title: Isolation and structure characterization of an antioxidative glycopeptide from mycelial culture broth of a medicinal fungus.
abstract: A novel glycopeptide (Cs-GP1) with an average molecular weight (Mw) of 6.0 kDa was isolated and purified by column chromatography from the lower Mw fraction of exopolysaccharide (EPS) produced by a medicinal fungus Cordyceps sinensis Cs-HK1. Its carbohydrate moiety was mainly composed of glucose and mannose at 3.2:1.0 mole ratio, indicating an O-linked glycopeptide. The peptide chain contained relatively high mole ratios of aspartic acid, glutamic acid and glycine (3.3-3.5 relative to arginine) but relatively low ratios of tyrosine and histidine. The peptide chain sequence analyzed after trypsin digestion by LC-MS was KNGIFQFGEDCAAGSISHELGGFREFREFLKQAGLE. Cs-GP1 exhibited remarkable antioxidant capacity with a Trolox equivalent antioxidant capacity of 1183.8 μmol/g and a ferric reducing ability of 611.1 μmol Fe(II)/g, and significant protective effect against H2O2-induced PC12 cell injury at a minimum dose of 10 μg/mL. This is the first report on the structure and bioactivity of an extracellular glycopeptide from the Cordyceps species.
authors.affiliation: Department of Applied Biology & Chemical Technology, State Key Laboratory of Chinese Medicine and Molecular Pharmacology in Shenzhen, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong. jian-yong.wu@polyu.edu.hk.
authors.forename: Jian-Yong
authors.initials: JY
authors.lastname: Wu
authors.affiliation: Department of Applied Biology & Chemical Technology, State Key Laboratory of Chinese Medicine and Molecular Pharmacology in Shenzhen, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong. xiachentiger@gmail.com.
authors.forename: Xia
authors.initials: X
authors.lastname: Chen
authors.affiliation: Department of Applied Biology & Chemical Technology, State Key Laboratory of Chinese Medicine and Molecular Pharmacology in Shenzhen, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong. chai_chai_1987@hotmail.com.
authors.forename: Ka-Chai
authors.initials: KC
authors.lastname: Siu
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000975:Antioxidants / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D002470:Cell Survival / Q000187:drug effects; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D032661:Cordyceps / Q000378:metabolism*; D006020:Glycopeptides / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D006861:Hydrogen Peroxide / Q000633:toxicity; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009005:Monosaccharides / Q000032:analysis; D016716:PC12 Cells; D051381:Rats; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D000975:Antioxidants; D006020:Glycopeptides; D009005:Monosaccharides; D006861:Hydrogen Peroxide