Abeer Shokeer, Anna-Karin Larsson, Bengt Mannervik
Index: Biochem. J. 388(Pt 1) , 387-92, (2005)
Full Text: HTML
GST (glutathione transferase) T1-1 plays an important role in the biotransformation of halogenated alkanes, which are used in large quantities as solvents and occur as environmental pollutants. Many reactions that are catalysed by GST T1-1 qualify as detoxification processes, but some reactions with dihalogenated alkanes lead to reactive products more toxic than the substrates. Murine GST T1-1 is particularly active with dichloromethane, which may explain the high carcinogenicity of dichloromethane in the mouse. Human GST T1-1 activity is considerably lower with halogenated hydrocarbons and some related substrates. Human GST T1-1 is polymorphic with a frequent null phenotype, suggesting that it is advantageous, under some circumstances, to lack the functional enzyme, which catalyses GSH conjugations that may cause bioactivation. The present study shows that amino acid residue 234 is a determinant of the differences in catalytic efficiency between the human and the rodent enzymes. The replacement of Trp234 in human GST T1-1 by arginine, found in the rodent enzyme, enhanced the alkyltransferase activity by an order of magnitude with a series of homologous iodoalkanes and some typical GST substrates. The specific activity of the alternative mutant Trp234-->Lys was lower than for the parental human GST T1-1 with many substrates, showing that a positive charge is not sufficient for increased activity. The enhanced activity of Trp234-->Arg with alkylating agents was dependent on the substrate tested, whereas no increase of the peroxidase activity with cumene hydroperoxide was noted. Residue 234 therefore is also involved in the control of the substrate selectivity of GST T1-1.
Structure | Name/CAS No. | Molecular Formula | Articles |
---|---|---|---|
![]() |
1-(2-Bromoethyl)-4-nitrobenzene
CAS:5339-26-4 |
C8H8BrNO2 |
An ensemble of theta class glutathione transferases with nov...
2002-04-19 [J. Mol. Biol. 318(1) , 59-70, (2002)] |
A glutathione S-transferase (GST) isozyme from broccoli with...
1994-03-16 [Biochim. Biophys. Acta 1205(1) , 29-38, (1994)] |
Kinetic characterization of recombinant human glutathione tr...
1997-12-15 [Arch. Biochem. Biophys. 348(2) , 247-54, (1997)] |
Enzymatic inactivation of major circulating forms of atrial ...
1999-04-16 [Eur. J. Pharmacol. 370(3) , 307-12, (1999)] |
Molecular evolution of Theta-class glutathione transferase f...
2010-05-01 [Arch. Biochem. Biophys. 497(1-2) , 28-34, (2010)] |
Home | MSDS/SDS Database Search | Journals | Product Classification | Biologically Active Compounds | Selling Leads | About Us | Disclaimer
Copyright © 2024 ChemSrc All Rights Reserved