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.
Department of Biochemistry, Universidade de São Paulo, Brazil.
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M
Villablanca
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G
Cilento
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