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  • Publication
    Purification and properties of fluoroacetate dehalogenase from Pseudomonas fluorescens DSM 8341
    The degradation of fluoroacetate by microorganisms has been established for some time, although only a handful of dehalogenases capable of hydrolyzing the stable C-F bond have been studied. The bacterium Pseudomonas fluorescens DSM 8341 was originally isolated from soil and very readily degraded fluoroacetate, thus it was thought that its dehalogenase might have some desirable properties. The enzyme was purified from cell free extracts and characterised: it is a monomer of 32,500 Da, with a pH optimum of 8 and is stable between pH 4 and 10; its activity is stimulated by some metal ions (Mg2+, Mn2+ and Fe3+), but inhibited by others (Hg2+, Ag2+). The enzyme is specific for fluoroacetate, and the Km for this substrate (0.68 mM) is the lowest determined for enzymes of this type that have been investigated to date.
      1239Scopus© Citations 30
  • Publication
    Bacterial defluorination of 4-fluoroglutamic acid
    Fluorinated amino acids are used as enzyme inhibitors, mechanistic probes and in the production of pharmacologically active peptides. Because enantiomerically pure 4-fluoroglutamate is difficult to prepare, the selective degradation of the l-isomer is a potentially convenient method of obtaining d-4-fluoroglutamate from the racemate. In this paper, we describe our investigations on the degradation of 4-fluoroglutamate by bacteria. Fluoride ion was detected in resting-cell cultures of a number of bacteria that were incubated with racemic 4-fluoroglutamate. Analysis of the culture supernatants by chiral gas chromatography–mass spectrometry revealed that only the l-isomer was degraded. The degradation of 4-fluoroglutamate was also examined in cell-free extracts of Streptomyces cattleya and Proteus mirabilis, and it was observed that equimolar concentrations of fluoride ion and ammonia were generated. The activity was located in the soluble fraction of cell extracts, thus is not related to the l-2-amino-4-chloro-4-pentenoic acid dehydrochlorinase previously identified in membrane fractions of P. mirabilis.
      1290Scopus© Citations 5