title: Highly specific capture and direct MALDI-MS analysis of phosphorylated peptides using novel multifunctional chitosan-GMA-IDA-Fe (III) nanosphere.
abstract: In this study, we describe a method for highly specific enrichment of phosphopeptides with multifunctional chitosan-glycidyl methacrylate (GMA)-iminodiacetic acid (IDA)-Fe (III) nanospheres for direct analysis by matrix-assisted laser desorption-ionization mass spectrometry (MALDI-MS). This is the first time that chitosan has been used to create nanospheres support material for selective enrichment of phosphopeptides by modification with GMA, derivatization with IDA, and loading with Fe (III) ions. Chitosan-GMA-IDA-Fe (III) nanospheres with a diameter of 20 to 100 nm have multifunctional chemical moieties which confer unique properties, good dispersibility in highly acidic binding buffers, as well as good biocompatibility and chemical stability which improves their specific interaction with phosphopeptides using various types of acid binding buffers. The process of enrichment is very simple, quick, efficient, and specific. Its high specificity and efficiency for purification of phosphopeptides is reflected in the very low and substoichiometric amounts of phosphopeptides which can be detected, in quantities as low as 1:3,000 M ratios. Compared with other state-of the-art technologies such as the use of conventional Fe(3+)-IMAC and TiO(2), these chitosan nanosphere techniques show superior specificity and sensitivity. Moreover, the resultant chitosan-GMA-IDA-Fe(3+) nanosphere-absorbed phosphopeptides can be either directly analyzed by MALDI-TOF MS analysis or eluted and further analyzed by nano-LC-MS/MS.
authors: Proteomics Laboratory, Medical and Healthy Analytical Center, Peking University, Beijing, China. zouxj@bjmu.edu.cn
authors: Xiajuan
authors: X
authors: Zou
authors: Dan
authors: D
authors: Liu
authors: Lijun
authors: L
authors: Zhong
authors: Bin
authors: B
authors: Yang
authors: Yaxin
authors: Y
authors: Lou
authors: Baihe
authors: B
authors: Hu
authors: Yuxin
authors: Y
authors: Yin
mesh_terms: D000818:Animals; D048271:Chitosan / Q000737:chemistry*; D007098:Imino Acids / Q000737:chemistry*; D007501:Iron / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry; D008689:Methacrylates / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D015394:Molecular Structure; D054118:Nanospheres / Q000737:chemistry*; D010748:Phosphopeptides / Q000737:chemistry*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D007098:Imino Acids; D008689:Methacrylates; D010748:Phosphopeptides; C528054:glycidyl methacrylate-iminodiacetic acid; D048271:Chitosan; D007501:Iron