| Abstract | A Pseudomonas sp. grown on p-fluorophenylacetic acid is adapted to the metabolism of phenylacetic acid, 3-fluoro-3-hexenedioic acid, monofluorosuccinic acid, monofluorofumaric acid, β-ketoadipic acid, and β-hydroxyadipic acid. Cell suspensions catalyze the lactonization of 3-fluoro-3-hexenedioic acid to give 4-carboxymethyl-4-fluorobutanolide. The results suggest that 3-fluoro-3-hexenedioic acid is an intermediate in the degradation of p-fluorophenylacetic acid, and may be metabolized by two alternate pathways, depending on the lactone formed. 4-Carboxymethyl-4-fluorobutanolide may be hydrolyzed to give 3-hydroxy-3-fluoroadipic acid, which spontaneously eliminates hydrogen fluoride to give β-ketoadipic acid. Alternatively, 3-fluoro-3-hexenedioic acid may lactonize to form 4-carboxymethyl-3-fluorobutanolide, which is then hydrolyzed to 3-keto-4-fluoroadipic and cleaved to form acetate and monofluorosuccinic acid. The latter is converted to fluorofumaric acid by fumarase to give 2-fluoromalic acid. This unstable compound decomposes to oxaloacetate and hydrogen fluoride. The mechanism of ring cleavage and the mode of formation of 3-fluoro-3-hexenedioic acid are uncertain but may involve partial reduction of the aromatic ring before oxidative cleavage. |
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