Wang Sheng, Xiao Zhaohui, Xiao Chunsheng, Wang Huixin, Wang Bing, Li Ying, Chen Xuesi, Guo Xinhua
College of Chemistry, Jilin University, Changchun, 130012, China.
Key Laboratory of Polymer Ecomaterials, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022, China.
J Am Soc Mass Spectrom. 2016 Apr;27(4):709-18. doi: 10.1007/s13361-015-1325-5. Epub 2016 Jan 4.
Low-abundance samples and salt interference are always of great challenges for the practical protein profiling by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). Herein, a series of carboxyl-esterified derivatives of α-cyano-4-hydroxycinnamic acid (CHCA) were synthesized and evaluated as matrices for MALDI-MS analysis of protein. Among them, (E)-propyl α-cyano-4-hydroxyl cinnamylate (CHCA-C3) was found to exhibit excellent assay performance for intact proteins by improving the detection sensitivity 10 folds compared with the traditional matrices [i.e., super2,5-dihydroxybenzoic acid (superDHB), sinapic acid (SA), and CHCA]. In addition, CHCA-C3 was shown to have high tolerance to salts, the ion signal of myoglobin was readily detected even in the presence of urea (8 M), NH4HCO3 (2 M), and KH2PO4 (500 mM), meanwhile sample washability was robust. These achievements were mainly attributed to improved ablation ability and increased hydrophobicity or affinity of CHCA-C3 to proteins in comparison with hydrophilic matrixes, leading to more efficient ionization of analyte. Furthermore, direct analysis of proteins from crude egg white demonstrated that CHCA-C3 was a highly efficient matrix for the analysis of low-abundance proteins in complex biological samples. These outstanding performances indicate the tremendous potential use of CHCA-C3 in protein profiling by MALDI-MS. Graphical Abstract ᅟ.
对于通过基质辅助激光解吸/电离质谱（MALDI-MS）进行实际蛋白质分析而言，低丰度样品和盐干扰一直是巨大的挑战。在此，合成了一系列α-氰基-4-羟基肉桂酸（CHCA）的羧基酯化衍生物，并评估其作为蛋白质MALDI-MS分析的基质。其中，发现（E）-α-氰基-4-羟基肉桂酸丙酯（CHCA-C3）对完整蛋白质表现出优异的分析性能，与传统基质[即超2,5-二羟基苯甲酸（superDHB）、芥子酸（SA）和CHCA]相比，检测灵敏度提高了10倍。此外，CHCA-C3对盐具有高耐受性，即使在存在尿素（8 M）、碳酸氢铵（2 M）和磷酸二氢钾（500 mM）的情况下，肌红蛋白的离子信号也能很容易地检测到，同时样品的可清洗性很强。这些成果主要归因于与亲水性基质相比，CHCA-C3的烧蚀能力提高以及对蛋白质的疏水性或亲和力增加，从而导致分析物更有效地电离。此外，对粗蛋清中的蛋白质进行直接分析表明，CHCA-C3是用于分析复杂生物样品中低丰度蛋白质的高效基质。这些出色的性能表明CHCA-C3在通过MALDI-MS进行蛋白质分析方面具有巨大的潜在用途。图形摘要ᅟ。
