Fragmentation patterns of protonated amino acids formed by atmospheric pressure chemical ionization

Choi, Sung‐Seen; Song, Min; Kim, Ok-Bae; Kim, Yeowool

doi:10.1002/rcm.6411

Cited by 25 publications

(25 citation statements)

References 19 publications

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“…For comparison purpose, we have also recorded the CID spectra of [M + H] + ions of corresponding free amino acids (Table S3). The fragmentation pattern observed for [M + H] + ions of free amino acids was similar to those reported in the literature …”

Section: Resultssupporting

confidence: 79%

“…The fragmentation pattern observed for [M + H] + ions of free amino acids was similar to those reported in the literature. [17][18][19][20][21][22] We observed that the [M + H] + ions of all the dimethyl amino acids were fragmented at higher collision energies than those of corresponding free amino acids. The dimethyl amino acids showed primarily the elimination of (H 2 O + CO) in addition to other specific product ions due to methyl groups on nitrogen as well as the substituent (-R) on the α-carbon of the amino acids.…”

Section: Resultsmentioning

confidence: 99%

“…The dimethyl amino acids showed primarily the elimination of (H 2 O + CO) in addition to other specific product ions due to methyl groups on nitrogen as well as the substituent (-R) on the α-carbon of the amino acids. For convenience, these compounds were divided into four groups based on the nature of -R group that include aliphatic (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12), aromatic (13)(14)(15)(16), acidic (17 and 18) and amidic or basic (19)(20)(21)(22) dimethyl amino acids. The isomeric dimethyl amino acids showed distinct spectra, which were also discussed subsequently.…”

Section: Resultsmentioning

confidence: 99%

“…The spectrum of leucine immonium ion showed the product ions at m/z 69 (7%), 44 (base peak) and 43 corresponding to the losses of NH 3 , C 3 H 6 (through a McLafferty-type rearrangement), and • C 3 H 7 radical, respectively. The spectrum of isoleucine immonium ion showed the product ions at m/z 69 (66%), 67, 58, 57, 41 and 30 corresponding to the losses of NH 3 , (NH 3 + H 2 ), (22), 111 (7), 100 (4), 98 (22), 84 (7), 70 (100), 52 (7), 44 (4), 42 (7), 41 (4) 23i; 157 (21) 140 20 114 (100), 112 (63), 97 (3), 84 (31), 58 (5), 46 (1), 44 (1) distinct product ions (Fig. 5).…”

Section: Cid Of Immonium Ionsmentioning

confidence: 99%

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Characterization of N,N‐dimethyl amino acids by electrospray ionization–tandem mass spectrometry

et al. 2015

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Methylation is an essential metabolic process for a number of critical reactions in the body. Methyl groups are involved in the healthy function of the body life processes, by conducting methylation process involving specific enzymes. In these processes, various amino acids are methylated, and the occurrence of methylated amino acids in nature is diverse. Nowadays, mass-spectrometric-based identification of small molecules as biomarkers for diseases is a growing research. Although all dimethyl amino acids are metabolically important molecules, mass spectral data are available only for a few of them in the literature. In this study, we report synthesis and characterization of all dimethyl amino acids, by electrospray ionization-tandem mass spectrometry (MS/MS) experiments on protonated molecules. The MS/MS spectra of all the studied dimethyl amino acids showed preliminary loss of H2O + CO to form corresponding immonium ions. The other product ions in the spectra are highly characteristic of the methyl groups on the nitrogen and side chain of the amino acids. The amino acids, which are isomeric and isobaric with the studied dimethyl amino acids, gave distinctive MS/MS spectra. The study also included MS/MS analysis of immonium ions of dimethyl amino acids that provide information on side chain structure, and it is further tested to determine the N-terminal amino acid of the peptides.

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Section: Resultssupporting

confidence: 79%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Cid Of Immonium Ionsmentioning

confidence: 99%

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Characterization of N,N‐dimethyl amino acids by electrospray ionization–tandem mass spectrometry

et al. 2015

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“…To target analytes containing a nonpolar hydrocarbon side chain, the main product observed is related a neutral loss of a formic acid [M + H – 46] + . On the other hand, quantifier ions of compounds such as GABA and tryptophan undergo a neutral loss of [M + H –17] + (NH 3 ).…”

Section: Resultsmentioning

confidence: 99%

Simultaneous determination of amino acids and neurotransmitters in plasma samples from schizophrenic patients by hydrophilic interaction liquid chromatography with tandem mass spectrometry

Domingues

Crevelin

Moraes

et al. 2015

J of Separation Science

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A sensitive, reproducible, and rapid method was developed for the simultaneous determination of underivatized amino acids (aspartate, serine, glycine, alanine, methionine, leucine, tyrosine, and tryptophan) and neurotransmitters (glutamate and γ-aminobutyric acid) in plasma samples using hydrophilic interaction liquid chromatography coupled to triple quadrupole tandem mass spectrometry. The plasma concentrations of amino acids and neurotransmitters obtained from 35 schizophrenic patients in treatment with clozapine (27 patients) and olanzapine (eight patients) were compared with those obtained from 38 healthy volunteers to monitor the effectiveness of treatment. The chromatographic conditions separated ten target compounds within 3 min. This method presented linear ranges that varied from (lower limit of quantification: 9.7-13.3 nmol/mL) to (upper limit of quantification: 19.4-800 nmol/mL), intra- and interassay precision with coefficients of variation lower than 10%, and relative standard error values of the accuracy ranged from -2.1 to 9.9%. The proposed method appropriately determines amino acids and neurotransmitters in plasma from schizophrenic patients. Compared with the control group (healthy volunteers), the plasma levels of methionine in schizophrenic patients treated with olanzapine are statistically significantly higher. Moreover, schizophrenic patients treated with clozapine tend to have increased plasma levels of glutamate.

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Fragmentation reactions of protonated α,ω‐diamino carboxylic acids: The importance of functional group interactions

Grossert

White

2021

J Mass Spectrom

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Protonated members of a homologous series of biologically significant α,ω‐diamino carboxylic acids were subjected to collision induced dissociation (CID). The resulting fragmentation patterns were studied using isotopic labeling, quantum mechanical computations, and pseudo MS3 experiments conducted primarily on an ion trap mass spectrometer. Each protonated α,ω‐diamino acid showed a primary neutral loss of either ammonia or water; a clear explanation was developed for the observed variation of the two losses within the series. Protonated 2,3‐diaminopropanoic acid, 2,4‐diaminobutanoic acid, and 2,7‐diaminoheptanoic acid gave secondary losses of water, carbon monoxide, and a loss of water plus carbon monoxide, respectively. In the parallel pathways characterized for the fragmentations of protonated ornithine and lysine, the α‐nitrogen of the diamino acid was maintained in the cyclic iminium product formed by successive losses of NH3 and (H2O + CO), whereas the side‐chain nitrogen was retained by consecutive losses of H2O and (CO, NH3). The 1‐piperideine ion from protonated lysine was fragmented further, losing ethylene from carbons 4 and 5. Protonated 2,6‐diaminopimelic acid fragmented by analogous reactions. Detailed mechanistic schemes for the fragmentation of both protonated 2,3‐diaminopropanoic and ornithine were generated from MP2/DFT computations. This work highlights the participation of the side‐chain amino group, which distinguishes the gas‐phase chemistry of protonated α,ω‐diamino acids from the well‐documented fragmentation reactions of protonated α‐amino acids bearing a hydrogen atom or an alkyl side chain. In general, the results further illustrate the importance of intramolecular separations affecting the specific interactions between functional groups leading to the fragmentation of multifunctional ions.

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Fragmentation patterns of protonated amino acids formed by atmospheric pressure chemical ionization

Cited by 25 publications

References 19 publications

Characterization of N,N‐dimethyl amino acids by electrospray ionization–tandem mass spectrometry

Characterization of N,N‐dimethyl amino acids by electrospray ionization–tandem mass spectrometry

Simultaneous determination of amino acids and neurotransmitters in plasma samples from schizophrenic patients by hydrophilic interaction liquid chromatography with tandem mass spectrometry

Fragmentation reactions of protonated α,ω‐diamino carboxylic acids: The importance of functional group interactions

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