体外模拟消化芝麻蛋白产生抗氧化肽的分离纯化与构效研究

为研究芝麻蛋白在胃肠道中产生抗氧化肽的结构与构效关系,本试验采用体外模拟消化水解芝麻蛋白,通过超滤水解液,制备液相分离,利用液质联用仪进行结构鉴定,合成相应多肽以验证活性,并对抗氧化活性最高的多肽开展构效关系研究和安全性预测。结果表明,芝麻蛋白经分离纯化与结构鉴定,共获得19条芝麻抗氧化肽,其中17条来自芝麻贮藏蛋白,2条来自芝麻非贮藏蛋白。源自非贮藏蛋白的HLFLSGVACFG具有最强的抗氧化活性,其活性中心可能位于His1,Phe3,Cys9。缩小Cys9羧基端取代基团,增大Leu2区域的取代基,增强N端带正电取代基和C端带负电取代基,有利于提高HLFLSGVACFG的抗氧化活性。经预测,该多肽无毒性与致敏性。上述结果表明,作为蛋白主体的芝麻贮藏蛋白生成抗氧化肽的同时,低含量的芝麻非贮藏蛋白因能产生高活性的抗氧化肽,也是重要的抗氧化肽前体。活性和安全性较高的HLFLSGVACFG具有研究利用价值。本研究初步揭示了芝麻蛋白在人体内产生抗氧化肽的规律、抗氧化肽组成及构效关系,深化了芝麻抗氧化肽的研究,为抗氧化肽结构修饰研究提供了理论参考。

Separation,Purification, Structure-Activity Relationship of Antioxidant Peptides Derived From in vitro Gastrointestinal Digestion of Sesame Protein

To research the structure and structure-activity relationship of sesame antioxidant peptides generated in the gastrointestinal tract, in vitro gastrointestinal digestion was used to hydrolyze sesame protein, and then the hydrolysate was separated by ultrafiltration, preparative high performance liquid chromatography successively. Structures of peptides were identified by liquid chromatography- mass spectrometry, and these peptides were synthetized to testify antioxidant activity. The structure-activity relationship and safety prediction of the strongest antioxidant peptide were investigated. The results showed that 19 antioxidant peptides of sesame were found via separation, purification and structure identification. Amang them 17 peptides originated from sesame storage protein, and the rest was originated from non-storage protein. HLFLSGVACFG derived from non-storage protein showed the highest antioxidant activity, in which the active site tended to locate on His1, Phe3 and Cys9. shrinking the substituent group on the carboxy-terminal of Cys9, expanding the substituent group on the Leu2, strengthen the positive charged group on the N-terminal and the negative charged group on the C-terminal were in favor of the antioxidant activity of HLFLSGVACFG. According to the safety prediction, this peptide was non-toxic and non-allergen. The above results illuminated that excepted from storage protein as main body, sesame protein enabled to generate antioxidant peptide, minor non-storage protein was also an important precursor of antioxidant peptide due to produce high antioxidant activity peptide. High activity and safe HLFLSGVACFG has research and application value. This research preliminarily revealed the rule that sesame protein generates antioxidant peptides in vivo, the composition and structure-activity relationship of antioxidant peptide, which deepens the research on sesame antioxidant peptide and provides the theoretical reference for the structural modification of antioxidant peptides.