Mass spectrometric sequencing of linear peptides by product‐ion analysis in a reflectron time‐of‐flight mass spectrometer using matrix‐assisted laser desorption ionization

Abstract

In matrix-assisted laser desorption ionization (MALDI) a large fraction of analyte ions undergo post-source decay (PSD) during flight in the field-free drift path. By means of a modified two-stage reflectron, product ion time-of-flight spectra of medium-sized linear peptides (up to 2800 u) were recorded, containing full sequence information. Precision, accuracy and mass resolution of fragment ions were almost as good as obtained in high-energy collisionally activated dissociation (CAD) studies performed in four-sector instruments. Instrumental sensitivity was better by at least one order of magnitude. In reflectron time-of-flight mass spectrometry (RETOFMS) the cleavage pattern of PSD products is different from that obtained by high-energy and low-energy CAD. Activation mechanisms of PSD were found to be largely determined by collisional events (ion/neutral) occurring in the acceleration field during early plume expansion. Future potentials of PSD analysis after MALDI are discussed.

Determination of the disulfide bond arrangement of human respiratory syncytial virus attachment (G) protein by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry

“…Analysis of metastable ions arising from post-source decay of peptic peptide 2 prepared in matrix 1 was performed using 20 step-wise decrements in the reflectron potential and increasing the laser irradiance to optimize production of ions in each voltage window (Spengler et al, 1992;Kaufmann et al, 1993Kaufmann et al, , 1994. Masses were assigned to metastable ions by reference to a calibration table created by determining the behavior of metastable ions of known mass, produced from adrenocorticotropic hormone residues 18-39, at various reflectron potentials (Rouse et al, 1995).…”

Development of new methodologies for the mass spectrometry study of bioorganic macromolecules

“…That phenomenon can be used to obtain structural details by collecting data with the TOF analyzer in the reflectron mode. That technique has been named post-source decay (PSD) (Kaufmann, Spengler, & Lutzenkirchen, 1993;Hellman & Bhikhabhai, 2002). FIGURE 1. MALDI mass spectrum of a protein mixture containing cytochrome c, ribonuclease A, lysozime, and myoglobin.…”

An endogenous proteinacious inhibitor in porcine liver for S-adenosyl-l-methionine dependent methylation reactions: identification as oligosaccharide-linked acyl carrier protein

“…Data acquisition was performed by a transient recorder at 10 ns sampling rate and 10 Hz duty cycle. Fifty-one hundred spectra were summed for each re¯ector setting [18]. The sequence of 7,400 Da was found to be completely identical to the known sequence of spinach ACP with a single exception, residue-77 (Table 1).…”

“…In a single-stage TOF-MS, a simple relationship exists between the¯ight time and fragment-ion mass. Based on such sets of data and the actual ight times of precursor and fragment ions recorded, a computer can calculate the fragmention masses to the desired accuracy by iteration [18]. In practice, an algorithm was integrated into our PC-based TOF-MS data acquisition and processing software (Grams/32 Array Basic, Ver 4.0, Galactic industries Corporation, USA).…”