title: Evaluation of models for the mechanism of action of 4-hydroxyphenylpyruvate dioxygenase.
abstract: 3-Hydroxyphenylpyruvic acid was oxygenated with various complexes of oxygen with Fe2+, superoxide ion, hydroperoxide anion, triplet and singlet oxygen. Oxidation occurred giving varying amounts of the 4-hydroxy derivatives of benzaldehyde, benzoic acid, phenol, phenylacetic acid and 4-carboxymethylquinone, but no homogentisic acid. 4-Hydroxyphenylperacetic acid was prepared and shown not to undergo self-oxidation. Its ferrous salt decomposed to 4-hydroxybenzyl alcohol. It is concluded that the alpha-keto carboxylic function is the site of oxygenation in the enzyme process and that a trioxalanone rather than a peracid intermediate may be implicated.
mesh_terms: D015111:4-Hydroxyphenylpyruvate Dioxygenase / Q000378:metabolism*; D007501:Iron; D008956:Models, Chemical; D010100:Oxygen; D010105:Oxygenases / Q000378:metabolism*
chemical_list: D007501:Iron; D010105:Oxygenases; D015111:4-Hydroxyphenylpyruvate Dioxygenase; D010100:Oxygen