基于NanoLC-Orbitrap技术测定六种不同栽培品种大豆中多肽Lunasin含量

大豆中含有丰富的蛋白质和多肽,其中露那辛(Lunasin)是一种重要的功能性多肽。为测定国产大豆中Lunasin的含量,本研究以六种国产大豆为实验材料,采用凝胶电泳法对国产大豆中的Lunasin成分进行分离纯化,得到含有Lunasin的凝胶条带,酶解后利用纳流液相色谱串联轨道阱质谱(Nano LC-Obitrap)平行反应监视法(PRM)分析其中的特异性肽段从而测定Lunasin的含量。测定结果表明:在六种国产大豆中,皖豆35大豆中Lunasin含量最高,为4.66 mg/g;中黄13大豆中含量为2.24 mg/g;中黄75大豆中含量为3.35 mg/g;徐豆14大豆中含量为2.59 mg/g;黔豆7号大豆中含量为2.03 mg/g;黑河43大豆中含量为2.87 mg/g。实验结果表明国产大豆中含有丰富的Lunasin。该方法前处理操作简单,重复性好、结果准确,具有较好的线性关系,此方法可用于大豆中Lunasin的含量的测定及筛选富含Lunasin的大豆品种。

Determination of Polypeptide Lunasin Content in Six Different Cultivars of Soybean Using NanoLC-Orbitrap Technique

Soybean was rich in protein and polypeptide, of which lunasin was an important functional polypeptide. In this study, the lunasin in six kinds of domestic soybeans was separated and purifiedby SDS-PAGE for the determination of lunasin content in domestic soybeans, and a gel band containing lunasin was obtained, In addition, the specific peptides were analyzed by NanoLC-Obitrap and PRM after enzymatic hydrosis, and the lunasin content was determined. The results showed that content of lunasin was 4.66 mg/g in Wangdou35 (highest content among the six kinds of domestic soybeans) , 2.24 mg/g in Zhonghuang 13, 3.35 mg/g in Zhonghuang 75, 2.59 mg/g in Xu dou14, 2.03 mg/g in Qian Dou 7, and 2.87 mg/g in Heihe 43, indicating that the domestic soybean was rich in lunasin. The proposed method in this study had the advantages of simple pretreatment, good repeatability, accurate result and good linear relationship, which could be used to determine the content of lunasin in soybean and screen the soybean varieties that were rich in lunasin.