| Summary: | 碩士 === 國立中興大學 === 分子生物學研究所 === 103 === The cyclic peptide is one kind of cyclic compounds which combine of the protein and non-protein amino acids, and the carboxyl function at the C-terminus of a peptide forms a peptide bond with the N-terminal amine group a cyclic peptide is formed. A wide variety of cyclic peptides, and all has different biological functions, such as antibodies, anti-bacterial, anti-cancer, anti-immune substances, toxic substances, ion transfer regulators or protein binding inhibitor. The application of the cyclic peptide is quite diverse, for example: animal feed additive, biopesticide, surfactants, cosmetic or human drug. In the past few years, because the overuse of antibiotics, the cyclic peptides from microorganism are gradually attracted the attention of scholars. The research strategy of this experiment is based on mass analysis, using liquid chromatography tandem mass spectrometry (LC-MS/MS) combine with selected reaction monitoring (SRM) to quantitative of five cyclic peptides antibiotics (polymyxin b, colistin a, colistin b, surfactin, iturin a) in a variety of matrices (bacterial, liver and milk), and combine with electron-transfer coupled with collision-induced dissociation (ET/CID) to sequence cyclic peptides, trying to join with metal chloride solution by sheath liquid, that expect to enhance the number of electric charge for cyclic peptides in the electrospray ionization method, and observe whether increases the sequence coverage of ETD, to establishment of a cyclic peptide containing such compounds ET/CID and SRM analysis platform.
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