Reaction of Amino Acids, Di- and Tripeptides with the Environmental Oxidant NO3 .: A Laser Flash Photolysis and Computational Study

Abstract

Absolute rate coefficients for the reaction between the important environmental free radical oxidant NO3 . and a series of N- and C-protected amino acids, di- and tripeptides were determined using 355 nm laser flash photolysis of cerium(IV) ammonium nitrate in the presence of the respective substrates in acetonitrile at 298±1 K. Through combination with computational studies it was revealed that the reaction with acyclic aliphatic amino acids proceeds through hydrogen abstraction from the α-carbon, which is associated with a rate coefficient of about 1.8×106 m−1 s−1 per abstractable hydrogen atom. The considerably faster reaction with phenylalanine [k=(1.1±0.1)×107 m−1 s−1] is indicative for..