scholarly journals Ethoxyquin-induced resistance to aflatoxin B1 in the rat is associated with the expression of a novel Alpha-class glutathione S-transferase subunit, Yc2, which possesses high catalytic activity for aflatoxin B1-8,9-epoxide

1991 ◽  
Vol 279 (2) ◽  
pp. 385-398 ◽  
Author(s):  
J D Hayes ◽  
D J Judah ◽  
L I McLellan ◽  
L A Kerr ◽  
S D Peacock ◽  
...  
Keyword(s):  
Aflatoxin B1 ◽  
Neonatal Rat ◽  
High Catalytic Activity ◽  
Amino Acid Sequencing ◽  
Glutathione S Transferase ◽  
Adult Rats ◽  
Purification Scheme ◽  
Glutathione S Transferases ◽  
A Subunit ◽  
Rat Livers

A purification scheme has been devised for two ethoxyquin-inducible Alpha-class glutathione S-transferases (GSTs) which possess at least 25-fold greater activity towards aflatoxin B1 (AFB1)-8,9-epoxide than that exhibited by the GSTs (i.e. F, L, B and AA) that have been described previously. These two enzymes are both heterodimers and both contain a subunit of Mr 25,800. This subunit has been isolated from both of the GST isoenzymes and, after cleavage with CNBr, it has been subjected to automated amino acid sequencing. The primary structure of the Mr 25,800 subunit revealed that it forms part of a subfamily of Alpha-class GSTs which possess closest identity (about 92%) with the Yc subunit of apparent Mr 27,500, which is encoded by the recombinant cDNA clone pGTB42 [Telakowski-Hopkins, Rodkey, Bennett, Lu & Pickett (1985) J. Biol. Chem. 260, 5820-5825]. As these two GSTs possess less than 70% sequence identity with the Ya1 and Ya2 subunits, both of Mr 25,500, the constitutively expressed Yc subunit of Mr 27,500 has been renamed Yc1 and the ethoxyquin-inducible GST of Mr 25,800 has been designated Yc2. Using this nomenclature, the two GSTs with high activity for AFB1-8,9-epoxide are Ya1Yc2 and Yc1Yc2. Although evidence suggests that induction of Yc2 is responsible for the high detoxification capacity of livers from ethoxyquin-treated rats for AFB1-8,9-epoxide, resistance towards AFB1 may be multifactorial in this instance as dietary ethoxyquin also induces the Ya1, Ya2 and Yc1 subunits about 2.2-, 10.9- and 2.7-fold respectively. Besides the induction of GST by ethoxyquin, activity towards AFB1-8,9-epoxide is also elevated in the livers of neonatal rats and in livers that contain preneoplastic nodules. Western blotting experiments show that Yc2 is not present in hepatic cytosol from adult rats fed on normal diets but is expressed in neonatal rat livers and in the livers of adult rats that contain preneoplastic nodules that have arisen as a consequence of consuming diets contaminated with AFB1.

scholarly journals Cloning and expression of a chick liver glutathione S-transferase CL 3 subunit with the use of a baculovirus expression system

1992 ◽  
Vol 281 (2) ◽  
pp. 545-551 ◽  
Author(s):  
L H Chang ◽  
J Y Fan ◽  
L F Liu ◽  
S P Tsai ◽  
M F Tam
Keyword(s):  
Specific Activity ◽  
Sequence Similarity ◽  
Expression System ◽  
Baculovirus Expression System ◽  
Relative Activity ◽  
Cloning And Expression ◽  
Glutathione S Transferase ◽  
Sds Page ◽  
Glutathione S Transferases ◽  
A Subunit

Glutathione S-transferase CL 3 subunits purified from 1-day-old-chick livers were digested with Achromobacter proteinase I and the resulting fragments were isolated for amino acid sequence analysis. An oligonucleotide probe was constructed accordingly for cDNA library screening. A cDNA clone of 1342 bases, pGCL301, encoding a protein of 26209 Da was isolated and sequenced. Including conservative substitutions, this protein has 75-79% sequence similarity to other Alpha family glutathione S-transferases. The coding sequence of pGCL301 was inserted into a baculovirus vector for infection of Spodoptera frugiperda (SF9) cells. The expressed protein has a high relative activity with ethacrynic acid (47% of the specific activity with 1-chloro-2,4-dinitrobenzene). The enzyme has a subunit molecular mass of 25.2 +/- 1.2 kDa (by SDS/PAGE), a pI of 9.45 and an absorption coefficient A1%1cm of 13.0 +/- 0.5 at 280 nm.

scholarly journals Glutathione S-transferases from the white-rot fungus, Phanerochaete chrysosporium

1997 ◽  
Vol 324 (1) ◽  
pp. 243-248 ◽  
Author(s):  
Caitriona A. DOWD ◽  
Catherine M. BUCKLEY ◽  
David SHEEHAN
Keyword(s):  
Molecular Mass ◽  
Phanerochaete Chrysosporium ◽  
Sequence Similarity ◽  
Gel Filtration ◽  
Preliminary Evidence ◽  
White Rot ◽  
White Rot Fungus ◽  
Glutathione S Transferase ◽  
Glutathione S Transferases ◽  
A Subunit

A glutathione S-transferase (GST) was purified to homogeneity from the white-rot fungus, Phanerochaete chrysosporium, by affinity chromatography on glutathione–agarose followed by Mono-Q ion-exchange FPLC. This protein immunoblotted with antisera to rat Theta class GST 5-5 and also showed N-terminal sequence similarity to the Theta class, including the presence of a conserved serine residue that has been specifically implicated in catalysis in this class [Wilce, Board, Feil and Parker (1995) EMBO J. 14, 2133–2143] and other residues conserved in plant sequences. Catalytic activity was found to be highly labile in the purified protein, although preliminary evidence for activity (approx. 120 m-units/mg) with 1,2-epoxy-3-(p-nitrophenoxy)propane was obtained in some preparations. The enzyme seems to be a dimer with a subunit molecular mass of 25 kDa by SDS/PAGE. The native molecular masses estimated by non-denaturing electrophoresis and by Superose-12 gel filtration were 58 and 45 kDa respectively. A second protein purified in this study also gave low level of activity with 1,2-epoxy-3-(p-nitrophenoxy)propane and had a subunit molecular mass of 28 kDa (native size 62–63 kDa), but did not immunoblot with any GST class and seemed to be N-terminally blocked.

scholarly journals Molecular cloning and heterologous expression of a cDNA encoding a mouse glutathione S-transferase Yc subunit possessing high catalytic activity for aflatoxin B1-8,9-epoxide

1992 ◽  
Vol 285 (1) ◽  
pp. 173-180 ◽  
Author(s):  
J D Hayes ◽  
D J Judah ◽  
G E Neal ◽  
T Nguyen
Keyword(s):  
Catalytic Activity ◽  
Amino Acid ◽  
Amino Acid Sequence ◽  
Rat Liver ◽  
Cdna Clone ◽  
Aflatoxin B1 ◽  
Mouse Liver ◽  
High Catalytic Activity ◽  
Glutathione S Transferase ◽  
E Coli

Resistance to the carcinogenic effects of aflatoxin B1 (AFB1) in the mouse is due to the constitutive expression of an Alpha-class glutathione S-transferase (GST), YcYc, with high detoxification activity towards AFB1-8,9-epoxide. A cDNA clone (pmusGST Yc) for a murine GST Yc polypeptide has been isolated. Sequencing has shown the cDNA insert of pmusGST Yc to be 922 bp in length, with an open reading frame of 663 bp that encodes a polypeptide of M(r) 25358. The primary structure of the murine GST Yc subunit predicted by pmusGST Yc is in complete agreement with the partial amino acid sequence of the aflatoxin-metabolizing mouse liver GST described previously [McLellan, Kerr, Cronshaw & Hayes (1991) Biochem. J. 276, 461-469]. A plasmid, termed pKK-musGST Yc, which permits the expression of the murine Yc subunit in Escherichia coli, has been constructed. The murine GST expressed in E. coli was purified and found to be catalytically active towards several GST substrates, including AFB1-8,9-epoxide. This enzyme was also found to possess electrophoretic and immunochemical properties closely similar to those of the GST Yc subunit from mouse liver. However, the GST synthesized in E. coli and the constitutive mouse liver Alpha-class GST exhibited small differences in their chromatographic behaviour during reverse-phase h.p.l.c. Automated Edman degradation revealed alanine to be the N-terminal amino acid in the GST Yc subunit expressed in E. coli, whereas the enzyme in mouse liver possesses a blocked N-terminus. Although sequencing showed that the purified Yc subunit from E. coli lacked the initiator methionine, the amino acid sequence obtained over the first eleven N-terminal residues agreed with that predicted from the cDNA clone, pmusGST Yc. Comparison of the deduced amino acid sequence of the mouse Yc polypeptide with the primary structures of the rat Alpha-class GST enzymes revealed that it is more closely related to the ethoxyquin-induced rat liver Yc2 subunit than to the constitutively expressed rat liver Yc1 subunit. The significance of the fact that both mouse Yc and rat Yc2 exhibit high catalytic activity towards AFB1-8,9-epoxide, whereas rat Yc1 possesses little activity towards this compound, is discussed in terms of structure/function.

Glutathione S-transferase localization in aflatoxin B1-treated rat livers

1990 ◽  
Vol 11 (6) ◽  
pp. 927-931 ◽  
Author(s):  
David J. Harrison ◽  
Linda May ◽  
John D. Hayes ◽  
Gordon E. Neal
Keyword(s):  
Aflatoxin B1 ◽  
Glutathione S Transferase ◽  
Rat Livers

scholarly journals Preferential over-expression of the class alpha rat Ya2 glutathione S-transferase subunit in livers bearing aflatoxin-induced pre-neoplastic nodules. Comparison of the primary structures of Ya1 and Ya2 with cloned class alpha glutathione S-transferase cDNA sequences

1990 ◽  
Vol 268 (2) ◽  
pp. 295-302 ◽  
Author(s):  
J D Hayes ◽  
L A Kerr ◽  
D J Harrison ◽  
A D Cronshaw ◽  
A G Ross ◽  
...  
Keyword(s):  
Amino Acid ◽  
Aflatoxin B1 ◽  
Acquired Resistance ◽  
Amino Acid Sequences ◽  
Glutathione S Transferase ◽  
Over Expression ◽  
Cdna Sequences ◽  
Normal Rat ◽  
Primary Structures ◽  
Rat Livers

Normal rat liver expresses Ya (Mr 25,500), Yc (Mr 27,500) and Yk (Mr 25,000) Class Alpha glutathione S-transferase (GST) subunits. The Ya-type subunit can be resolved into two separate polypeptides, designated Ya1 and Ya2, by reverse-phase h.p.l.c. In rat livers that possess aflatoxin B1-induced pre-neoplastic nodules, a marked increase is observed in the expression of Ya1, Ya2, Yc and Yk; of these subunits, Ya2 exhibited the greatest increase in concentration. The Ya1 and Ya2 subunits isolated from nodule-bearing livers were cleaved with CNBr, and the purified peptides were subjected to automated amino-acid-sequence analysis. Differences in the primary structures of the two Ya GST subunits were found at positions 31, 34, 107 and 117. These data demonstrate that Ya1 and Ya2 are distinct polypeptides and are the products of separate genes. The amino acid sequences obtained from Ya1 and Ya2 were compared with the cloned cDNAs pGTB 38 [Pickett, Telakowski-Hopkins, Ding, Argenbright & Lu (1984) J. Biol. Chem. 259, 4112-4115] and pGTR 261 [Lai, Li, Weiss, Reddy & Tu (1984) J. Biol. Chem. 259, 5182-5188], which encode rat Ya-type subunits. From these comparisons it appears probable that Ya1 represents the GST subunit encoded by pGTR 261, whereas Ya2 represents the subunit encoded by pGTB 38. It is likely that the over-expression of Ya1 and Ya2 in nodule-bearing livers is of major significance in the acquired resistance of nodules to aflatoxin B1, since previous work [Coles, Meyer, Ketterer, Stanton & Garner (1985) Carcinogenesis 6, 693-697] has shown that the Ya-type GST subunit has high activity towards aflatoxin B1 8,9-epoxide.

(S)-Preferential detoxification of 4-hydroxy-2(E)-nonenal enantiomers by hepatic glutathione S-transferase isoforms in guinea-pigs and rats

2001 ◽  
Vol 355 (1) ◽  
pp. 237-244 ◽  
Author(s):  
Akira HIRATSUKA ◽  
Kouichi TOBITA ◽  
Hiroshi SAITO ◽  
Yasuhiro SAKAMOTO ◽  
Hiroaki NAKANO ◽  
...  
Keyword(s):  
Guinea Pig ◽  
Guinea Pigs ◽  
High Catalytic Activity ◽  
Glutathione S Transferase ◽  
Pig Liver ◽  
Liver Cytosol ◽  
Glutathione S Transferases ◽  
Human Livers ◽  
A Minor ◽  
Guinea Pig Liver

In guinea-pig liver cytosol, racemic 4-hydroxy-2(E)-nonenal (HNE), a reactive and highly toxic product released from biomembranes by lipid peroxidation, was detoxified (S)-preferentially by GSH conjugation mediated by glutathione S-transferases (GSTs) and (R)-preferentially by NAD+-dependent oxidation mediated by aldehyde dehydrogenase (ALDH). The GST-mediated detoxification of the HNE enantiomers proceeded at much higher rates than that mediated by ALDH in guinea-pig liver cytosol. All the major guinea-pig GSTs, A1-1, M1-1, M1-2 and M1-3*, isolated from guinea-pig liver cytosol also catalysed the (S)-preferential conjugation of the HNE enantiomers. The liver and other major tissues of guinea-pigs had no immunologically detectable level of a putative GSTA4-4 orthologue, which exists as a minor GST protein in rat, mouse and human livers and exhibits extremely high catalytic activity towards HNE. All the hepatic rat GSTs, A1-1(2), A1-3, A4-4, M1-1, M1-2 and M2-2, also catalysed the (S)-preferential conjugation of HNE enantiomers.

scholarly journals Cholic acid binding by glutathione S-transferases from rat liver cytosol

1980 ◽  
Vol 185 (1) ◽  
pp. 83-87 ◽  
Author(s):  
J D Hayes ◽  
R C Strange ◽  
I W Percy-Robb
Keyword(s):  
Bile Acid ◽  
Cholic Acid ◽  
Reduced Glutathione ◽  
Binding Activity ◽  
Transferase Activity ◽  
Glutathione S Transferase ◽  
Liver Cytosol ◽  
Glutathione S Transferases ◽  
Rat Livers ◽  
Rat Liver Cytosol

Cholic acid-binding activity in cytosol from rat livers appears to be mainly associated with enzymes having glutathione S-transferase activity; at least four of the enzymes in this group can bind the bile acid. Examination of the subunit compositions of different glutathione S-transferases indicated that cholic acid binding and the ability to conjugate reduced glutathione with 1,2-dichloro-4-nitrobenzene may be ascribed to different subunits.

scholarly journals Polymorphic glutathione S-transferase subunit 3 of rat liver exhibits different susceptibilities to carbon tetrachloride: differences in their interactions with heat-shock protein 90

2003 ◽  
Vol 372 (2) ◽  
pp. 611-616 ◽  
Author(s):  
Jun MAYAMA ◽  
Takayuki KUMANO ◽  
Makoto HAYAKARI ◽  
Takehiko YAMAZAKI ◽  
Shu AIZAWA ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Heat Shock ◽  
Heat Shock Protein ◽  
Heat Shock Protein 90 ◽  
Hsp90 Inhibitor ◽  
Glutathione S Transferase ◽  
Ccl4 Administration ◽  
A Subunit ◽  
Rat Livers

Rat glutathione S-transferase (GST) subunit 3 gene has polymorphism, one type encoding Asn198-Cys199 (NC type) and another encoding Lys198-Ser199 (KS type). To examine whether the two types of GST 3-3 exhibit different susceptibilities to oxidative stress in vivo, rats were administered with CCl4, a hepatotoxin causing severe oxidative stress, and its effect on liver GST 3-3 was compared. Decrease in GST activities in liver due to CCl4 administration was more evident in NC type rats than in KS type rats, and most GST activities of KS type rats were confined to S-hexylglutathione–Sepharose, whereas those of NC type rats were not. Decreases in GST subunits 1 and 3 were more marked in NC type rats and glutathiolated NC type GST 3-3 was also detected. These results indicated that KS and NC type GST 3-3 of rat livers exhibited different susceptibilities to CCl4in vivo. A protein consisting of a subunit with molecular mass of 90 kDa was shown to bind to KS type GST 3-3 but not to NC type. This protein was identified as heat-shock protein (HSP) 90β by N-terminal amino acid sequencing and immunoblotting. A specific HSP90 inhibitor geldanamycin released their binding. There was no difference in the binding of apoptosis signal-regulating kinase 1 to GST 3-3 between NC and KS type rats. These findings suggest that HSP90 interacts with KS type GST 3-3 and thereby protects it from inactivation due to CCl4.

scholarly journals Determinants of specificity for aflatoxin B1-8,9-epoxide in Alpha-class glutathione S-transferases

1999 ◽  
Vol 339 (1) ◽  
pp. 95-101 ◽  
Author(s):  
Paul D. McDONAGH ◽  
David J. JUDAH ◽  
John D. HAYES ◽  
Lu-Yun LIAN ◽  
Gordon E. NEAL ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Substrate Specificity ◽  
High Activity ◽  
Aflatoxin B1 ◽  
Active Site ◽  
Homology Modelling ◽  
Three Dimensional ◽  
Glutathione S Transferase ◽  
Glutathione S Transferases ◽  
Aspartate Residue

We have used homology modelling, based on the crystal structure of the human glutathione S-transferase (GST) A1-1, to obtain the three-dimensional structures of rat GSTA3 and rat GSTA5 subunits bound to S-aflatoxinyl–glutathione. The resulting models highlight two residues, at positions 208 and 108, that could be important for determining, either directly or indirectly, substrate specificity for aflatoxin-exo-8,9-epoxide among the Alpha-class GSTs. Residues at these positions were mutated in human GSTA1-1 (Met-208, Leu-108), rat GSTA3-3 (Glu-208, His-108) and rat GSTA5-5 (Asp-208, Tyr-108): in the active rat GSTA5-5 to those in the inactive GSTA1-1; and in the inactive human GSTA1-1 and rat GSTA3-3 to those in the active rat GSTA5-5. These studies show clearly that, in all three GSTs, an aspartate residue at position 208 is a prerequisite for high activity in aflatoxin-exo-8,9-epoxide conjugation, although this alone is not sufficient; other residues in the vicinity, particularly residues 103–112, are important, perhaps for the optimal orientation of the aflatoxin-exo-8,9-epoxide in the active site for catalysis to occur.

scholarly journals l-alanine uptake by rat liver parenchymal and haematopoietic cells during the perinatal period

1993 ◽  
Vol 293 (3) ◽  
pp. 819-824 ◽  
Author(s):  
J V Martinez-Mas ◽  
J Casado ◽  
A Felipe ◽  
J J G Marin ◽  
M Pastor-Anglada
Keyword(s):  
Perinatal Period ◽  
Neonatal Rat ◽  
Transport Systems ◽  
Fetal Life ◽  
Adult Rats ◽  
Liver Parenchymal ◽  
Adult Rat ◽  
Haematopoietic Cells ◽  
Parenchymal Cells ◽  
Rat Livers

Alanine disposal by liver parenchymal and haematopoietic cells from 21-day fetuses, newborns and adult rats was studied. Preparations selectively enriched in either haematopoietic cells or hepatocytes were obtained by direct perfusion of fetal- and neonatal-rat livers. L-Alanine transport into liver parenchymal cells was best fitted to two Na(+)-dependent saturable systems. The high-affinity system showed a much higher activity (Vmax.) in hepatocytes from fetuses and newborns than in those from adult rats (2.4, 4.3 and 0.3 nmol/8 min per 10(6) cells for fetuses, newborns and adults respectively). Vmax. for the low-affinity component was slightly lower during the perinatal period than in the adult (about 30 nmol/8 min per 10(6) cells for hepatocytes from fetuses and newborns, versus 48 nmol/8 min per 10(6) cells for adult rat parenchymal cells). Haematopoietic cells from fetal-rat livers showed significant Na(+)-dependent L-alanine uptake which was completely abolished after birth. These results show that the transport systems involved in L-alanine uptake by liver parenchymal cells are fully developed before birth. This probably contributes to fulfilling the high requirement for neutral amino acids for protein synthesis during development. Haematopoietic cells may play an important role in liver amino acid metabolism during fetal life.

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