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The Fate of Sulfur Radical Cation of N-Acetyl-Methionine: Deprotonation vs. Decarboxylation.

Authors :
Grzyb, Katarzyna
Sehrawat, Vidhi
Pedzinski, Tomasz
Source :
Photochem; Mar2023, Vol. 3 Issue 1, p98-108, 11p
Publication Year :
2023

Abstract

In the present study, we investigated the photooxidation of the biomimetic model of C-terminal methionine, N-Acetyl-Methionine (N-Ac-Met), sensitized by a 3-Carboxybenzophenone (3CB) excited triplet in neutral and basic aqueous solutions. The short-lived transient species that formed in the reaction were identified and quantified by laser flash photolysis and the final stable products were analyzed using liquid chromatography coupled with high-resolution mass spectrometry (LC-MS) and tandem mass spectrometry (MSMS). Based on these complementary methods, it was possible to calculate the quantum yields of both competing reactions, and the deprotonation was found to be favored over decarboxylation (for neutral pH: ϕ<subscript>-H</subscript> = 0.23 vs. ϕ<subscript>-CO2</subscript> = 0.09, for basic pH: ϕ<subscript>-H</subscript> = 0.23 vs. ϕ<subscript>-CO2</subscript> = 0.05). Findings on such a model system, which can possibly mimic the complex protein environment, are important in understanding complicated biological systems, for example, the studied compound, N-Ac-Met, can, to some extent, mimic the methionine in the C-terminal domain of β-amyloid, which is thought to be connected with the pathogenesis of Alzheimer's disease. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
26737256
Volume :
3
Issue :
1
Database :
Complementary Index
Journal :
Photochem
Publication Type :
Academic Journal
Accession number :
162807982
Full Text :
https://doi.org/10.3390/photochem3010007