Wang Yuebo, Chen Wei, Wu Jianshuang, Guo Yinlong, Xia Xinghua
Key Laboratory of Analytical Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, China.
J Am Soc Mass Spectrom. 2007 Aug;18(8):1387-95. doi: 10.1016/j.jasms.2007.04.014. Epub 2007 Apr 29.
Because of its good biocompatibility, high surface-to-volume ratio, and distinct surface electrical properties, porous anodic alumina (PAA) membrane has been used to selectively enrich phosphopeptides from a mixture of synthetic peptides and tryptic digest product of beta-casein by a direct MALDI-TOF MS analysis. As we reported previously, PAA membrane has strong incorporation ability to the phosphate anion. Herein, we describe the application of PAA membrane as a selective sampling absorbent for phosphopeptides. The PAA membrane could enrich phosphopeptides with high efficiency and selectivity; for example, the tryptic digest product of beta-casein at a concentration as low as 4 x 10(-9) M can be satisfactorily detected. Compared to that from the nonenriching peptide mixture, the MS signal of the phosphorylated peptides enriched by the PAA membrane is remarkably improved. In addition, acidic peptides have insignificant influence on the enriching process. Results show that the adsorption of phosphate anions on the PAA membrane plays a determining role in achieving highly selective enriching capacity toward phosphopeptides. The feasibility of PAA membranes as specific absorbents for phosphopeptides is also demonstrated.
由于具有良好的生物相容性、高的比表面积和独特的表面电学性质，多孔阳极氧化铝（PAA）膜已被用于通过直接基质辅助激光解吸电离飞行时间质谱（MALDI-TOF MS）分析，从合成肽混合物和β-酪蛋白的胰蛋白酶消化产物中选择性富集磷酸肽。正如我们之前报道的，PAA膜对磷酸根阴离子具有很强的结合能力。在此，我们描述了PAA膜作为磷酸肽选择性采样吸收剂的应用。PAA膜能够高效且选择性地富集磷酸肽；例如，浓度低至4×10^(-9) M的β-酪蛋白胰蛋白酶消化产物也能被满意地检测到。与未富集肽混合物相比，PAA膜富集的磷酸化肽的质谱信号显著提高。此外，酸性肽对富集过程影响不大。结果表明，磷酸根阴离子在PAA膜上的吸附对实现对磷酸肽的高选择性富集能力起着决定性作用。同时也证明了PAA膜作为磷酸肽特异性吸收剂的可行性。
