PMID- 20855542 OWN - NLM STAT- MEDLINE VI - 10 IP - 2 TI - Laserspray ionization, a new method for protein analysis directly from tissue at atmospheric pressure with ultrahigh mass resolution and electron transfer dissociation. PG - M110.000760 LA - eng PT - Journal Article PT - Research Support, N.I.H., Extramural PT - Research Support, Non-U.S. Gov't PT - Research Support, U.S. Gov't, Non-P.H.S. PL - United States TA - Mol Cell Proteomics JT - Molecular & cellular proteomics : MCP JID - 101125647 IS - 1535-9484 (Electronic) LID - 10.1074/mcp.M110.000760 [doi] FAU - Inutan, Ellen D AU - Inutan ED AD - Department of Chemistry, Wayne State University, Detroit, Michigan 48202, USA. FAU - Richards, Alicia L AU - Richards AL FAU - Wager-Miller, James AU - Wager-Miller J FAU - Mackie, Ken AU - Mackie K FAU - McEwen, Charles N AU - McEwen CN FAU - Trimpin, Sarah AU - Trimpin S IS - 1535-9476 (Linking) RN - 0 (Acetophenones) RN - 0 (Proteins) RN - 65328I5OQP (2,6-dihydroxyacetophenone) SB - IM MH - Acetophenones/chemistry MH - Animals MH - Atmospheric Pressure MH - Brain/*metabolism MH - Electrons MH - Fourier Analysis MH - Mass Spectrometry/methods MH - Mice MH - Mice, Inbred C57BL MH - Proteins/*chemistry MH - Proteomics/methods MH - Reproducibility of Results MH - Spectrometry, Mass, Electrospray Ionization/methods PMC - PMC3033668 DCOM- 20110721 LR - 20211020 DP - 2011 Feb DEP - 20100920 AB - Laserspray ionization (LSI) mass spectrometry (MS) allows, for the first time, the analysis of proteins directly from tissue using high performance atmospheric pressure ionization mass spectrometers. Several abundant and numerous lower abundant protein ions with molecular masses up to ∼20,000 Da were detected as highly charged ions from delipified mouse brain tissue mounted on a common microscope slide and coated with 2,5-dihydroxyacetophenone as matrix. The ability of LSI to produce multiply charged ions by laser ablation at atmospheric pressure allowed protein analysis at 100,000 mass resolution on an Orbitrap Exactive Fourier transform mass spectrometer. A single acquisition was sufficient to identify the myelin basic protein N-terminal fragment directly from tissue using electron transfer dissociation on a linear trap quadrupole (LTQ) Velos. The high mass resolution and mass accuracy, also obtained with a single acquisition, are useful in determining protein molecular weights and from the electron transfer dissociation data in confirming database-generated sequences. Furthermore, microscopy images of the ablated areas show matrix ablation of ∼15 μm-diameter spots in this study. The results suggest that LSI-MS at atmospheric pressure potentially combines speed of analysis and imaging capability common to matrix-assisted laser desorption/ionization and soft ionization, multiple charging, improved fragmentation, and cross-section analysis common to electrospray ionization.