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PubMed1989

Control of expression of the human glutathione S-transferase pi gene differs from its rat orthologue.

We have examined regulation of the glutathione S-transferase pi gene by transient expression assay, and find that a fragment from 8 to 99 bp upstream of the cap site promotes transcription, but there is no evidence for any enhancer activity in a further 6 kb of flanking sequence. Analysis of this sequence by reference to a primate sequence database and Southern blotting revealed that as much as 5 kb of this flanking DNA were composed of repetitive insertion elements including an Alu and a LINE 1 repeat. The promoter fragment has been sequenced (Cowell et al (1988) Biochem. J. 255, 79-83) and contains a consensus AP1 binding site; in some cases, these have been associated with transcriptional induction by phorbol esters and ras oncogenes. We measured the steady state levels of glutathione S-transferase pi mRNA in human cell lines which were known to express ras oncogenes and compared them to human cell lines which have not been identified with ras activation. There was no correlation between expression of activated ras and expression of glutathione S-transferase pi mRNA. Treatment of HeLa cells, HepG2 cells and a small cell lung carcinoma line, GLC 8, with the phorbol ester 12-O-tetradecanoylphorbol 13-acetate failed to alter the steady state levels of endogenous glutathione S-transferase pi mRNA. The differences between these results and those of similar studies on rat glutathione S-transferase subunit 7, a structural orthologue of glutathione S-transferase pi, are discussed.

Animals↗
PubMed1984

The distribution of microsomal glutathione transferase among different organelles, different organs, and different organisms.

In the present study we have used both enzyme assay with 1-chloro-2,4-dinitrobenzene as substrate and immunochemical quantitation to examine the distribution of microsomal glutathione transferase in different organelles, in different organs, and in different organisms. This enzyme was found to constitute 3% and 5%, respectively, of the total protein recovered in the microsomal and outer mitochondrial membrane fractions from rat liver. Microsomal glutathione transferase present in other subcellular fractions can be accounted for by contamination by the endoplasmic reticulum. In contrast to the situation with rat liver microsomes the glutathione transferase activities of microsomes from extrahepatic tissues of this same animal could not be activated by treatment with N-ethylmaleimide. Nonetheless, significant albeit low levels of a protein with the same molecular weight and immunochemical properties as the rat liver enzyme could be detected in microsomes from several extrahepatic tissues, notably the intestine, the adrenal, and the testis. Of those mammals for which fresh liver could be obtained, all demonstrated N-ethylmaleimide-activatable glutathione transferase activity in their liver microsomes. On the other hand, representatives for fish, birds, and amphibia did not demonstrate such activatable transferase activity in their liver microsomes. Toad was the only species that had a notable (twofold) sex difference in their level of hepatic microsomal glutathione transferase activity.

Animals↗
PubMed1988

Effects of butylated hydroxyanisole on glutathione S-transferase and catechol O-methyltransferase activities in Syrian golden hamsters.

The effects of dietary butylated hydroxyanisole (BHA) on the enzyme activities of glutathione (GSH) S-transferase and catechol O-methyltransferase (COMT) in the forestomach, small intestinal mucosa, and liver of Syrian golden hamsters and ICR/Ha mice were examined. GSH S-transferase activity in the hamster tissues was not enhanced appreciably after 1 or 4 weeks of feeding diets containing various concentrations of BHA. In general, short term (1 week) feeding of diets containing BHA did not differ from longer term (4 weeks) feeding of the same diets. In the forestomach of hamsters, a positive dose response on the activity of GSH S-transferase was obtained with increasing concentration of BHA in the diet for 1 or 4 weeks. The maximum effect of dietary BHA in hamsters was observed in the forestomach after 1 week of feeding, which induced an increase in GSH S-transferase activity to twice that of the control level. The same induction effect, however, was not apparent in the liver or in the small intestinal mucosa. Dietary BHA, at all concentrations studied, did not elicit any significant change in the activity of the GSH S-transferase enzyme in these two tissues. While the increase of enzyme activity in the forestomach of ICR/Ha mice was similar to that observed in the forestomach of hamsters, the induction of GSH S-transferase activity in the liver and in the small intestinal mucosa of the two animal species was drastically different. In contrast to the lack of response to dietary BHA in the hamster tissues, the induction of increased enzyme activity in the liver and intestinal mucosa of ICR/Ha mice, after 1 week of 2% BHA feeding, was greater than 7 and 11 times that of control respectively. The ineffectiveness of BHA as an enzyme inducer in the hamster tissues was similar for the activity of COMT. The enzyme activity in all three hamster tissues examined did not change significantly as a result of BHA incorporation into the diet for 1 week. In contrast, the COMT activity in the forestomach and small intestinal mucosa of the mouse was increased with increasing concentration of dietary BHA. At 2% BHA, the enzyme activity in the two tissues was 3 and 2 times that of the control level, respectively, whereas the enzyme activity in the liver remained at control level. These findings suggest that the overall unresponsiveness of detoxifying enzyme systems in the Syrian golden hamsters may be critical in the formation of forestomach tumors caused by BHA.

Animals↗
PubMed1988

Halothane: inhibition and activation of rat hepatic glutathione S-transferases.

Multiple halothane anesthesias (1.25 MAC for 1 hr on 3 alternate days) of male Long-Evans rats initially decreased by up to 30% and subsequently increased to up to 185% liver cytosolic glutathione S-transferase activity toward 1-chloro-2,4-dinitrobenzene, 3,4-dichloro-1-nitrobenzene and trans-4-phenyl-3-buten-2-one and glutathione peroxidase activity. Halothane rapidly and reversibly activated hepatic cytosolic glutathione S-transferases and purified isoenzyme 1-2 but not isoenzymes 1-1 and 3-3. At high concentrations of halothane (ca. 22 mM), maximal activation was ca. 25%. Halothane, enflurane, isoflurane and methoxyflurane, but not the halothane metabolite 1-chloro-2,2-difluoroethylene, inhibited a mixture of liver cytosolic glutathione S-transferases with time (ca. 30% inhibition/15 min). The inhibition exhibited pseudo-first order kinetics (kobs = 0.13 min-1) and an I50 for halothane of greater than or equal to 15 mM. Halothane inhibited glutathione S-transferases 3-3, 3-4, and 4-4 by 50-60%, but did not affect isoenzymes 1-1 and 1-2. The ability of halothane to diminish hepatic glutathione S-transferase activity in vivo may in part reflect the time-dependent inhibition of glutathione S-transferase isoenzymes containing the 3- and 4-subunits.

Anesthesia↗
PubMed1989

Electrophoretic and immunological analysis of glutathione transferase isoenzymes of human kidney carcinoma.

By sequential use of GSH-affinity chromatography and chromatofocusing, the isoenzymes of glutathione transferase from tumor and non-tumor kidney tissues have been purified and their properties compared. On the basis of electrophoretic mobilities on SDS/polyacrylamide gel, substrate specificities toward the diagnostic substrates cumene hydroperoxide and ethacrynic acid and immunoreactivity with antisera raised against alpha, mu and pi class glutathione transferases, it was found that most of the isoenzymes purified from both tumor and non-tumor kidney can be identified as members of either alpha or pi classes. All the samples investigated lacked mu class glutathione transferase. In addition, we could identify in tumor samples two transferases GST-7.6 and GST-5.8/5.9 which on the basis of immunological properties cannot be related to any of the members of the three major classes of glutathione transferases. The latter do not appear to have corresponding forms in non-tumor tissues. It was suggested that specific transferases can be selectively expressed by tumor kidney carcinoma.

Carcinoma, Renal Cell↗
PubMed1979

The interactions of triethyltin with rat glutathione-S-transferases A, B and C. Enzyme-inhibition and equilibrium-dialysis studies.

Purified glutathione(GSH)-S-transferases A, B and C from rat liver are inhibited by triethyltin (SnEt3). With 1-chloro-2,4-dinitro benzene (CDNB) as the limiting substrate the inhibition is competitive in each case. At a GSH concentration of 5 . 10(-3) M the inhibition constants for transferases A and C at 25 degrees C are similar and very low, 3.2 . 10(-8) M and 5.6 . 10(-8) M respectively, whereas for transferase B the inhibition constant is 3.5 . 10(-5) M. Equilibrium-dialysis experiments carried out at 4 degrees C in the absence of GSH give apparent dissociation constants of 7.1 . 10(-4) M and 3.4 . 10(-4) M for transferases A and B respectively, but if 5 . 10(-3) M glutathione is included in the dialysis solutions these values fall to 2.0 . 10(-7) M and 2.6 . 10(-5) M, which are within an order of magnitude of the kinetic Ki-values. Chromatographic experiments with Sephadex G-10 show that GSH and SnEt3 interact in aqueous solution under the conditions of the enzyme-kinetic and equilibrium-dialysis experiments. It is suggested that the inhibited enzymes are in the form of ternary complexes, enzyme-GSH-SnEt3, in which GSH and SnEt3 may or may not interact directly; or are possibly quaternary complexes, enzyme-(GSH)2-SnEt3. SnEt3 could be valuable as a selective inhibitor of transferases A and C in mixtures of the three transferases.

Animals↗
PubMed1983

The requirement for glutathione S-transferase in the conjugation of activated aflatoxin B1 during aflatoxin hepatocarcinogenesis in the rat.

The formation of an aflatoxin B1-reduced glutathione (AFB1-GSH) conjugate in in vitro systems has been examined. AFB1 was activated by a chicken liver microsomal system and factors affecting the subsequent conversion to the AFB1-dihydrodiol or conjugation with GSH were investigated by HPLC. A requirement for glutathione S-transferase in the formation of the AFB1-GSH conjugate was observed. Studies using CM-cellulose columns showed the fractions containing glutathione S-transferase B activity were the most effective in catalysing the formation of the AFB1-GSH conjugate. The possibility of changes in the level of AFB1-GSH conjugate production in the liver during carcinogenesis by AFB1 has been examined. It has been found, using freshly isolated rat hepatocytes, that low level feeding with AFB1 in vivo increases the production of the conjugate in vitro. Further increases in the production of the conjugate by hepatocytes in vitro, accompanying increases in the preneoplastic lesions, are achieved by partially hepatectomising the AFB1-fed animals. Partial hepatectomy of control-fed animals yielded no similar changes. The AFB1/partial hepatectomy treatment resulted in increased levels of all the glutathione S-transferase activities fractionated on CM-cellulose. Macromolecular binding of AFB1 and/or of its metabolites was detected in the fractions containing glutathione S-transferase activity, but there was no evidence for a greater binding in the glutathione S-transferase B/ligandin containing fractions. Furthermore fractionation on Sephadex G-75 indicated a predominance of binding of AFB1 to proteins of a higher molecular weight than the glutathione S-transferases, although some binding in the molecular weight range of the latter was observed.

Administration, Oral↗
PubMed1984

The hepatic glutathione transferases of the male little skate, Raja erinacea.

Five cytosolic glutathione transferases were isolated from the liver of the male little skate, Raja erinacea, a marine elasmobranch. They were designated E-1 through E-5 in order of their elution from a DEAE-cellulose column with a 0 to 100 mM KCl gradient in 0.01 M Tris (pH 8.0). Each eluted peak of glutathione transferase activity, after concentration, was applied to an affinity column prepared by reaction of epoxy-activated Sepharose 6B with glutathione (GSH). Elution of the various glutathione transferases from this column with GSH resulted in the further purification of each enzyme; the major glutathione transferase, E-4 and E-1, were purified to apparent homogeneity by this procedure. Skate glutathione transferase E-4 is dimeric and the subunits are either very similar or identical in molecular weight (about 26 000 daltons). Enzymes E-2 through E-5 were acidic proteins (pI less than 7.0) and had high specific glutathione transferase activity (0.3--12 mumol/min/mg protein) with benzo[a]pyrene 4,5-oxide (BPO) as substrate, whereas the other enzyme (E-1) had low activity (0.01 mumol/min/mg) with BPO and a basic pI (greater than 9.5). Bilirubin and hematin, non-substrate ligands, bound tightly to homogeneous E-4, with dissociation constants in the micromolar range.

Animals↗
PubMed1980

Serum glutathione S-transferase activity in liver diseases.

Assay conditions of human liver glutathione S-transferase and its activity in human serum from liver disease patients were investigated. One mmol/l reduced glutathione, and 1 mmol/l-1-chloro-2,4-dinitrobenzene, pH 6.5, were used for the measurement, because of the very low non-enzymatic conjugation. Glutathione S-transferase activity was inhibited by bilirubin, but this inhibition was counteracted by the presence of a low concentration of albumin. The normal human serum glutathione S-transferase activity was 5.2 +/- 2.4 I.U./l (mean +/- S.D.), and was not influenced by any differences of age, sex or leukocyte count. A significant increase in serum enzyme activity was noted in cases of acute hepatitis with GPT exceeding 200 I.U./l, primary hepatoma and metastatic liver cancer. Some of the cases with fulminant hepatitis showed extremely high values. The degree of correlation between serum glutathione S-transferase and GOT or GPT was high in acute hepatitis, with GOT or GPT exceeding 200 I.U./l, in fulminant hepatitis, primary hepatoma and gall stones, while in chronic hepatitis and liver cirrhosis it was low. In cases of acute hepatitis and fulminant hepatitis, the disappearance of serum glutathione S-transferase from the blood was much faster than that of GOT and GPT. Serum glutathione S-transferase measurements will provide new and unique information for the diagnosis of acute liver diseases.

Adult↗
PubMed1983

Non-selenium-dependent glutathione peroxidase activity in rat lung: association with lung glutathione S-transferase activity and the effects of hyperoxia.

To determine if non-selenium-dependent glutathione peroxidase (Non-Se GSH-Px) activity is present in rat lung, we fractionated rat lung soluble fractions from rats fed a selenium-deficient or control diet and measured glutathione peroxidase activity with both cumene hydroperoxide and hydrogen peroxide as substrates. We also measured glutathione S-transferase (GSH S-transferase) activity in the fractions with 1-chloro-2,4-dinitrobenzene as substrate. Non-Se GSH-Px activity was present (about 34% of total GSH-Px activity), and the peak present in the gel filtration chromatogram coeluted with the GSH S-transferase peak. We then measured GSH S-transferase activity in lung-soluble fractions from rats exposed to room air or 85% O2 for 5 days. Lung GSH S-transferase activity was increased in the oxygen-exposed animals when compared to the air-exposed controls. The increase in GSH S-transferase activity could represent the induction of lung non-Se GSH-Px activity.

Animals↗
PubMed1981

Activities of 3-oxo acid-CoA transferase and acetoacetyl-CoA synthetase in brain and liver of the developing chick.

The 3-oxo acid-CoA transferase and acetoacetyl-CoA synthetase activities were estimated in subcellular fractions isolated from the cerebral hemispheres, the optic lobes, the cerebellum and the liver of the chick between the twentieth day of embryonic life and the thirtieth day of postnatal development. In the 3 areas of chick brain, the transferase activity increases during the whole postnatal development. Transferase is located both in mitochondria and microsomes unlike in the rat brain where this enzyme is specifically mitochondrial. There is no detectable activity of synthetase in the chick brain. These differences in enzyme localization imply that acetoacetate is converted into acetoacetyl-CoA only by 3-oxo acid-CoA transferase in the mitochondria and cytoplasm of the chick brain, whereas, in the rat brain, this reaction is performed by 3-oxo acid-CoA transferase in mitochondria and by acetoacetyl-CoA synthetase in the cytosol. There is no detectable activity either for transferase or for synthetase in the chick liver.

Aging↗
PubMed1988

Comparison of the effects of bile acids and GSH on the fluorescence of bound 1-anilino-8-naphthalene sulfonate and the enzymatic activity of cationic and neutral human hepatic GSH S-transferases.

Three cationic (C1, C2, A1) and a neutral (N1) glutathione (GSH) S-transferase were purified to homogeneity from human liver, as we have previously reported. GSH had no effect on the fluorescence of 1-anilino-8-naphthalene sulfonate (ANS) bound by transferase C1 and N1, but markedly enhanced the fluorescence with C2 and A1 without changing the affinity for ANS. This effect of GSH was saturable and with C2 was intermediate between A1 and C1. Bile acids inhibited the fluorescence of ANS bound to C1 and C2. GSH in the presence of bile acids further decreased the fluorescence of ANS bound to C1 and increased the fluorescence with C2. Transferase A1 showed decreased fluorescence in the presence of lithocholic acid and increased fluorescence in the presence of cholic acid; both changes were reversed by GSH. Transferase N1 showed increased fluorescence of bound ANS in the presence of various bile acids and this effect was diminished in the presence of GSH. Enzyme activity of the transferase was inhibited by bile acids with the exception of transferase A1. All the proteins bound lithocholic acid. The inhibition of C1 and N1 was greater at pH 6.5 than 7.4 and the order of addition of substrates and inhibitor made no difference.

Anilino Naphthalenesulfonates↗
PubMed1990

Glutathione S-transferase subunit induction patterns of Brussels sprouts, allyl isothiocyanate and goitrin in rat liver and small intestinal mucosa: a new approach for the identification of inducing xenobiotics.

Effects of Brussels sprouts (2.5-30%), allyl isothiocyanate (0.03 and 0.1%) and goitrin (0.02%), in the diet, on the glutathione S-transferase subunit pattern in the liver and small intestinal mucosa of male Fisher rats were investigated. A statistically significant linear relationship was found between the amount of Brussels sprouts in the diet and the induction of glutathione S-transferase subunits in two experiments. Increases in total activity of glutathione S-transferases towards 1-chloro-2,4-dinitrobenzene ranged from about 15% (2.5% Brussels sprouts in the diet) to 180% (30% Brussels sprouts in the diet) in the liver, and from 3% (2.5% Brussels sprouts) to 150% (30% Brussels sprouts) in the small intestinal mucosa. There were similar increases in the total amounts of glutathione S-transferase subunits. In the first experiment, when the average sinigrin and progoitrin levels found in the sprouts were 1835 and 415 mumol/kg, respectively, subunit induction patterns in both the liver and the small intestinal mucosa were very similar to the pattern observed after feeding allyl isothiocyanate. In the second experiment, when the average sinigrin level found in the sprouts was as low as the progoitrin level (both about 540 mumol/kg), a goitrin-like induction pattern was observed. The most pronounced difference between the glutathione S-transferase subunit induction patterns due to administration of allyl isothiocyanate and goitrin is the much stronger enhancement of subunit 2 by allyl isothiocyanate. The induction patterns of both experiments indicate that in Brussels sprouts at least two compounds, probably allyl isothiocyanate and goitrin, are responsible for the induction of glutathione S-transferases.

Animals↗
PubMed1985

Hepatic glutathione S-transferases in rainbow trout and their interaction with 2,4-dichlorophenoxyacetic acid and 1,4-benzoquinone.

Glutathione S-transferase in the cytosol of rainbow trout liver was partially purified by affinity chromatography on a column with glutathione coupled to epoxy-activated Sepharose 6B, which retained 94% of the total activity. Chromatofocussing on a Polybuffer exchanger 118 column separated the glutathione S-transferase into six major cationic isoenzymes (K1-K6), and some minor fractions. SDS-polyacrylamide slab gel electrophoresis showed K1-K3 to be heterodimers with subunits of Mr 25,000 and 26,500, and K4-K6 to be homodimers with subunits of Mr 25,000. The glutathione S-transferase isoenzymes were partially characterized by different biochemical parameters. The hepatic rainbow trout glutathione S-transferases were inhibited by the organic water pollutants, 1,4-benzoquinone and 2,4-dichlorophenoxyacetic acid. The same kinetic inhibition patterns were observed with these inhibitors as for rat liver glutathione S-transferases. It is concluded that rainbow trout glutathione S-transferases can play a key role in the detoxication of organic micropollutants in the aquatic environment.

2,4-Dichlorophenoxyacetic Acid↗
PubMed2000

Polymorphism in the glutathione S-transferase P1 gene and risk for preeclampsia.

OBJECTIVE: To determine whether genetic variability in biotransformation enzymes contributes to individual differences in susceptibility to preeclampsia or the syndrome of hemolysis, elevated liver enzymes, and low platelets (HELLP). METHODS: Polymorphisms in the genes of glutathione S-transferases and cytochrome P-450 1A1 were assessed by polymerase chain reaction in 170 nonpregnant women with a history of preeclampsia, 90 of whom had HELLP syndrome, and 109 healthy control women with an uncomplicated obstetric history. chi(2) analysis was used for statistical evaluation of differences in polymorphism rates. RESULTS: A higher frequency of the glutathione S-transferase P1b-1b genotype was observed in preeclamptic women than in controls (14% in preeclampsia and 5% in controls; odds ratio 3.4, 95% confidence interval 1.2, 10. 6, P =.02). Genetic polymorphisms in other glutathione S-transferases and cytochrome P-450 1A1 genes occurred equally frequently in cases and controls. In women with a history of preeclampsia, there were no differences in the occurrence of the genetic polymorphisms investigated in women who either did or did not develop the HELLP syndrome. CONCLUSION: Women with the glutathione S-transferase P1b-1b genotype, which could result in lower glutathione S-transferase detoxification capacity, might have higher susceptibility to preeclampsia. However, polymorphisms in glutathione S-transferase genes do not seem to be a risk factor for development of the HELLP syndrome.

Adult↗
PubMed1988

Glutathione transferase in the urine: a marker for post-transplant tubular lesions.

Basic glutathione transferase released from the proximal tubular epithelium in the kidney was monitored in the urine of 69 recipients of renal allografts. The enzyme was isolated from human liver and the urinary analysis performed with radioimmunoassay. Patients receiving cyclosporine A without toxicity or rejection did not excrete this enzyme in their urine; whereas the urine of patients with cyclosporine A-induced nephrotoxicity contained significant amounts of the transferase (P less than 0.001). Patients with allograft rejection also showed increased urinary concentrations of the basic glutathione transferase, but had significantly lower values than patients with cyclosporine induced nephrotoxicity (P less than 0.001). During aminoglycoside and co-trimoxazole treatment, the urinary concentration of this transferase also increased. Patients with renal infarction showed a sudden increase in urinary transferase to very high levels. The results indicate that quantitative analysis of the basic glutathione transferase in urine is useful for monitoring renal tubular lesions present in various complications following transplantation, such as cyclosporine and antibiotic induced nephrotoxicity and renal infarction.

Adolescent↗
PubMed1981

Glutathione S-transferases in elasmobranch liver. Molecular heterogeneity, catalytic and binding properties, and purification.

In order to gain insight into the phylogeny and physiological significance of organic-anion-binding proteins in the liver, the hepatic glutathione S-transferases of rat and a typical elasmobranch, the thorny-back shark (Platyrhinoides triseriata), were compared with respect to both glutathione S-transferase activites and organic-anion-binding properties. On gel filtration (Sephadex G-75, Superfine grade) of rat cytosol, the elution volumes of enzyme activities with 1-chloro-2,4-dinitrobenzene and p-nitrobenzyl chloride as substrates were identical (rat Y-fractions; M(r) 45000). In contrast, two peaks of enzyme activity for 1-chloro-2,4-dinitrobenzene with elution volumes corresponding to M(r) 52000 (PLAT Y(1)) and M(r) 45000 (PLAT Y(2)) were detected on gel filtration of P. triseriata cytosol. Only fraction PLAT Y(2) had enzyme activity with p-nitrobenzyl chloride. Enzyme kinetic studies showed that rat Y-fraction had higher affinities for both 1-chloro-2,4-dinitrobenzene and glutathione than PLAT Y(1)- and PLAT Y(2)-fractions. The two forms of P. triseriata glutathione S-transferases differed greatly in affinity for glutathione. At a glutathione concentration that we found to be physiological in P. triseriata, PLAT Y(2) accounted for approx. 70% of the total glutathione S-transferase activity with 1-chloro-2,4-dinitrobenzene. Binding studies revealed that PLAT Y(1) and PLAT Y(2) fractions had much lower affinities for sulphobromophthalein and bilirubin than rat Y-fraction. In contrast, binding affinities of PLAT Y(1) and PLAT Y(2) for Rose Bengal and 1-anilino-8-naphthalenesulphonate were comparable with that of rat Y-fraction. Inhibitory kinetics suggested that sulphobromophthalein and Rose Bengal were non-competitive inhibitors of glutathione S-transferase activities when 1-chloro-2,4-dinitrobenzene was used as substrate for both PLAT Y(1) and PLAT Y(2). The major glutathione S-transferase from the PLAT Y(2) fraction was purified 81-fold by sequential chromatography on Sephadex G-75, DEAE-Sephadex and hydroxyapatite, and consisted of two identical subunits with pI7.7. The highly enriched Y(2)-fraction retained high affinity binding of Rose Bengal and 1-anilino-8-naphthalenesulphonate.

Amino Acids↗
PubMed1984

Rat lung glutathione S-transferases. Evidence for two distinct types of 22000-Mr subunits.

Two immunologically distinct types of 22000-Mr subunits are present in rat lung glutathione S-transferases. One of these subunits is probably similar to Ya subunits of rat liver glutathione S-transferases, whereas the other subunit Ya' is immunologically distinct. Glutathione S-transferase II (pI7.2) of rat lung is a heterodimer (YaYa') of these subunits, and glutathione S-transferase VI (pI4.8) of rat lung is a homodimer of Ya' subunits. On hybridization in vitro of the subunits of glutathione S-transferase II of rat lung three active dimers having pI values 9.4, 7.2 and 4.8 are obtained. Immunological properties and substrate specificities indicate that the hybridized enzymes having pI7.2 and 4.8 correspond to glutathione S-transferases II and VI of rat lung respectively.

Animals↗