Design,preparation and application of chuitosan derivatives materials for specific enriching thiol oligopeptides base on pH-responsive

• 1、Biotechnology School,Jiangnan University,Wuxi 214122

Abstract：How to realize the non-destructive adsorption / desorption of thiol oligopeptides has always been a difficult problem in the field of thiol oligopeptide analysis. To solve this problem, chitosan (CTS) was used as the raw material, the phenylboric acid group was introduced at the position of chitosan C2, through the reaction of 3-formylphenylboric acid with the amino group on chitosan, and carboxymethyl was introduced at the position of chitosan C6 by chloroacetic acid under alkaline condition, so as to O-carboxymethyl chitosan-formylphenylboric acid (O-CMC-PBS) with pH responsive ability was prepared. It was dissolved at pH≥6.0, self-assembly becomes turbid and centrifuges to form precipitates at pH≤4.5, and precipitates was dissolved at pH≥10.0. Then, the 5-methylenepyrrolidone (5MP) had the characteristics of covalently bind thiol oligopeptides at pH 6.0-8.5 and release bound thiol oligopeptides at pH ≥9.5. Therefore, the chitosan derivative O-CMC-PBS-5MP with pH responsive self-assembly / disassembly and thiol oligopeptides adsorption/desorption functions was prepared by introducing 5MP group into the amino group of O-CMC-PBS, which can be covalently bonded to thiol oligopeptide at pH 6.0-8.0, and released at pH≥10.0; At pH 6.0-8.0, O-CMC-PBS-5MP dissolves in water and could specifically react with mercapto on oligopeptide to realize the function of binding thiol oligopeptides, the adsorption rate is up to 64% in 2 hours, and the maximum adsorption rate can reach 95%; At pH≤3.0, the material that adsorbs thiol oligopeptide is condensed due to self-assembly, and the thiol oligopeptide can be enriched by centrifugation; Then, the precipitate is dissolved in a small amount of distilled water to adjust the pH ≥10.0 by adding ammonia, the precipitate reconstituted thiol The oligopeptide is released into the solution, Adjust pH≤3.0 with formic acid again to realize the self-assembly precipitation of O-CMC-PBS-5MP and the enrichment of high-purity thiol oligopeptides in the supernatant, with a total recovery rate of 50%.The thiol oligopeptides enrichment / concentration material developed in this study, O-CMC-PBS-5MP, achieved the first non-destructive enrichment and concentration of thiol oligopeptides, which laid the foundation for mass spectrometry analysis of thiol oligopeptides.

Keywords： high polymer material chitosan 5-methylene pyrrolones thiol oligopeptides pH response non-destructive specific enrichment