Horseradish peroxidase-catalyzed oxidation of chlorophyll a with hydrogen peroxide

2010

Horseradish peroxidase was verified to catalyze, without any phenol, the hydrogen peroxide oxidation of chlorophyll a (Chl a), solubilized with Triton X-100. The 13(2)(S) and 13(2)(R) diastereomers of 13(2)-hydroxyChl a were characterized as major oxidation products (ca. 60%) by TLC on sucrose, UV-vis, (1)H, and (13)C NMR spectra, as well as fast-atom bombardment MS. A minor amount of the 15(2)-methyl, 17(3)-phytyl ester of Mg-unstable chlorin was identified on the basis of its UV-vis spectrum and reactivity with diazomethane, which converted it to the 13(1),15(2)-dimethyl, 17(3)-phytyl ester of Mg-purpurin 7. The side products (ca. 10%) were suggested to include the 17(3)-phytyl ester of M…

Horseradish peroxidase-catalyzed oxidation of chlorophyll a with hydrogen peroxide Characterization of the products and mechanism of the reaction

AbstractHorseradish peroxidase was verified to catalyze, without any phenol, the hydrogen peroxide oxidation of chlorophyll a (Chl a), solubilized with Triton X-100. The 132(S) and 132(R) diastereomers of 132-hydroxyChl a were characterized as major oxidation products (ca. 60%) by TLC on sucrose, UV–vis, 1H, and 13C NMR spectra, as well as fast-atom bombardment MS. A minor amount of the 152-methyl, 173-phytyl ester of Mg-unstable chlorin was identified on the basis of its UV–vis spectrum and reactivity with diazomethane, which converted it to the 131,152-dimethyl, 173-phytyl ester of Mg-purpurin 7. The side products (ca. 10%) were suggested to include the 173-phytyl ester of Mg-purpurin 18,…