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
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..View full abstract
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. We thank Mr Cameron Ong for his support and Dr Lars Goerigk for helpful discussions.