Detection of protein oxidation products by fluorescence spectroscopy and trilinear data decomposition: Proof of concept

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Abstract

Current analytical methods studying protein oxidation modifications require laborious sample preparation and chromatographic methods. Fluorescence spectroscopy is an alternative, as many protein oxidation products are fluorescent. However, the complexity of the signal causes misinterpretation and quantification errors if single emission spectra are used. Here, we analyzed the entire fluorescence excitation-emission matrix using the trilinear decomposition method parallel factor analysis (PARAFAC). Two sample sets were used: a calibration set based on known mixtures of tryptophan, tyrosine, and four oxidation products, and a second sample set of oxidized protein solutions containing UV-illuminated β-lactoglobulin. The PARAFAC model succeeded in resolving the signals of the model systems into the pure fluorophore components and estimating their concentrations. The estimated concentrations for the illuminated β-lactoglobulin samples were validated by liquid chromatography-mass spectrometry. Our approach is a promising tool for reliable identification and quantification of fluorescent protein oxidation products, even in a complex protein system.

Original languageEnglish
Article number133732
JournalFood Chemistry
Volume396
Number of pages9
ISSN0308-8146
DOIs
Publication statusPublished - 2022

Bibliographical note

Publisher Copyright:
© 2022 The Author(s)

Keywords

  • 3,4-dihydroxy-L-phenylalanine (PubChem CID: 6047)
  • 5-hydroxy-L-Trp (PubChem CID: 439280)
  • dityrosine (PubChem CID: 107904)
  • Excitation-Emission matrix
  • Fluorescence spectroscopy
  • N-formylkynurenine (PubChem CID: 910)
  • Parallel Factor Analysis (PARAFAC)
  • Protein oxidation
  • Second order advantage
  • Tryptophan (PubChem CID: 6305)
  • tyrosine (PubChem CID: 1153)
  • β-lactoglobulin

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