Simpson, Joanna P., Fascione, Martin orcid.org/0000-0002-0066-4419, Bergström, Ed et al. (4 more authors) (2019) Ionisation bias undermines the use of matrix-assisted laser desorption/ionisation for estimating peptide deamidation:Synthetic peptide studies demonstrate electrospray ionisation gives more reliable response ratios. Rapid Communications in Mass Spectrometry. pp. 1049-1057. ISSN 1097-0231
Abstract
RATIONALE: Although mass spectrometry is routinely used to determine deamination in peptide mixtures, the effects of ionisation source choice have not yet been investigated. In particular, matrix-assisted laser desorption/ionisation (MALDI) has become a popular tool with which to measure levels of glutamine deamidation in ancient proteins. Here we use model synthetic peptides to rigorously compare MALDI and electrospray ionisation. METHODS: We use two synthetic peptides, with glutamine (Q) in one substituted for glutamic acid (E) in the other, to investigate the suitability of MALDI and ESI sources for the assessment of deamidation in peptides using mass spectrometry. We also compare measurements of the same Q and E-containing peptide mixtures using two different mass analysers (time of flight and Fourier-transform ion cyclotron resonance). RESULTS: When standard mixtures of the Q- and E-containing peptides were analysed using MALDI, under-representation of the E-containing peptide was observed. This observation was consistent between analyses carried out using either TOF or FT-ICR-MS. When the same mixtures were analysed using ESI FT-ICR-MS, no ionisation bias was observed. CONCLUSIONS: MALDI may not be a suitable ionisation method for the determination of deamidation in peptide mixtures. However, ESI was successfully used to determine the ratio in known mixtures of Q and E containing peptides. These preliminary observations warrant further investigation into ionisation bias when measuring deamidation in other peptide sequences.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2019 The Authors |
Dates: |
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Institution: | The University of York |
Academic Units: | The University of York > Faculty of Sciences (York) > Chemistry (York) The University of York The University of York > Faculty of Sciences (York) > Mathematics (York) The University of York > Faculty of Arts and Humanities (York) > Archaeology (York) |
Depositing User: | Pure (York) |
Date Deposited: | 22 Mar 2019 12:40 |
Last Modified: | 14 Mar 2025 00:08 |
Published Version: | https://doi.org/10.1002/rcm.8441 |
Status: | Published |
Refereed: | Yes |
Identification Number: | 10.1002/rcm.8441 |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:143990 |
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Description: Ionisation bias undermines the use of matrix‐assisted laser desorption_ionisation for estimating peptide deamidation_ Synthetic peptide studies demonstrate electrospray ionisation gives more reliable response ratios - Simpson -
Licence: CC-BY 2.5