Journal article

Oxidative Damage in Aliphatic Amino Acids and Di- and Tripeptides by the Environmental Free Radical Oxidant NO3 center dot: The Role of the Amide Bond Revealed by Kinetic and Computational Studies

Joses G Nathanael, Uta Wille

JOURNAL OF ORGANIC CHEMISTRY | AMER CHEMICAL SOC | Published : 2019

Abstract

Kinetic and computational data reveal a complex behavior of the important environmental free radical oxidant NO3• in its reactions with aliphatic amino acids and di- and tripeptides, suggesting that attack at the amide N-H bond in the peptide backbone is a highly viable pathway, which proceeds through a proton-coupled electron transfer (PCET) mechanism with a rate coefficient of about 1 × 106 M-1 s-1 in acetonitrile. Similar rate coefficients were determined for hydrogen abstraction from the α-carbon and from tertiary C-H bonds in the side chain. The obtained rate coefficients for the reaction of NO3• with aliphatic di- and tripeptides suggest that attack occurs at all of these sites in each..

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Grants

Funding Acknowledgements

This work was supported by the Australian Research Council and The University of Melbourne. J.G.N. thanks the Australian Government for an Australian Government Research Training Program (RTP) Scholarship. Support of this work by Julius Kerstien is gratefully acknowledged. We thank Lars Goerigk, Craig Hutton, and Chris Easton for helpful discussions.