Photochemical and thermal reactivity of kynurenine

The thermal and photochemical reactivity of kynurenine (KN), a tryptophan metabolite found in human lenses, has been studied in aqueous solution. The decarboxylation reaction of KN, resulting in the formation of 4-hydroxyquinoline, is reported for the first time. Rate constants for KN deamination and decarboxylation were determined in the temperature range 50-90 degrees C. The quantum yields for KN photodecomposition under argon were measured to be Phi(Ar) = (2.0 +/- 0.2) x 10(-5) and under oxygen (DO2 = (1-1 +/- 0.1) X 10(-4). (c) 2006 Elsevier Ltd. All rights reserved.