
C X
CX
Ye
Y H
YH
Yang
L
L
Jiang
Q
Q
Xing
Q Y
QY
D000596:Amino Acids / Q000032:analysis; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D005978:Glutathione / Q000378:metabolism*; D010084:Oxidation-Reduction; D005894:Panax / Q000737:chemistry*; D010455:Peptides / Q000737:chemistry* / Q000302:isolation & purification* / Q000378:metabolism; D010940:Plant Proteins / Q000302:isolation & purification / Q000378:metabolism; D018517:Plant Roots / Q000737:chemistry; D010946:Plants, Medicinal; D011487:Protein Conformation
D000596:Amino Acids; D010455:Peptides; D010940:Plant Proteins; D005978:Glutathione