电喷雾-串联四极杆-飞行时间质谱法分析寡肽的一级结构

Studies on Primary Structures of Oligopeptides by Electrospray Ionization-Quadrupole Time-of-flight Mass Spectrometry

报道了 3种人工合成寡肽的电喷雾 串联四极杆 飞行时间 (ESI QqTOF)质谱的鉴定方法。采用TOFMS模式分别测定了 3种样品的分子量。再利用子离子模式 (ProductIon)对 [M +H]+ 或 [M +2H]2 + 进行CID分析 ,根据肽类分子的质谱碎裂规律推断寡肽的一级结构。结果表明 :ESI QqTOF质谱能测定出寡肽母离子与子离子的精确分子量 ,质量准确度小于 2 0× 10 - 6 ,能直接区分赖氨酸与谷氨酰氨残基 (Δm =0 .0 36Da) ,可为蛋白质的鉴定提供更准确的氨基酸序列信息 ,是蛋白质组学研究的理想工具。

This study reports a procedure developed for the identification of oligopeptides using electrospray ionization-quadrupole time-of-flight mass spectrometry (ESI-QqTOF MS). Firstly, the molecular weight of three synthesized peptides was determined in TOF MS mode. Then their sequences were interpreted from b-ions by the collision-induced dissociation (CID) using the single or doubly charged peptides in the product ion mode. The data suggested the accurate precursor and product ion mass information ( < 20 x 10(-6)) could unambiguously identify primary amino acid sequences differing by lysine vs glutamine (&UDelta;m = 0.036 Da). By virtue of its high resolution, capability for accurate mass measurements, and high sensitivity, the instrument is ideally suited to protein identification for proteomic applications by generation of. peptide tags, manual sequence interpretation.