纳升液相色谱-高分辨串联质谱研究冻存条件对唾液多肽组的影响

唾液多肽组学为疾病相关的生物标记物研究提供了新方法,但冻存条件对分析结果的影响并不清楚。本研究采用氧化石墨烯-磷酸镧纳米复合材料分离富集唾液多肽,利用纳升液相色谱-高分辨串联质谱技术,考察唾液样品分别置于-80℃与-20℃冻存6个月后对唾液多肽组的影响。结果表明,在-80℃冻存条件下的唾液样品中,共鉴定出归属于33种蛋白的429条肽段；在-20℃冻存条件下的唾液样品中,鉴定出595条肽段,对应31种蛋白。实验结果表明,相比于-80℃,唾液置于-20℃条件下的新增加肽段主要来源于已有肽段的降解,并且唾液中的蛋白质也发生了一定降解。本研究在肽段序列水平上考察了冻存条件对多肽的影响,结果表明,-20℃冻存条件不适合长期保存用于多肽组分析的唾液样品。本研究结果可为相关医学研究提供借鉴。

Study of Frozen Storage Conditions Impacting on Salivary Peptidomic by High Resolution Tandem Mass Spectrometry

The salivary peptidomics provides a new method for study of disease biomarkers, but the effect of frozen storage conditions on analysis results is not very clear. In this study, we separated and enriched these peptides in human saliva by graphene-lanthanide phosphate composite nanomaterial ( LaGM) , then identified them by nano-liquid chromatography-high resolution tandem mass spectrometry. The salivary samples were analyzed after these samples were stored at -20℃ and -80℃ for six months respectively. We identified 429 peptides which belong to 33 proteins at -80℃ and 595 peptides corresponding to 31 proteins at -20℃. In comparison with the sample stored at -80℃, the "new" saliva peptides were mainly from the degradation of existing peptides. In addition, some salivary proteins also had a degree of degradation after stored at -20℃. In peptide sequence level, this study illustrated that frozen storage conditions had effects on salivary peptidome, suggesting that saliva sample should not be stored at -20℃ for long time when used to analyze peptidomics. This method can provide reference for relevant medical research.