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分析和比较疾病组及健康对照组的混合样品是血清多肽组生物标记物研究的常用方法,但对健康个体多肽组的差异和共性关注较少。本研究利用纳升液相色谱-高分辨四级杆飞行时间质谱鉴定健康人混合血清样品(20例)的多肽组,阐明血清多肽组的分子量分布等一般特征,进而选取6例个体样品单独分析并与混合样品的分析结果进行比较,说明正常健康样品之间的个体差异和共同成分。结果表明,可鉴定序列的血清多肽组的分子量范围在7000 Da以下,纤维蛋白原α链等蛋白质所属肽段的检出频率最高,肽段在蛋白质水平上分布具有不均一性,排在前10%的蛋白质占据了约50%的总肽段,而后40%的蛋白质只有1条检出肽段。此外,在所有样品中都检测到了来自于8个蛋白质的12个共同肽段,检测到了N端乙酰化、氨基酸氧化、磷酸化、脱氨化和脱水等翻译后修饰和明显的阶梯序列现象。本研究在肽段序列水平分析了血清多肽组的基本特征和个体差异,可为血清多肽组生物标志物研究提供参考。
Analysis and comparison of pooled samples from disease and healthy control groups are common methods for the study of serum polypeptide biomarkers, but less attention has been paid to the differences and commonalities among healthy individuals. In this study, we used nanoliter liquid chromatography-high-resolution quadrupole time-of-flight mass spectrometry to identify the polypeptide group of healthy human mixed serum samples (20 cases), clarified the general characteristics of the serum polypeptide group molecular weight distribution, and then selected six individual samples And compared with the results of analysis of mixed samples to illustrate the individual differences and common components between normal healthy samples. The results showed that the molecular weight range of the identifiable sequence was less than 7000 Da. The detection frequency of the peptides belonging to the α chain of fibrinogen was the highest, and the distribution of peptides was heterogeneous at the protein level About 50% of the total protein is occupied by the protein, and only one of the 40% of the protein is detected. In addition, 12 common peptides from 8 proteins were detected in all samples, and post-translational modifications such as N-terminal acetylation, amino acid oxidation, phosphorylation, deamination and dehydration, and obvious ladder-like phenomena were detected. In this study, we analyzed the basic characteristics and individual differences of serum polypeptide group at the peptide sequence level, which could provide a reference for the study of serum polypeptide biomarkers.