RESUMO
1. Halogen analogues of benzoate and p-nitrobenzoate did not support growth of Nocardia erythropolis. 2. These analogues, when present together with the parent compounds, inhibited growth of the organism. 3. The halogen analogues similarly inhibited oxidation of benzoate or p-nitrobenzoate by competent cells. 4. Fluoroacetate and 2-fluoro-4-nitrobenzoate caused comparable inhibition of growth on p-nitrobenzoate and both led to some citrate accumulation. 5. The induction of the p-nitrobenzoate-oxidation system was strongly inhibited by all the 2-halogeno-4-nitrobenzoates although the 2-fluoro and 2-chloro derivatives also acted as inducers. 6. Halogen analogues of benzoate also induced the benzoate-oxidation system.
Assuntos
Benzoatos/farmacologia , Indução Enzimática/efeitos dos fármacos , Halogênios/farmacologia , Nocardia/efeitos dos fármacos , Consumo de Oxigênio/efeitos dos fármacos , Benzoatos/metabolismo , Cloro/farmacologia , Citratos/metabolismo , Densitometria , Depressão Química , Flúor/farmacologia , Fluoracetatos/farmacologia , Liofilização , Genética Microbiana , Manometria , Nitrobenzenos/farmacologia , Nocardia/enzimologia , Nocardia/crescimento & desenvolvimento , Nocardia/metabolismoRESUMO
1. Halogen analogues of p-nitrobenzoate and benzoate were oxidized by washed cells of Nocardia erythropolis. 2. The oxidation of 2-fluoro-4-nitrobenzoate ceased at the level of acetate, and fluoroacetate was found in the incubation medium and particularly in hot-ethanolic extracts of the cells. 3. Several fluorine-containing intermediates were detected and 2-fluoroprotocatechuate was identified as one of them. 4. The nitro group was also reduced by the organism, as evidenced by the formation of 4-amino-2-fluorobenzoate. 5. Extracts of N. erythropolis activated fluoroacetate and condensed the resulting fluoroacetyl-CoA with oxaloacetate to form fluorocitrate. This product was a very powerful inhibitor of citrate metabolism by guinea-pig kidney homogenates and of the aconitase also present in the bacterial extracts. The inhibitions effected by synthetic fluorocitrate and the natural product were comparable. 6. 2-Fluoro-4-nitrobenzoate had negligible mammalian toxicity. 7. The isolation of fluoroacetate as a product of 2-fluoro-4-nitrobenzoate oxidation implies that the aromatic ring in this bacterium must be degraded via a gamma-carboxymuconolactone; fluoroacetate cannot arise by metabolism through the isomeric beta-carboxymuconolactone.