三氟乙酸及甲酸体系下重组人促红素液质肽图的比较

Comparison of peptide mass map of recombinant human erythropoietin in trifluoroacetic acid and formic acid systems

目的探讨流动相中添加三氟乙酸(trifluoroacetic acid,TFA)或甲酸(formic acid,FA)时,重组人促红素(erythropoietin,EPO)液质肽图中各肽段的保留时间、峰面积及离子化效率的差异。方法将重组人EPO样品进行酶切,分别在含0.1%TFA及0.1%FA的流动相体系下测定液质肽图。通过分析质谱数据对各色谱峰进行定性,记录并计算各肽段的保留时间、峰面积及质谱信号强度。结果两种添加剂体系下,各肽段的保留时间存在差异,大部分肽段的保留时间变化在1 min左右,个别肽段超过2 min;TFA体系下各肽段的峰面积相对较小,约为FA体系下的84%;FA体系下各肽段离子化效率较高,信号强度一般为TFA体系的6倍,个别肽段高达10倍以上。结论两种体系下重组人EPO的液质肽图存在较大差异,应根据实验目的选择合适的流动相添加物。

Objective To investigate the differences in retention time, peak area and ionization efficiency of peptides in peptide mass map of recombinant human erythropoietin（EPO） in trifluoroacetic acid（TFA） and formic acid（FA）systems. Methods Recombinant human EPO was digested with enzyme, of which the peptide mass map was analyzed with mobile phase containing 0. 1% TFA or 0. 1% FA. The peaks were identified by mass spectrometry, while the retention time, peak area and ion response of each peptide were recorded and calculated. Results The retention time of peptides varied according to the addictives of mobile phase, and the differences were mainly less than 1 min with very few peptides over 2 min. The peak area of peptides in TFA system was about 84% of that in FA system. The ion efficiency of peptides in FA system was 6 times, with some peptides more than 10 times higher, than that in TA system. Conclusion There are obvious distinctions between peptide mass maps obtained with two addictives which should be chosen depending on particular purpose.