FOM Institute for Atomic and Molecular Physics, Amsterdam, The Netherlands.
J Am Soc Mass Spectrom. 2010 Mar;21(3):338-47. doi: 10.1016/j.jasms.2009.09.016. Epub 2009 Sep 29.
MALDI imaging mass spectrometry (MALDI-IMS) has become a powerful tool for the detection and localization of drugs, proteins, and lipids on-tissue. Nevertheless, this approach can only perform identification of low mass molecules as lipids, pharmaceuticals, and peptides. In this article, a combination of approaches for the detection and imaging of proteins and their identification directly on-tissue is described after tryptic digestion. Enzymatic digestion protocols for different kinds of tissues--formalin fixed paraffin embedded (FFPE) and frozen tissues--are combined with MALDI-ion mobility mass spectrometry (IM-MS). This combination enables localization and identification of proteins via their related digested peptides. In a number of cases, ion mobility separates isobaric ions that cannot be identified by conventional MALDI time-of-flight (TOF) mass spectrometry. The amount of detected peaks per measurement increases (versus conventional MALDI-TOF), which enables mass and time selected ion images and the identification of separated ions. These experiments demonstrate the feasibility of direct proteins identification by ion-mobility-TOF IMS from tissue. The tissue digestion combined with MALDI-IM-TOF-IMS approach allows a proteomics "bottom-up" strategy with different kinds of tissue samples, especially FFPE tissues conserved for a long time in hospital sample banks. The combination of IM with IMS marks the development of IMS approaches as real proteomic tools, which brings new perspectives to biological studies.
基质辅助激光解吸电离成像质谱（MALDI-IMS）已成为在组织上检测和定位药物、蛋白质和脂质的有力工具。然而，这种方法只能识别低质量分子，如脂质、药物和肽。在本文中，描述了一种在胰蛋白酶消化后直接在组织上检测和成像蛋白质并对其进行鉴定的组合方法。将不同类型组织（福尔马林固定石蜡包埋（FFPE）和冷冻组织）的酶消化方案与 MALDI-离子淌度质谱（IM-MS）相结合。这种组合能够通过相关的消化肽来定位和鉴定蛋白质。在许多情况下，离子淌度可分离常规 MALDI 飞行时间（TOF）质谱无法识别的等质异位离子。与传统的 MALDI-TOF 相比，检测到的峰数量增加（相对于传统 MALDI-TOF），从而能够进行质量和时间选择的离子图像和分离离子的鉴定。这些实验证明了通过组织的离子淌度-TOF IMS 直接进行蛋白质鉴定的可行性。组织消化与 MALDI-IM-TOF-IMS 方法的结合允许使用不同类型的组织样本进行蛋白质组学“自上而下”策略，特别是在医院样本库中长时间保存的 FFPE 组织。离子淌度与 IMS 的结合标志着 IMS 方法作为真正的蛋白质组学工具的发展，为生物学研究带来了新的视角。
