Identification of modified lysozyme peptides upon photo-oxidation by LC-TOF-MS

Area of Science:

• Food science and technology
• Biochemistry
• Analytical chemistry

Background:

• Protein oxidation significantly impacts food quality and safety.
• Current methods for assessing oxidative damage often lack specificity.
• Identifying specific oxidation markers is essential for accurate food analysis.

Purpose of the Study:

• To identify specific peptide markers for protein oxidation.
• To investigate the impact of photo-oxidation on lysozyme.
• To establish reliable indicators for protein oxidative damage.

Main Methods:

• Photo-oxidation of lysozyme.
• Hydrolysis of modified lysozyme.
• Peptide analysis using Liquid Chromatography-Time of Flight Mass Spectrometry (LC-TOF-MS).
• Semi-quantitative analysis of peptide modifications.

Main Results:

• Two specific peptides, HGLDNYR and WWCNDGR, were identified as highly susceptible to photo-oxidation.
• These peptides show potential as specific markers for protein oxidation.
• Site-specific modifications provided insights into lysozyme degradation pathways.
• Surrounding amino acids and protein 3D structure influence modification susceptibility.

Conclusions:

• The peptides HGLDNYR and WWCNDGR can serve as specific markers for protein oxidation.
• Evaluating protein oxidation on intact proteins is advisable for accurate assessment.
• Understanding modification pathways aids in predicting and managing food quality.