39871 2017 eng 2411 2420 9 409 article Springer Heidelberg 1 -- -- -- Hydroxyl radical-induced oxidation of proteins and peptides can lead to the cleavage of the peptide, leading to a release of fragments. Here, we used high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) and pre-column online ortho-phthalaldehyde (OPA) derivatization-based amino acid analysis by HPLC with diode array detection and fluorescence detection to identify and quantify free amino acids released upon oxidation of proteins and peptides by hydroxyl radicals. Bovine serum albumin (BSA), ovalbumin (OVA) as model proteins, and synthetic tripeptides (comprised of varying compositions of the amino acids Gly, Ala, Ser, and Met) were used for reactions with hydroxyl radicals, which were generated by the Fenton reaction of iron ions and hydrogen peroxide. The molar yields of free glycine, aspartic acid, asparagine, and alanine per peptide or protein varied between 4 and 55%. For protein oxidation reactions, the molar yields of Gly (∼32-55% for BSA, ∼10-21% for OVA) were substantially higher than those for the other identified amino acids (∼5-12% for BSA, ∼4-6% for OVA). Upon oxidation of tripeptides with Gly in C-terminal, mid-chain, or N-terminal positions, Gly was preferentially released when it was located at the C-terminal site. Overall, we observe evidence for a site-selective formation of free amino acids in the OH radical-induced oxidation of peptides and proteins, which may be due to a reaction pathway involving nitrogen-centered radicals. Analytical and Bioanalytical Chemistry 10.1007/s00216-017-0188-y http://link.springer.com/article/10.1007%2Fs00216-017-0188-y 1618-2650 1618-2642 urn:nbn:de:kobv:b43-398714 18.04.2017 Creative Commons - Namensnennung 3.0 F. Liu S. Lai H. Tong P. S. J. Lakey M. Shiraiwa Michael G. Weller U. Pöschl C. J. Kampf eng uncontrolled Peptides eng uncontrolled Proteins eng uncontrolled Oxidation eng uncontrolled Hydroxyl radicals eng uncontrolled LC-MS eng uncontrolled Amino acid analysis eng uncontrolled Bovine serum albumin eng uncontrolled Ovalbumin eng uncontrolled Tripeptides eng uncontrolled Ortho-Phthalaldehyde eng uncontrolled AAA eng uncontrolled Degradation eng uncontrolled Fragmentation eng uncontrolled Mechanism Analytische Chemie Sanitär- und Kommunaltechnik; Umwelttechnik Verlagsliteratur Datei für die Öffentlichkeit verfügbar ("Open Access") Wissenschaftliche Artikel der BAM Bundesanstalt für Materialforschung und -prüfung (BAM) https://opus4.kobv.de/opus4-bam/files/39871/Liu-2017-ABC release of free amino acids upon oxidation of peptides and proteins by hydroxyl radicals.pdf