title: Antioxidant peptide isolated from muscle protein of bullfrog, Rana catesbeiana Shaw.
abstract: Bullfrog (Rana catesbeiana Shaw) muscle protein was enzymatically hydrolyzed for extraction of an antioxidant peptide. Antioxidant peptide from bullfrog muscle protein hydrolysate (APBMH) was purified using consecutive chromatographic methods, and the amino acid sequence was identified as being Leu-Glu-Gln-Gln-Val-Asp-Asp-Leu-Glu-Gly-Ser-Leu-Glu-Gln-Glu-Lys-Lys (molecular mass of 1,988 Da) by quantitative time-of-flight electrospray ionization mass spectroscopy. To assess antioxidant activities of APBMH, two different in vitro systems were employed: free radical scavenging activity by electron spin resonance (ESR) spectroscopy and polyunsaturated fatty acid (PUFA) peroxidation inhibition assay. ESR revealed that APBMH is an effective free radial scavenger with activity similar to that of vitamin C against 1,1-diphenyl-2-picrylhydrazyl, hydroxyl, and superoxide radicals, and its 50% inhibitory concentration values were 179.4 microM, 162.7 microM, and 176.1 microM, respectively. APBMH also significantly retarded PUFA oxidation, and more potently than did alpha-tocopherol, which was used as a positive control. In addition, the ability of APBMH to inhibit the oxidative damage of DNA was assessed, in vitro, by measuring the conversion of supercoiled pBR322 plasmid DNA to the open circular form. It was found that APBMH significantly protected hydroxyl radical-induced DNA damage dose-dependently.
authors: Division of Food Science and Aqualife Medicine, Chonnam National University, Yeosu, Republic of Korea.
authors: Jae-Young
authors: JY
authors: Je
authors: Zhong-Ji
authors: ZJ
authors: Qian
authors: Se-Kwon
authors: SK
authors: Kim
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000975:Antioxidants / Q000302:isolation & purification* / Q000494:pharmacology; D002851:Chromatography, High Pressure Liquid; D004249:DNA Damage / Q000187:drug effects; D004578:Electron Spin Resonance Spectroscopy; D006868:Hydrolysis; D017665:Hydroxyl Radical / Q000494:pharmacology; D015227:Lipid Peroxidation / Q000187:drug effects; D009124:Muscle Proteins / Q000737:chemistry*; D010447:Peptide Hydrolases / Q000378:metabolism; D010455:Peptides / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D011892:Rana catesbeiana; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D000975:Antioxidants; D009124:Muscle Proteins; D010455:Peptides; D017665:Hydroxyl Radical; D010447:Peptide Hydrolases