Interpretation of ESI(+)-MS-MS spectra—Towards the identification of “unknowns”

Weissberg, Avi; Dagan, S.

doi:10.1016/j.ijms.2010.10.024

Cited by 66 publications

(63 citation statements)

References 23 publications

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“…3C) as recommended by (29 The nonlinear regression (fitting) was performed by the Levenberg-Marquardt method in Mathematica 8.0 software (Wol- The determined pK a,m values are 3.0 Ϯ 0.14, 5.0 Ϯ 0.14, and 6.1 Ϯ 0.2 for 9-isocitryl ester and 3.0 Ϯ 0.17, 4.9 Ϯ 0.18, and 6.1 Ϯ 0.2 for 10-isocitryl ester. Relying on the chemical shift changes, these pK a values could be assigned to carboxyl groups with atoms 1Љ(1ٞ), 6Љ(6ٞ) and 5Љ(5ٞ) of isocitryl ester moieties, in this order.…”

Section: Isolation Of Activementioning

confidence: 99%

Lignan from Thyme Possesses Inhibitory Effect on ASIC3 Channel Current

Dubinnyi

Osmakov

Koshelev

et al. 2012

Journal of Biological Chemistry

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Background: ASIC3 channels contribute to pain stimuli perception. Results: A new compound (sevanol) was isolated from thyme extract and was shown to inhibit ASIC3 current components. Conclusion: Sevanol could play a considerable role in thyme analgesic properties. Significance: The data on the structure and potency of sevanol can make a contribution to understanding the function of ASIC3 and can be helpful for developing other pharmacological substances targeting ASIC3.

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Section: Isolation Of Activementioning

confidence: 99%

Lignan from Thyme Possesses Inhibitory Effect on ASIC3 Channel Current

Dubinnyi

Osmakov

Koshelev

et al. 2012

Journal of Biological Chemistry

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“…In the case of small organic molecules containing multiple functional groups (as it is common in many pharmaceuticals, food chemicals, flavor, pesticides etc. ), it appears that the sigma bond broken during σ and σ H fragmentations is always a heteroatomic Y–X bond, with X=Hal, O, S, N… and Y=C, S, P (Scheme ).…”

Section: Introductionmentioning

confidence: 99%

From the mobile proton to wandering hydride ion: mechanistic aspects of gas‐phase ion chemistry

Bouchoux

2013

J. Mass Spectrom.

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Structural characterization of molecular species by mass spectrometry supposes the knowledge of the type of ions generated and the mechanism by which they dissociate. In this context, a need for a rationalization of electrospray ionization(+)(-) mass spectra of small molecules has been recently expressed. Similarly, at the other end of the mass scale, efforts are currently made to interpret the major fragmentation processes of protonated and deprotonated peptides and their reduced forms produced in electron capture or electron transfer experiments. Most fragmentation processes of molecular and pseudo-molecular ions produced in the ion source of a mass spectrometer may be described by a combination of several key mechanistic steps: simple bond dissociation, formation of ion-neutral complex intermediates, hydrogen atom, hydride ion or proton migrations and nucleophilic attack. Selected crucial aspects of these elementary reactions, occurring inside positively charged ions, will be recalled and illustrated by examples taken in recent mass spectrometry literature. Emphasis will be given on the protonation process and its consequence in terms of structure and energetic.

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“…Such de novo identification aims to correlate observed spectral features in MS/MS to the structures of investigated species based on established reactivity for a class of compounds [4,[6][7][8][9]. The idea of using MS/MS as stand-alone identification tool is of increasing interest and is also being addressed using other more general approaches intended to generalize dissociation pathways [10], to automate data analysis [11], or to compile spectra in databases [12,13].…”

Section: Introductionmentioning

confidence: 99%

Revisiting the Reactivity of Uracil During Collision Induced Dissociation: Tautomerism and Charge-Directed Processes

Beach

Gabryelski

2012

J. Am. Soc. Mass Spectrom.

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In our recent work towards the nontarget identification of products of nucleic acid (NA) damage in urine, we have found previous work describing the dissociation of NA bases not adequate to fully explain their observed reactivity. Here we revisit the gas-phase chemistry of protonated uracil (U) during collision induced dissociation (CID) using two modern tandem mass spectrometry techniques; quadrupole ion trap (QIT) and quadrupole time of flight (Q-TOF). We present detailed mechanistic proposals that account for all observed products of our experiments and from previous isotope labeling data, and that are supported by previous ion spectroscopy results and theoretical work. The diverse product-ions of U cannot be explained adequately by only considering the lowest energy form of protonated U as a precursor. The tautomers adopted by U during collisional excitation make it possible to relate the complex reactivity observed to reasonable mechanistic proposals and feasible product-ion structures for this small highly conjugated heterocycle. These reactions proceed from four different stable tautomers, which are excited to a specific activated precursor from which dissociation can occur via a charge-directed process through a favorable transition state to give a stabilized product. Understanding the chemistry of uracil at this level will facilitate the identification of new modified uracil derivatives in biological samples based solely on their reactivity during CID. Our integrated approach to describing ion dissociation is widely applicable to other NA bases and similar classes of biomolecules.

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Interpretation of ESI(+)-MS-MS spectra—Towards the identification of “unknowns”

Cited by 66 publications

References 23 publications

Lignan from Thyme Possesses Inhibitory Effect on ASIC3 Channel Current

Lignan from Thyme Possesses Inhibitory Effect on ASIC3 Channel Current

From the mobile proton to wandering hydride ion: mechanistic aspects of gas‐phase ion chemistry

Revisiting the Reactivity of Uracil During Collision Induced Dissociation: Tautomerism and Charge-Directed Processes

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