title: A novel glutathione transferase from Haemophilus influenzae which has high affinity towards antibiotics.
abstract: Cytosolic glutathione transferase (GSTs) are a family of multi-functional proteins which catalyse the conjugation of glutathione (GSH) to a large variety of endogenous and exogenous electrophilic compounds. Much is known about cytosolic mammalian GSTs, however, the presence of GSTs in several aerobic and anaerobic micro-organisms has also been demonstrated. Several findings seem to suggest that bacterial GSTs are involved in processes of biodegradation of xenobiotics, including antibiotics. However, the function played by these enzymes in the bacterial cell still remains to be clarified. At present, it is ill-defined whether bacterial GST can be classified, as in the case of mammalian enzymes, into several distinct classes. Here we report the purification of a GST isoform from Haemophilus influenzae using GSH-affinity chromatography. The purified protein was characterised by immunological and kinetic properties different from other known GSTs. The dissociation constants of chloramphenicol, ampicillin, rifampicin and tetracycline to the purified enzyme were 0.62, 9.06, 4.08 and 1.77 microM, respectively, as determined by following the quenching of the protein intrinsic fluorescence. These values were much lower than those previously determined for the same drugs with other mammalian or bacterial GSTs. The present results indicate that the enzyme purified from H. influenzae is a novel GST isoform well distinguished from other known mammalian or bacterial GSTs.
authors: Dipartimento di Scienze del Farmaco, Universita' G. D'Annunzio, Chieti, Italy.
authors: Benedetto
authors: B
authors: Dainelli
authors: Domenico
authors: D
authors: Paludi
authors: Beatrice
authors: B
authors: Dragani
authors: Roberta
authors: R
authors: Cocco
authors: Daniela Rossi
authors: DR
authors: Principe
authors: Massimiliano
authors: M
authors: Petrucci
authors: Felice
authors: F
authors: Mucilli
authors: Angelo
authors: A
authors: Faraone
authors: Antonio
authors: A
authors: Aceto
mesh_terms: D000667:Ampicillin / Q000378:metabolism*; D000900:Anti-Bacterial Agents / Q000378:metabolism*; D002701:Chloramphenicol / Q000378:metabolism*; D005982:Glutathione Transferase / Q000276:immunology / Q000378:metabolism*; D006193:Haemophilus influenzae / Q000201:enzymology*; D006801:Humans; D007527:Isoenzymes / Q000276:immunology / Q000378:metabolism; D007700:Kinetics; D011485:Protein Binding; D012293:Rifampin / Q000378:metabolism*; D013752:Tetracycline / Q000378:metabolism*
chemical_list: D000900:Anti-Bacterial Agents; D007527:Isoenzymes; D002701:Chloramphenicol; D000667:Ampicillin; D005982:Glutathione Transferase; D013752:Tetracycline; D012293:Rifampin