用标准蛋白质混合物建立了一种适用于低丰度混合蛋白质及其异构体分离与鉴定的蛋白质组学方法。通过IPG胶条等电聚焦分离蛋白质,染色后进行混合胶内酶切,采用纳升电喷雾毛细管液相色谱-串联质谱“散弹法(shot-gun)”分析酶切产物,并进行数据库检索鉴定蛋白质。运用该方法从K562细胞株样品中鉴定出14种具有重要功能的蛋白质,部分蛋白质同时在多个条带中出现,可能是异构体。肽段及其碎片离子的平均质量偏差小于0.05 U,综合得分大都远远超过有效值。该方法灵敏、准确度高、分辨率高、省时、便于操作,在鉴定蛋白质异构体方面有优势。 A standard proteomic mixture was used to establish a proteomic approach suitable for the isolation and characterization of low abundance mixed proteins and their isomers. Proteins were isolated by isoelectric focusing with IPG strips, mixed in gel digestion after staining, and digested products were analyzed by nanospray-capillary electrospray capillary-tandem mass spectrometry “shot-gun” and subjected to a database search Identify proteins. Using this method, 14 kinds of proteins with important functions were identified from K562 cell line samples. Some proteins appeared in multiple bands at the same time, which may be isomers. The average mass deviation of peptides and fragment ions was less than 0.05 U, and the composite scores far exceeded their effective values. The method is sensitive, accurate, high resolution, time-saving, easy to operate, and has advantages in the identification of protein isoforms.