Oxidation of phenylpyruvic acid.
Mn2+ catalyzes the aerobic oxidation of phenylpyruvic acid. Benzaldehyde and oxalate are the major products, the former being generated to some extent in an excited state, as indicated by chlorophyll-sensitized emission. Both oxygen consumption and emission are enhanced by addition of horseradish peroxidase. In the presence of the enzyme, halogen-containing xanthene dyes also sensitize the emission. From the values of the benzaldehyde/oxalate product ratio, it is inferred that two oxidation pathways are operative. One of these proceeds via a dioxetane intermediate and is responsible for the excited benzaldehyde; the other, which involves an alpha-keto-beta-peroxylactone, does not produce oxalate. The enzyme appears to favour the dioxetane route. The relative importance of these routes in biological systems is discussed.
Villablanca
M
M
Department of Biochemistry, Universidade de São Paulo, Brazil.
Cilento
G
G
D001547:Benzaldehydes / Q000378:metabolism; D003300:Copper / Q000378:metabolism; D005290:Ferric Compounds / Q000378:metabolism; D006735:Horseradish Peroxidase / Q000378:metabolism; D008345:Manganese / Q000378:metabolism; D010070:Oxalates / Q000378:metabolism; D019815:Oxalic Acid; D010084:Oxidation-Reduction; D010101:Oxygen Consumption; D010667:Phenylpyruvic Acids / Q000378:metabolism*; D013997:Time Factors
D001547:Benzaldehydes; D005290:Ferric Compounds; D010070:Oxalates; D010667:Phenylpyruvic Acids; D008345:Manganese; D003300:Copper; D019815:Oxalic Acid; D006735:Horseradish Peroxidase; C032175:benzaldehyde; C031606:phenylpyruvic acid