Evolution of differential substrate specificities in Mu class glutathione transferases probed by DNA shuffling 1 1Edited by R. Huber

1999 ◽  
Vol 287 (2) ◽  
pp. 265-276 ◽  
Author(s):  
Lars O Hansson ◽  
Robyn Bolton-Grob ◽  
Tahereh Massoud ◽  
Bengt Mannervik
Keyword(s):  
Glutathione Transferases ◽  
Dna Shuffling ◽  
Substrate Specificities

scholarly journals Novel class of glutathione transferases from cyanobacteria exhibit high catalytic activities towards naturally occurring isothiocyanates

2007 ◽  
Vol 406 (1) ◽  
pp. 115-123 ◽  
Author(s):  
Eric Wiktelius ◽  
Gun Stenberg
Keyword(s):  
Catalytic Properties ◽  
Structural Features ◽  
Glutathione Transferases ◽  
Substrate Specificities ◽  
Catalytic Activities ◽  
Genome Databases ◽  
Naturally Occurring ◽  
Physiological Relevance ◽  
Associated Proteins

In the present paper, we report a novel class of GSTs (glutathione transferases), called the Chi class, originating from cyanobacteria and with properties not observed previously in prokaryotic enzymes. GSTs constitute a widespread multifunctional group of proteins, of which mammalian enzymes are the best characterized. Although GSTs have their origin in prokaryotes, few bacterial representatives have been characterized in detail, and the catalytic activities and substrate specificities observed have generally been very modest. The few well-studied bacterial GSTs have largely unknown physiological functions. Genome databases reveal that cyanobacteria have an extensive arsenal of glutathione-associated proteins. We have studied two cyanobacterial GSTs which are the first examples of bacterial enzymes that are as catalytically efficient as the best mammalian enzymes. GSTs from the thermophile Thermosynechococcus elongatus BP-1 and from Synechococcus elongatus PCC 6301 were found to catalyse the conjugation of naturally occurring plant-derived isothiocyanates to glutathione at high rates. The cyanobacterial GSTs studied are smaller than previously described members of this enzyme family, but display many of the typical structural features that are characteristics of GSTs. They are also active towards several classical substrates, but at the same moderate rates that have been observed for other GSTs derived from prokaryotes. The cloning, expression and characterization of two cyanobacterial GSTs are described. The possible significance of the observed catalytic properties is discussed in the context of physiological relevance and GST evolution.

scholarly journals Isoenzymes of glutathione transferase in rat kidney cytosol

1985 ◽  
Vol 230 (3) ◽  
pp. 609-615 ◽  
Author(s):  
C Guthenberg ◽  
H Jensson ◽  
L Nyström ◽  
E Österlund ◽  
M K Tahir ◽  
...  
Keyword(s):  
Rat Liver ◽  
Liver Enzymes ◽  
Glutathione Transferase ◽  
Ethacrynic Acid ◽  
Rat Kidney ◽  
Glutathione Transferases ◽  
Substrate Specificities ◽  
Additional Peak ◽  
Rat Kidney Cytosol ◽  
Rat Liver Cytosol

Glutathione transferases from rat kidney cytosol were purified about 40-fold by chromatography on S-hexylglutathione linked to epoxy-activated Sepharose 6B. Further purification by fast protein liquid chromatography with chromatofocusing in the pH interval 10.6-7.6 resolved five major peaks of activity with 1-chloro-2,4-dinitrobenzene as the second substrate. Four of the peaks were identified with rat liver transferases 1-1, 1-2, 2-2 and 4-4 respectively. The criteria used for identification included physical properties, reactions with specific antibodies, substrate specificities and sensitivities to several inhibitors. The fourth major peak is a ‘new’ form of transferase, which has not been found in rat liver. This isoenzyme, glutathione transferase 7-7, has a lower apparent subunit Mr than any of the transferases isolated from rat liver cytosol, and does not react with antibodies raised against the liver enzymes. Glutathione transferases 3-3 and 3-4, which are abundant in liver, were only present in very small amounts. In a separate chromatofocusing separation in a lower pH interval, an additional peak was eluted at pH 6.3. This isoenzyme is characterized by its high activity with ethacrynic acid.

scholarly journals Characterization of Affinity-Purified Isoforms ofAcinetobacter calcoaceticusY1 Glutathione Transferases

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Chin-Soon Chee ◽  
Irene Kit-Ping Tan ◽  
Zazali Alias
Keyword(s):  
Hydrogen Peroxide ◽  
Molecular Weight ◽  
Gel Electrophoresis ◽  
Ethacrynic Acid ◽  
Polyacrylamide Gel Electrophoresis ◽  
Acinetobacter Calcoaceticus ◽  
Glutathione Transferases ◽  
Glutathione S Transferase ◽  
Substrate Specificities

Glutathione transferases (GST) were purified from locally isolated bacteria,Acinetobacter calcoaceticusY1, by glutathione-affinity chromatography and anion exchange, and their substrate specificities were investigated. SDS-polyacrylamide gel electrophoresis revealed that the purified GST resolved into a single band with a molecular weight (MW) of 23 kDa. 2-dimensional (2-D) gel electrophoresis showed the presence of two isoforms, GST1 (pI 4.5) and GST2 (pI 6.2) with identical MW. GST1 was reactive towards ethacrynic acid, hydrogen peroxide, 1-chloro-2,4-dinitrobenzene, andtrans,trans-hepta-2,4-dienalwhile GST2 was active towards all substrates except hydrogen peroxide. This demonstrated that GST1 possessed peroxidase activity which was absent in GST2. This study also showed that only GST2 was able to conjugate GSH to isoproturon, a herbicide. GST1 and GST2 were suggested to be similar to F0KLY9 (putative glutathione S-transferase) and F0KKB0 (glutathione S-transferase III) ofAcinetobacter calcoaceticusstrain PHEA-2, respectively.

Directed evolution of Tau class glutathione transferases reveals a site that regulates catalytic efficiency and masks co-operativity

2016 ◽  
Vol 473 (5) ◽  
pp. 559-570 ◽  
Author(s):  
Irine Axarli ◽  
Abdi W. Muleta ◽  
Dimitrios Vlachakis ◽  
Sophia Kossida ◽  
Georgia Kotzia ◽  
...  
Keyword(s):  
Directed Evolution ◽  
Catalytic Efficiency ◽  
Glutathione Transferases ◽  
Dna Shuffling ◽  
A Site ◽  
Metabolism Of Xenobiotics

GSTs (glutathione transferases) are enzymes involved in the metabolism of xenobiotics. A GST created through DNA shuffling showed allosteric kinetics and enhanced detoxifying potential towards the herbicide fluorodifen. Its structure was determined. New engineered GSTs could be useful in biotechnology as efficient bioscavengers.

scholarly journals Isoenzymes of glutathione transferase in rat small intestine

1988 ◽  
Vol 253 (3) ◽  
pp. 759-764 ◽  
Author(s):  
M K Tahir ◽  
N Ozer ◽  
B Mannervik
Keyword(s):  
Small Intestine ◽  
Glutathione Transferase ◽  
Double Diffusion ◽  
Glutathione Transferases ◽  
Variant Form ◽  
Rat Small Intestine ◽  
Substrate Specificities ◽  
Specific Antibodies ◽  
Diffusion Analysis ◽  
Isoelectric Points

The major glutathione transferases in the rat small-intestine cytosol were isolated and characterized. The enzymes active with 1-chloro-2,4-dinitrobenzene as second substrate were almost quantitatively recovered after affinity chromatography on immobilized S-hexylglutathione. The different basic forms of glutathione transferase, which account for 90% of the activity, were resolved by chromatofocusing. Fractions containing enzymes with lower isoelectric points were not further resolved. The isolated fractions were characterized by their elution position in chromatofocusing, apparent subunit Mr, reactions with specific antibodies, substrate specificities and inhibition characteristics. The major basic forms identified were glutathione transferases 1-1, 4-4 and 7-7. In addition, evidence for the presence of a variant form of subunit 1, as well as trace amounts of subunits 2 and 3, was obtained. A significant amount of transferase 8-8 in the fraction of acidic enzyme forms was demonstrated by immunoblot and Ouchterlony double-diffusion analysis. In the comparison of the occurrence of the different forms of glutathione transferase in liver, lung, kidney and small intestine, it was found that the small intestine is the richest source of glutathione transferase 7-7.

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