The specificity of oxidase and kinase preparations from Pseudomonas fluorescens towards deoxyfluoromonosaccharides

With partially purified enzyme preparations from cell-free extracts of Pseudomonas fluorescens, 3-deoxy-3-fluoro-D-glucose and 3-deoxy-3-fluoro-D-gluconic acid are substrates for glucose oxidase (EC 1.1.3.4.) and gluconate dehydrogenase (EC 1.1.99.3), with K-m values 18.2 mM and 11.8 mM, respectively. The same enzymes that oxidize glucose and gluconic acid probably oxidize 3-deoxy-3-fluoro-D-glucose and 3-deoxy-3-fluoro-D-gluconic acid. The latter fluorinated carbohydrates and the presumed formation of 3-deoxy-3-fluoro-2-keto-D-gluconic acid, which has been isolated as a calcium salt and characterizied, are not substrates for gluconokinase (EC 2.7.1.12). Both 3-deoxy-3-fluoro-D-glucose and 3-deoxy-3-fluoro-D-gluconic acid act as competitive inhibitors of this enzyme preparation for gluconate, with K-i values 47.5 mM and 14.8 mM, respectively.