Journal article

Oxidative Damage of S-Containing Amino Acids by the Environmental Radical NO3.: A Kinetic, Product and Computational Study

Jiaxing Cui, Joses G Nathanael, Uta Wille

CHEMISTRYSELECT | WILEY-V C H VERLAG GMBH | Published : 2021

Abstract

Methionine, cysteine and cystine, which were acetylated at the N-terminus and methylated at the C-terminus, react rapidly with the environmental nitrate radical (NO3.) with rate coefficients of 7.7×109, 3.4×109 and 2.0×109 M−1 s−1, respectively, in acetonitrile. Methionine (Ac−Met−OMe) is successively oxidized via the sulfoxide (Ac−MetO−Me) to the sulfone (Ac−MetO2−OMe), with the latter step being also extremely fast with a rate coefficient of 1.2×109 M−1 s−1. Computations predict formation of an initial charge transfer complex between NO3. and the S or SO moiety in Ac-Met-OMe, Ac-MetO-OMe and cystine (Ac−Cys(S−S)Cys-OMe), respectively, which is followed by simultaneous S−O bond formation an..

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Grants

Funding Acknowledgements

This work was supported by the Australian Research Council through the Linkage, Infrastructure, Equipment and Facilities (LIEF) Grant Scheme and The University of Melbourne through the High-Performance Computing Facility.[47] We thank Mr Cameron Ong for his support and Dr Lars Goerigk for helpful discussions.