Mass Spectrometry in Structural and Stereochemical Problems. LXV.1Synthesis and Fragmentation Behavior of 15-Keto Steroids. The Importance of Interatomic Distance in the McLafferty Rearrangement2

1965 ◽  
Vol 87 (4) ◽  
pp. 817-826 ◽  
Author(s):  
Carl Djerassi ◽  
G. von Mutzenbecher ◽  
J. Fajkos ◽  
D. H. Williams ◽  
H. Budzikiewicz
Keyword(s):  
Mass Spectrometry ◽  
Interatomic Distance ◽  
Fragmentation Behavior

scholarly journals Characterization of a novel + 70 Da modification in rhGM-CSF expressed in E. coli using chemical assays in combination with mass spectrometry

Amino Acids ◽  
2021 ◽  
Author(s):  
Magdalena Widgren Sandberg ◽  
Jakob Bunkenborg ◽  
Stine Thyssen ◽  
Martin Villadsen ◽  
Thomas Kofoed
Keyword(s):  
Mass Spectrometry ◽  
Tandem Mass Spectrometry ◽  
Peptide Mapping ◽  
Covalent Modification ◽  
Peptide Fragmentation ◽  
Tandem Mass ◽  
E Coli ◽  
Gm Csf ◽  
Fragmentation Behavior ◽  
Macrophage Colony

AbstractGranulocyte-macrophage colony-stimulating factor (GM-CSF) is a cytokine and a white blood cell growth factor that has found usage as a therapeutic protein. During analysis of different fermentation batches of GM-CSF recombinantly expressed in E. coli, a covalent modification was identified on the protein by intact mass spectrometry. The modification gave a mass shift of + 70 Da and peptide mapping analysis demonstrated that it located to the protein N-terminus and lysine side chains. The chemical composition of C4H6O was found to be the best candidate by peptide fragmentation using tandem mass spectrometry. The modification likely contains a carbonyl group, since the mass of the modification increased by 2 Da by reduction with borane pyridine complex and it reacted with 2,4-dinitrophenylhydrazine. On the basis of chemical and tandem mass spectrometry fragmentation behavior, the modification could be attributed to crotonaldehyde, a reactive compound formed during lipid peroxidation. A low recorded oxygen pressure in the reactor during protein expression could be linked to the formation of this compound. This study shows the importance of maintaining full control over all reaction parameters during recombinant protein production.

Changes in Post-Source Decay Fragmentation Behavior of Poly(Methyl Methacrylate) Polymers with Increasing Molecular Weight Studied by Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry

2003 ◽  
Vol 9 (3) ◽  
pp. 195-201 ◽  
Author(s):  
Olli Laine ◽  
Sarah Trimpin ◽  
Hans Joachim Räder ◽  
Klaus Müllen
Keyword(s):  
Mass Spectrometry ◽  
Molecular Weight ◽  
Laser Desorption ◽  
Laser Desorption Ionization ◽  
Post Source Decay ◽  
Ionization Time ◽  
Fragmentation Behavior ◽  
Desorption Ionization ◽  
Matrix Assisted Laser ◽  
Matrix Assisted Laser Desorption

In order to investigate the systematic changes in fragmentation behavior of poly(methyl methacrylate) (PMMA) with increasing molecular weight, alkali–metal cationized PMMA 20-mer, 60-mer and 100-mer were selected for post-source decay (PSD) fragmentation study by matrix-assisted laser desorption/ionization time-of-flight (MALDI-ToF) mass spectrometry. PMMA polymers were cationized with lithium, potassium and cesium cations to explore the influence of the cation size on the fragmentation behavior of the polymers. All PMMA polymers could be fragmented by MALDI-PSD and fragmentation of the MALDI ionized synthetic polymer of molecular weight 10 kDa is reported here for the first time. It was shown that an increasing molecular weight of the PMMA chain required an increase in the size of the cation to improve the intensity and the number of the fragments in the PSD spectrum. Some instrumental parameters had to be optimized prior to a successful PSD analysis of the largest PMMA polymers.

Identification of Phosphorylcholine-Substituted Peptides by Their Characteristic Mass Spectrometric Fragmentation

2005 ◽  
Vol 11 (3) ◽  
pp. 335-344 ◽  
Author(s):  
Julia Grabitzki ◽  
Volker Sauerland ◽  
Rudolf Geyer ◽  
Günter Lochnit
Keyword(s):  
Mass Spectrometry ◽  
Ion Trap ◽  
Neutral Loss ◽  
Structural Data ◽  
Mass Spectrometric ◽  
Peptide Backbone ◽  
Fragmentation Behavior ◽  
Flight Mass Spectrometry ◽  
Characteristic Fragmentation ◽  
Fragmentation Patterns

Phosphorylcholine (PC)-substituted biomolecules are wide-spread, highly relevant antigens of parasites, since this small hapten has been found to be a potent immunomodulatory component which allows the establishment of long lasting infections of the host. Structural data, especially of protein bound PC-substituents, are still rare due to the observation that mass spectrometric analyses are mostly hampered by this zwitterionic substituent resulting in low sensitivities and unusual but characteristic fragmentation patterns. Here, we investigated the fragmentation behavior of synthetic PC-substituted peptides by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and electrospray ionization ion-trap mass spectrometry. We could show that the predominant neutral loss of a trimethylamine unit (Hoffmann elimination) leads to cyclic phosphate derivatives which prevent further fragmentation of the peptide backbone by stabilizing the positive charge at this particular side chain. Knowledge of this PC-specific fragmentation might help to identify PC-substituted biomolecules and facilitate their structural analysis.

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