ArticleThe Biochemical journal1992
Participation of the phenolic hydroxyl group of Tyr-8 in the catalytic mechanism of human glutathione transferase P1-1.
Article in The Biochemical journal, 1992. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 22 papers.
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Who cites it
22 citing papers in PubMed, 85 citations in OpenAlex.
- Human GST P1-1 Redesigned for Enhanced Catalytic Activity with the Anticancer Prodrug Telcyta and Improved Thermostability.Cancers · 2024Article
- Profiling the Site of Protein CoAlation and Coenzyme A Stabilization Interactions.Antioxidants (Basel, Switzerland) · 2022Article
- Characterization of Dog Glutathione Transferase P1-1, an Enzyme Relevant to Veterinary Medicine.International journal of molecular sciences · 2021Article
- Catalysis of Silver catfish Major Hepatic Glutathione Transferase proceeds via rapid equilibrium sequential random Mechanism.Toxicology reports · 2016Article
- A novel method for screening the glutathione transferase inhibitors.BMC biochemistry · 2009Article
- A functionally conserved basic residue in glutathione transferases interacts with the glycine moiety of glutathione and is pivotal for enzyme catalysis.The Biochemical journal · 2007Article
- Plasmodium falciparum glutathione S-transferase--structural and mechanistic studies on ligand binding and enzyme inhibition.Protein science : a publication of the Protein Society · 2006Article
- Proton release on binding of glutathione to alpha, Mu and Delta class glutathione transferases.The Biochemical journal · 1999Article
- The role of tyrosine-9 and the C-terminal helix in the catalytic mechanism of Alpha-class glutathione S-transferases.The Biochemical journal · 1999Article
- The three-dimensional structure of a class-Pi glutathione S-transferase complexed with glutathione: the active-site hydration provides insights into the reaction mechanism.The Biochemical journal · 1998Article
- Pressure-dependent ionization of Tyr 9 in glutathione S-transferase A1-1: contribution of the C-terminal helix to a "soft" active site.Protein science : a publication of the Protein Society · 1997Article
- Mutagenesis of the active site of the human Theta-class glutathione transferase GSTT2-2: catalysis with different substrates involves different residues.The Biochemical journal · 1996Article
- Tyrosine 8 contributes to catalysis but is not required for activity of rat liver glutathione S-transferase, 1-1.Protein science : a publication of the Protein Society · 1996Article
- Glutathione S-transferase and S-crystallins of cephalopods: evolution from active enzyme to lens-refractive proteins.Journal of molecular evolution · 1995Article
- Isothiocyanates as substrates for human glutathione transferases: structure-activity studies.The Biochemical journal · 1995Article
- Steady-state kinetics and chemical mechanism of octopus hepatopancreatic glutathione transferase.The Biochemical journal · 1995Article
- Crystal structure of a theta-class glutathione transferase.The EMBO journal · 1995Article
- Photoaffinity labelling of the active site of the rat glutathione transferases 3-3 and 1-1 and human glutathione transferase A1-1.The Biochemical journal · 1994Article
- Detoxication of base propenals and other alpha, beta-unsaturated aldehyde products of radical reactions and lipid peroxidation by human glutathione transferases.Proceedings of the National Academy of Sciences of the United States of America · 1994Article
- Co-variation of glutathione transferase expression and cytostatic drug resistance in HeLa cells: establishment of class Mu glutathione transferase M3-3 as the dominating isoenzyme.The Biochemical journal · 1994Article
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3 authors at 1 institution in 1 country.
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Abstract
The coding region of cDNA corresponding to human class Pi glutathione transferase P1-1 was amplified by the PCR, subcloned into an expression vector, pKHP1, expressed in Escherichia coli, and characterized. The physicochemical and catalytic properties of recombinant glutathione transferase P1-1 were indistinguishable from those of the enzyme previously isolated from human placenta. The active-site residue Tyr-8 of the wild-type enzyme was converted into Phe by means of oligonucleotide-directed mutagenesis. The mutant enzyme Y8F displayed a 300-fold decrease in specific activity, ascribable mainly to a lowered k(cat.) (or V) value. Kinetic parameters reflecting binding affinity, S0.5 (substrate concn. giving 1/2V) and I50 (concn. of inhibitor giving 50% remaining activity), were only moderately elevated in the mutant enzyme. These results indicate that Tyr-8 contributes primarily to catalysis as such, rather than to binding of the substrates. The dependence of k(cat.)/Km on pH shows an optimum at pH 7.0, defined by acidic and basic ionic dissociation constants with pKa1 = 6.7 and pKa2 = 7.3 respectively. The mutant enzyme Y8F does not display the basic limb of the k(cat.)/Km versus pH profile, but shows a monotonic increase of k(cat.)/Km with an apparent pKa1 of 7.1. The results indicate that the phenolic hydroxyl group of Tyr-8 in un-ionized form, but not the phenolate of Tyr-8, contributes to catalysis by glutathione transferase P1-1.
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