Formation and characterization of crosslinks, including Tyr–Trp species, on one electron oxidation of free Tyr and Trp residues by carbonate radical anion

Abstract

<p>Exposure of free Tyr and Trp to a high concentration of carbonate anion radicals (CO₃˙⁻), under anaerobic conditions, result in the formation of Tyr–Trp species, as well as dityrosine and ditryptophan crosslinks.</p>

Oxidative Crosslinking of Peptides and Proteins: Mechanisms of Formation, Detection, Characterization and Quantification

“…•− -mediated di-Trp crosslinks have also been reported for both free Trp [158] and lysozyme [79]. In the latter case, oxidation mediated by hSOD1 resulted in the detection of both hetero-dimers of lysozyme with hSOD1 and hSOD1 dimers [79].…”

“…The free amino acids and crosslinked products obtained from hydrolysis are separated by HPLC/UPLC and can be quantified by MS [158,159,193], by fluorescence detection (directly for di-Tyr [51], or by pre-column tagging for parent amino acids using sensitive fluorescent tags such as o-phthaldialdehyde [191]), UV absorption, or, for some species, electrochemical oxidation [191,195]. For HPLC/UPLC methodologies coupled to MS detection, heavy atom labeling (usually 2 H, 13 C, or 15 N) can be utilized for accurate quantification [193].…”

“…This results in irreversible dimerization and is associated with non-amyloid protein aggregation and the occurrence of amyotrophic lateral sclerosis (ALS) [ 157 ]. CO 3 •− -mediated di-Trp crosslinks have also been reported for both free Trp [ 158 ] and lysozyme [ 79 ]. In the latter case, oxidation mediated by hSOD1 resulted in the detection of both hetero-dimers of lysozyme with hSOD1 and hSOD1 dimers [ 79 ].…”

“…•− have provided evidence for three different, isomeric, Tyr-Trp crosslinks, with these likely to involve carbon-carbon bonds, and probably between the ortho (C3) position on the Tyr ring, and C3 on the indole ring of Trp [158].…”

l‐Tryptophan Interactions with the Horseradish Peroxidase‐Catalyzed Generation of Triplet Acetone

“…This research allows us to propose the potential ability of carbonyl triplets generated by dioxetane and alkyl-oxy and alkyl peroxyl radical intermediates to drive typically photochemical reactions of biomolecules in the absence of light, proposed by the hypothesis of "photobiochemistry in the dark" (4)(5)(6)8,44). Redox-active amino acids present in free cells, protein residues or membrane-bound cells may be preferential targets of radicals and chemiexcited species and activate a broad spectrum of biological responses, including protein cross-linking, carbonylation and impairment of redox balance (45).…”