title: Studies on the Glutathione-Dependent Formaldehyde-Activating Enzyme from Paracoccus denitrificans.
abstract: Formaldehyde is a toxin and carcinogen that is both an environmental pollutant and an endogenous metabolite. Formaldehyde metabolism, which is probably essential for all aerobic cells, likely proceeds via multiple mechanisms, including via a glutathione-dependent pathway that is widely conserved in bacteria, plants and animals. However, it is unclear whether the first step in the glutathione-dependent pathway (i.e. formation of S-hydroxymethylglutathione (HMG)) is enzyme-catalysed. We report studies on glutathione-dependent formaldehyde-activating enzyme (GFA) from Paracoccus denitrificans, which has been proposed to catalyse HMG formation from glutathione and formaldehyde on the basis of studies using NMR exchange spectroscopy (EXSY). Although we were able to replicate the EXSY results, time course experiments unexpectedly imply that GFA does not catalyse HMG formation under standard conditions. However, GFA was observed to bind glutathione using NMR and mass spectrometry. Overall, the results reveal that GFA binds glutathione but does not directly catalyse HMG formation under standard conditions. Thus, it is possible that GFA acts as a glutathione carrier that acts to co-localise glutathione and formaldehyde in a cellular context.
authors.affiliation: Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford, United Kingdom.
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Hopkinson
authors.affiliation: Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford, United Kingdom.|School of Chemical Sciences, The University of Auckland, Auckland, New Zealand.
authors.forename: Ivanhoe K H
authors.initials: IK
authors.lastname: Leung
authors.affiliation: Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford, United Kingdom.
authors.forename: Tristan J
authors.initials: TJ
authors.lastname: Smart
authors.affiliation: Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford, United Kingdom.
authors.forename: Nathan R
authors.initials: NR
authors.lastname: Rose
authors.affiliation: Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford, United Kingdom.
authors.forename: Luc
authors.initials: L
authors.lastname: Henry
authors.affiliation: Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford, United Kingdom.
authors.forename: Timothy D W
authors.initials: TD
authors.lastname: Claridge
authors.affiliation: Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford, United Kingdom.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Schofield
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism; D019730:Carbon-Sulfur Ligases / Q000737:chemistry* / Q000378:metabolism; D005978:Glutathione / Q000031:analogs & derivatives / Q000378:metabolism; D008969:Molecular Sequence Data; D010231:Paracoccus denitrificans / Q000201:enzymology*
chemical_list: D001426:Bacterial Proteins; C029469:S-hydroxymethylglutathione; D019730:Carbon-Sulfur Ligases; C447825:glutathione-dependent formaldehyde-activating enzyme; D005978:Glutathione