A computational and experimental study of the fragmentation of <scp>l</scp>-leucine, <scp>l</scp>-isoleucine and <scp>l</scp>-allo-isoleucine under collision-induced dissociation tandem mass spectrometry

Jiang, Candy; Arthur, Christopher J.; Gates, Paul J.

doi:10.1039/d0an00778a

Cited by 9 publications

(9 citation statements)

References 28 publications

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“…From the product ion observed at m / z 142.1 and discussed in the previous section, the ions [PCP(A) – C 3 H 8 O 2 NP] + observed at m / z 140.1 and [PCP(A) – C 3 H 6 O 2 NP – HCl] + observed at m / z 106.1 may be obtained by the elimination of H 2 and HCl as shown in Figure A,B, respectively. The elimination of H 2 from amino acids and nucleobases in CID experiments employing positive mode ESI has been previously reported in the literature. − Such secondary reactions are experimentally viable in our work due to the high collision pressures employed in the CID conditions, which does not preclude multiple collision scenarios.…”

Section: Resultsmentioning

confidence: 56%

Analysis of the Fragmentation Pathways for the Collision-Induced Dissociation of Protonated Cyclophosphamide: A Mass Spectrometry and Quantum Mechanical Study

Korany

Ritacco

Dabbish

et al. 2022

J. Chem. Inf. Model.

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Cyclophosphamide is a well-known anticancer agent acting by means of DNA alkylation. Associated with its tumor selectivity, it also possesses a wide spectrum of toxicities. As the requirement of metabolic activation before cyclophosphamide exerts either its therapeutic or toxic effects is well recognized, research aiming at elucidating the pathways that lead to the activation of this drug is of key importance. This has created the necessity for developing an effective analytical method for detecting cyclophosphamide and its breakdown products. In this paper, an Acquity TQ tandem quadrupole mass spectrometer equipped with electrospray ionization in positive-ion mode was employed for detecting cyclophosphamide in its protonated form. The full-scan mass spectrum of cyclophosphamide shows two ion clusters displaying the characteristic isotopic pattern of two chlorine atoms and assigned as sodiated cyclophosphamide, [CP + Na]+, and protonated cyclophosphamide, [CP + H]+ or PCP. With the aid of quantum mechanical DFT calculation, free energy differences in the gas phase among PCP protomers were computed with respect to the most stable protomer being protonated on the 2-oxide oxygen of the 1,3,2-oxazaphosphorine-2-oxide ring. In addition, the interconversion mechanisms among the different protomers were also proposed by intercepting the corresponding transition states in the gas phase. Collision-induced dissociation (CID) of PCP generated six characteristic product ions. Fragmentation mechanisms were proposed and supported by computation. The calculated energy barriers for all of the located transition states were found to be accessible under the reported experimental conditions.

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Section: Resultsmentioning

confidence: 56%

Analysis of the Fragmentation Pathways for the Collision-Induced Dissociation of Protonated Cyclophosphamide: A Mass Spectrometry and Quantum Mechanical Study

Korany

Ritacco

Dabbish

et al. 2022

J. Chem. Inf. Model.

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“…However, comprehensive studies investigating PQ's antimicrobial chemicals are still scarce, and the NMR chemical identification usually required milligrams of pure compound, which is time-consuming to purify. In recent years, the advanced Orbitrap Elite Hybrid Mass Spectrometer, which combines a novel high-field orbitrap mass analyzer with a premier dual-pressure linear ion trap mass spectrometer, greatly improved MS and MS n performance and versatility, and it has become a reliable technique for a targeted and a non-targeted analysis of the chemical structure, requiring only picogram of the sample (Denisov et al, 2012;Jiang et al, 2020;Zhao et al, 2020). LC-HRMS/MS (high-resolution mass spectrometry) and MS n provide retention time, extract m/z and its fragmentation, from which the structure normally can be inferred based on comparison with standards, or published spectra of compound databases, MS/MS libraries, and molecular networking (Allen et al, 2014;Schymanski et al, 2014;Fisher et al, 2021).…”

Section: Introductionmentioning

confidence: 99%

Bioassay-Guided Interpretation of Antimicrobial Compounds in Kumu, a TCM Preparation From Picrasma quassioides’ Stem via UHPLC-Orbitrap-Ion Trap Mass Spectrometry Combined With Fragmentation and Retention Time Calculation

Peng

et al. 2021

Front. Pharmacol.

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The stem of Picrasma quassioides (PQ) was recorded as a prominent traditional Chinese medicine, Kumu, which was effective for microbial infection, inflammation, fever, and dysentery, etc. At present, Kumu is widely used in China to develop different medicines, even as injection (Kumu zhusheye), for combating infections. However, the chemical basis of its antimicrobial activity has still not been elucidated. To examine the active chemicals, its stem was extracted to perform bioassay-guided purification against Staphylococcus aureus and Escherichia coli. In this study, two types of columns (normal and reverse-phase) were used for speedy bioassay-guided isolation from Kumu, and the active peaks were collected and identified via an UHPLC-Orbitrap-Ion Trap Mass Spectrometer, combined with MS Fragmenter and ChromGenius. For identification, the COCONUT Database (largest database of natural products) and a manually built PQ database were used, in combination with prediction and calculation of mass fragmentation and retention time to better infer their structures, especially for isomers. Moreover, three standards were analyzed under different conditions for developing and validating the MS method. A total of 25 active compounds were identified, including 24 alkaloids and 1 triterpenoid against S. aureus, whereas only β-carboline-1-carboxylic acid and picrasidine S were active against E. coli. Here, the good antimicrobial activity of 18 chemicals was reported for the first time. Furthermore, the spectrum of three abundant β-carbolines was assessed via their IC50 and MBC against various human pathogens. All of them exhibited strong antimicrobial activities with good potential to be developed as antibiotics. This study clearly showed the antimicrobial chemical basis of Kumu, and the results demonstrated that HRMS coupled with MS Fragmenter and ChromGenius was a powerful tool for compound analysis, which can be used for other complex samples. Beta-carbolines reported here are important lead compounds in antibiotic discovery.

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“…Different protein and non-protein amino acids were unequivocally identified by comparing their retention time and MS/MS fragmentation pattern with those obtained for commercial standards. ), and 44 (C 2 H 6 N + ) (Jiang et al, 2020) which were also found in Leucine commercial standard. The content of pyroglutamic acid in all the alkalization degrees studied was similar and lower than that obtained in CN, but a clear trend with the alkalization degree was not observed.…”

Section: Tablementioning

confidence: 56%

Assessment of cocoa powder changes during the alkalization process using untargeted metabolomics

Greño

Herrero

Cifuentes

et al. 2022

LWT

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A computational and experimental study of the fragmentation of l-leucine, l-isoleucine and l-allo-isoleucine under collision-induced dissociation tandem mass spectrometry

Abstract: The isomeric amino acids leucine, isoleucine and L-allo-isoleucine, are essential to many vital biological processes and are therefore of interest to the fields of metabolomics and proteomics. Their discrimination can...

Cited by 9 publications

References 28 publications

Analysis of the Fragmentation Pathways for the Collision-Induced Dissociation of Protonated Cyclophosphamide: A Mass Spectrometry and Quantum Mechanical Study

Analysis of the Fragmentation Pathways for the Collision-Induced Dissociation of Protonated Cyclophosphamide: A Mass Spectrometry and Quantum Mechanical Study

Bioassay-Guided Interpretation of Antimicrobial Compounds in Kumu, a TCM Preparation From Picrasma quassioides’ Stem via UHPLC-Orbitrap-Ion Trap Mass Spectrometry Combined With Fragmentation and Retention Time Calculation

Assessment of cocoa powder changes during the alkalization process using untargeted metabolomics

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