title: Direct characterization of intact polypeptides by matrix-assisted laser desorption electrospray ionization quadrupole Fourier transform ion cyclotron resonance mass spectrometry.
abstract: We report the characterization of a recently introduced hybrid ionization source, matrix-assisted laser desorption electrospray ionization (MALDESI), coupled to a quadrupole Fourier transform ion cyclotron resonance mass spectrometry (QFT-ICR-MS) system. We first demonstrate the ability of MALDESI-QFT-ICR MS to directly analyze and provide high mass measurement accuracy (approximately 1 part-per-million) of a polypeptide using internal calibration. Second, we show the potential of MALDESI-QFT-ICR MS for the top-down characterization of multiply charged polypeptide cations. Finally, we demonstrate sub-femtomole detection limits in MALDESI-QFT-ICR MS using a combination of naturally occurring peptides and their respective stable isotope labeled forms. The results presented herein demonstrate the feasibility of several potential applications for MALDESI-QFT-ICR MS for the direct analysis of intact biological molecules.
authors.affiliation: W. M. Keck FT-ICR Mass Spectrometry Laboratory, Department of Chemistry, North Carolina State University, Raleigh, NC 27695, USA.
authors.forename: Jason S
authors.initials: JS
authors.lastname: Sampson
authors.forename: Adam M
authors.initials: AM
authors.lastname: Hawkridge
authors.forename: David C
authors.initials: DC
authors.lastname: Muddiman
mesh_terms: D017357:Cyclotrons; D008832:Microchemistry / Q000379:methods*; D008970:Molecular Weight; D010455:Peptides / Q000737:chemistry*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods*
chemical_list: D010455:Peptides