2709碱性蛋白酶水解BSA蛋白肽谱变化的研究

以2709碱性蛋白酶酶解牛血清白蛋白为研究对象,采用液相色谱-飞行时间质谱联用分析方法和位点非特异性酶切肽谱鉴定方法,分析水解过程中肽谱的动态变化。蛋白电泳分析结果显示,2709碱性蛋白酶在0.1%的添加比例条件下,0.5 h内可将全部蛋白降解,表明其具有极强的水解能力。肽谱分析结果显示,该酶酶解BSA蛋白过程中肽谱变化复杂多样,不同序列多肽具有不同的动态变化特征。酶切位点分析结果显示,2709碱性蛋白酶几乎能在所有种类的氨基酸位点发生酶切,但酶切的频率并不相同,这表明该酶在水解位点上具有宽泛的选择性和一定的倾向性,其中在肽键C端氨基酸种类的选择上具有明显的亮氨酸倾向性。该文可为研究其他工业蛋白酶水解肽谱的规律提供借鉴,并有助于提高我国工业蛋白酶制剂的应用水平和蛋白质加工水平。

Study on Peptide Mapping Changes of BSA Protein Hydrolyzed by 2709 Alkaline Proteinase

In this paper,the peptide hydrolysates from bovine serum albumin(BSA)hydrolyzed by 2709 alkaline proteinase were analyzed by liquid chromatography coupled with quadrupole time-of-flight mass spectrometry,and then identified by the site-unspecified identification method of peptide mapping.The protein electrophoresis analysis indicated that all of BSA proteins were hydrolyzed by 2709 alkaline proteinase added at 0.1% level in 0.5 h,suggesting a strong proteolysis ability.The results of peptide mapping analysis indicated that the changes of peptide mapping were complex during the proteolysis process and different peptides displayed variable change features.The analysis of cleavage sites indicated that 2709 alkaline proteinase could be cleaved at almost any kind of amino acid sites,but their cleavage frequency were different.It suggested that besides broad site selectivity,2709 alkaline proteinase had a certain tendency of site selection in the proteolysis of BSA,with a significant selectivity tendency on leucine sites.The study provided a theoretic foundation for the rational use of 2709 alkaline proteinase in hydrolyzing proteins,and will help to improve the application of proteases in food industry in future.