e.g. Salicylate 0 catechol + CO2
Pseudomonas putida enzyme is a monomer, molecular weight 54000. The amino acid composition and the terminal amino acids have been determined [A1216]. Another study using a different strain found a molecular weight of 45 000, with a different amino acid composition [F658]. The reaction requires oxygen and NADH, with carbon dioxide as the second product. Salicylaldehyde is also a substrate, and this releases formate [B751]. By using specifically ring-labelled salicylate it has been found that decarboxylation and hydroxylation with P. cepacia enzyme occur at the same carbon atom [B883]. It is an inducible enzyme [E287]. A Pseudomonas enzyme also acts on 3- and 5-chlorosalicylate and 3,5-dichlorosalicylate [H506].
Trichosporon cutaneum enzyme, molecular weight 45 300 and optimum pH 7.5, contains FAD. It also acts on salicylates substituted with a hydroxyl group at positions 3, 4, 5 and 6, an amino or chloro group at 4 or 5, a methyl at 4, or a methoxy or fluoro at 5 [D232].
This reaction has been found to occur non-enzymatically in rat, catalysed by free radicals formed by the parkinsonism-inducing ion MPP + [J681]. In rat liver the formation of catechol and other products from salicylate is catalysed by the action of hydroxyl free radicals rather than by the direct action of a decarboxylating hydroxylase [J754].
Trichosporon cutaneum acts on gentisate to form hydroxyquinol [B368].
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