Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Transferases”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 307 records · Page 17Linked to original sources
PubMed2003

Glutathione and glutathione S-transferases A1-1 and P1-1 in seminal plasma may play a role in protecting against oxidative damage to spermatozoa.

OBJECTIVE: To study the levels of glutathione, glutathione S-transferase A1-1, and glutathione S-transferase P1-1 in seminal fluid of fertile and subfertile men. DESIGN: Retrospective case-control study. SETTING: Departments of gastroenterology, obstetrics and gynecology, and epidemiology and biostatistics in a university medical center. PATIENT(S): Twenty-five subfertile men visiting the fertility clinic and 25 fertile men from midwife practices were recruited. INTERVENTION(S): Collection of semen of subfertile and fertile men. MAIN OUTCOME MEASURE(S): Plasma levels of glutathione and glutathione S-transferases A1-1 and P1-1 in relation to seminal characteristics. RESULT(S): Glutathione, glutathione S-transferase A1-1, as well as glutathione S-transferase P1-1 were found in considerable amounts in seminal fluid of subfertile and fertile men. No differences between groups were found for glutathione S-transferases A1-1 and P1-1. Also, no associations with sperm count, motility, or morphology could be detected. Fertile men had significantly higher glutathione levels as compared with the case of subfertile men. Associations of glutathione with sperm motility quality (r(s) = 0.321) and abnormal sperm morphology (r(s) = -0.496) were found. CONCLUSION(S): The presence of glutathione S-transferases A1-1 and P1-1 in seminal fluid suggests a role in the protection against (oxidative) damage of spermatozoa, whereas glutathione may play a role in male fertility.

Glutathione↗
PubMed1998

Umbilical cord plasma glutathione S-transferase alpha 1-1 levels as a marker of neonatal hepatocellular integrity.

OBJECTIVE: To investigate possible delivery-related impaired neonatal hepatocellular integrity by assessment of arterial and venous umbilical cord plasma levels of glutathione S-transferase Alpha 1-1. METHODS: Glutathione S-transferase Alpha 1-1 levels were assessed in arterial and venous umbilical cord, and maternal venous plasma samples. The influence of maternal, delivery, and neonatal characteristics on arterial umbilical cord glutathione S-transferase Alpha 1-1 levels was studied, using linear regression analysis after log-transformation. RESULTS: Median (range) arterial umbilical cord glutathione S-transferase Alpha 1-1 plasma levels were higher than venous umbilical cord levels (9.68 [0.64-1125] microg/L and 7.66 [0.78-987.5] microg/L, respectively, P < .005). Median (range) arterial and venous umbilical cord glutathione S-transferase Alpha 1-1 levels were higher than, and did not correlate with, maternal venous plasma levels (8.79 [1.79-183] microg/L and 6.47 [1.58-164.5] microg/L versus 1.47 [0.46-10.4] microg/L, P < .001). Neonates born vaginally demonstrated higher median (range) levels than those delivered by cesarean (13.41 [1.02-1125] microg/L and 5.73 [0.64-172.90] microg/L, respectively, P < .001). Neonates with unfavorable pH (arterial pH under 7.20) demonstrated higher median (range) levels than those with normal pH (arterial pH at least 7.20) (15.15 [0.77-1125] microg/L and 8.82 [0.64-120.90] microg/L, respectively, P < .001). Stepwise multiple linear regression analysis showed that birth weight had the largest influence on arterial umbilical cord glutathione S-transferase Alpha 1-1 levels, followed by arterial base deficit, and route of delivery. CONCLUSION: Arterial umbilical cord glutathione S-transferase Alpha 1-1 plasma levels, being unrelated to maternal venous levels, might give a reliable impression of early neonatal hepatocellular integrity and may become an additional indicator of neonatal condition immediately after birth.

Adolescent↗
PubMed1990

Glutathione transferase in helminths.

The helminth glutathione (GSH) transferases are present as isoenzymes but fail to show a clear biochemical homology to any of the three mammalian GSH transferase families. GSH transferase is one of the major detoxification systems found in helminths, particularly high levels being found in cestodes and digeneans. Helminth GSH transferases bind a range of anthelmintics but there is limited evidence that the enzymes can conjugate anthelmintics with glutathione. Other natural substrates of helminth GSH transferase may be secondary products of lipid peroxidation including lipid hydroperoxides and reactive carbonyls. Lipid peroxidation can arise via free radicals produced by host immuno-effector cells and helminth GSH transferase may help form a defence system against immune-mediated damage. GSH transferase has also been identified as a protective antigen in schistosomiasis.

Animals↗
PubMed1982

Studies of endogenous inhibitors of microsomal glutathione S-transferase.

Glutathione S-transferase is present in rat liver microsomal fraction, but its activity is low relative to the transferase activity present in the soluble fraction of the hepatocyte. We have found, however, that the activity of microsomal glutathione S-transferase is increased 5-fold after treatment with small unilamellar vesicles made from phosphatidylcholine. The increase in activity is due to the removal of an inhibitor of the enzyme from the microsomal membrane. The inhibitor is present in the organic layer of a washed Folch extract of the microsomal fraction. When this fraction of the microsomal extract is reconstituted in the form of small unilamellar vesicles, it inhibits microsomal glutathione S-transferase that had been activated by prior treatment with small unilamellar vesicles of pure phosphatidylcholine, but does not affect the activity of unactivated microsomal glutathione S-transferase. The inhibitor did not seem to be formed during the isolation of the microsomal fraction, and hence may be a physiological regulator of microsomal glutathione S-transferase. In this regard, both free fatty acid (palmitate) and lysophosphatidylcholine were shown to inhibit the enzyme reversibly. The results indicate that the activity of microsomal glutathione S-transferase is far greater than appreciated until now, and that this form of the enzyme may be an important factor in the hepatic metabolism of toxic electrophiles.

Animals↗
PubMed1984

Inhibition of microsomal lipid peroxidation by glutathione and glutathione transferases B and AA. Role of endogenous phospholipase A2.

Lipid peroxidation in vitro in rat liver microsomes (microsomal fractions) initiated by ADP-Fe3+ and NADPH was inhibited by the rat liver soluble supernatant fraction. When this fraction was subjected to frontal-elution chromatography, most, if not all, of its inhibitory activity could be accounted for by the combined effects of two fractions, one containing Se-dependent glutathione (GSH) peroxidase activity and the other the GSH transferases. In the latter fraction, GSH transferases B and AA, but not GSH transferases A and C, possessed inhibitory activity. GSH transferase B replaced the soluble supernatant fraction as an effective inhibitor of lipid peroxidation in vitro. If the microsomes were pretreated with the phospholipase A2 inhibitor p-bromophenacyl bromide, neither the soluble supernatant fraction nor GSH transferase B inhibited lipid peroxidation in vitro. Similarly, if all microsomal enzymes were heat-inactivated and lipid peroxidation was initiated with FeCl3/sodium ascorbate neither the soluble supernatant fraction nor GSH transferase B caused inhibition, but in both cases inhibition could be restored by the addition of porcine pancreatic phospholipase A2 to the incubation. It is concluded that the inhibition of microsomal lipid peroxidation in vitro requires the consecutive action of phospholipase A2, which releases fatty acyl hydroperoxides from peroxidized phospholipids, and GSH peroxidases, which reduce them. The GSH peroxidases involved are the Se-dependent GSH peroxidase and the Se-independent GSH peroxidases GSH transferases B and AA.

Acetophenones↗
PubMed1986

Stimulation of mouse liver glutathione S-transferase activity in propylthiouracil-treated mice in vivo by tri-iodothyronine.

Female C57Bl/6J mice were given drinking water containing 0.05% propylthiouracil to induce a hypothyroid condition. Mitochondrial glycerol-3-phosphate dehydrogenase activity, used as an index of hypothyroidism, was 57.1 +/- 4.5 and 29.4 +/- 3.8 nmol/min per mg of protein for control and propylthiouracil-treated animals respectively. Administration of tri-iodothyronine resulted in an approx. 4.5-fold increase in dehydrogenase activity in propylthiouracil-treated animals. A dose-dependent increase in hepatic GSH S-transferase activity in propylthiouracil-treated animals was observed at tri-iodothyronine concentrations ranging from 2 to 200 micrograms/100 g body wt. This increase in transferase activity was seen only when 1,2-epoxy-3-(p-nitrophenoxy)propane was used as substrate for the transferase. Transferase activity with 1-chloro-2,4-dinitrobenzene and 1,2-dichloro-4-nitrobenzene as substrate was decreased by tri-iodothyronine. Administration of actinomycin D (75 micrograms/100 g body wt.) inhibited the tri-iodothyronine induction of transferase activity. Results of these studies strongly suggest that tri-iodothyronine administration markedly affected the activities of GSH S-transferase by inducing a specific isoenzyme of GSH S-transferase and suppressing other isoenzymic activities.

Animals↗
PubMed1987

Cloning of rat brain succinyl-CoA:3-oxoacid CoA-transferase cDNA. Regulation of the mRNA in different rat tissues and during brain development.

3-Oxoacid CoA-transferase, which catalyses the first committed step in the oxidation of ketone bodies, is uniquely regulated in developing rat brain. Changes in 3-oxoacid CoA-transferase activity in rat brain during the postnatal period are due to changes in the relative rate of synthesis of the enzyme. To study the regulation of this enzyme, we identified, with a specific polyclonal rabbit anti-(rat 3-oxoacid CoA-transferase), two positive cDNA clones (approx. 800 bp) in a lambda gtll expression library, constructed from poly(A)+ RNA from brains of 12-day-old rats. One of these clones (lambda CoA3) was subcloned into M13mp18 and subjected to further characterization. Labelled single-stranded probes prepared by primer extension of the M13mp18 recombinant hybridized to a 3.6 kb mRNA. Rat brain mRNA enriched by polysome immunoadsorption for a single protein of size 60 kDa which corresponds to the precursor form of 3-oxoacid CoA-transferase was also found to be similarly enriched for the hybridizable 3.6 kb mRNA complementary to lambda CoA3. Affinity-selected antibody to the lambda CoA3 fusion protein inhibited 3-oxoacid CoA-transferase activity present in rat brain mitochondrial extracts. The 3.6 kb mRNA for 3-oxoacid CoA-transferase was present in relative abundance in rat kidney and heart, to a lesser extent in suckling brain and mammary gland and negligible in the liver. The specific mRNA was also found to be 3-fold more abundant in the brain from 12-day-old rats as compared with 18-day-old foetuses and adult rats, corresponding to the enzyme activity and relative rate of synthesis profile during development. These data suggest that 3-oxoacid CoA-transferase enzyme activity is regulated at a pretranslational level.

Animals↗
PubMed1989

Human intestinal glutathione S-transferases.

Cytosolic glutathione S-transferases were purified from the epithelial cells of human small and large intestine. These preparations were characterized with regard to specific activities, subunit and isoenzyme composition. Isoenzyme composition and specific activity showed little variation from proximal to distal small intestine. Specific activities of hepatic and intestinal enzymes from the same patient were comparable. Hepatic enzymes were mainly composed of 25 kDa subunits. Transferases from small intestine contained 24 and 25 kDa subunits, in variable amounts. Colon enzymes were composed of 24 kDa subunits. In most preparations, however, minor amounts of 27 and 27.5 kDa subunits were detectable. Separation into isoforms by isoelectric focusing revealed striking differences: glutathione S-transferases from liver were mainly basic or neutral, enzymes from small intestine were basic, neutral and acidic, whereas large intestine contained acidic isoforms only. The intestinal acidic transferase most probably was identical with glutathione S-transferase Pi, isolated from human placenta. In the hepatic preparation, this isoform was hardly detectable. The specific activity of glutathione S-transferase showed a sharp fall from small to large intestine. In proximal and distal colon, activity seemed to be about equal. In the ascending colon there might be a relationship between specific activity of glutathione S-transferases and age of the patient, activity decreasing with increasing age.

Adult↗
PubMed1989

Single-step purification and h.p.l.c. analysis of glutathione transferase 8-8 in rat tissues.

GSSG selectively elutes two GSH transferases from a mixture of rat GSH transferases bound to a GSH-agarose affinity matrix. One is a form of GSH transferase 1-1 and the other is shown to be GSH transferase 8-8. By using tissues that lack this form of GSH transferase 1-1 (e.g. lung), GSH transferase 8-8 may thus be purified from cytosol in a single step. Quantitative analysis of the tissue distribution of GSH transferase 8-8 was obtained by h.p.l.c.

Animals↗
PubMed1989

Glutathione transferases in the tapeworm Moniezia expansa.

Four forms of GSH transferase were resolved from Moniezia expansa cytosol by GSH-Sepharose affinity chromatography and chromatofocusing in the range pH 6-4, and the presence of isoenzymes was further suggested by analytical isoelectric focusing. The four GSH transferase forms in the cestode showed no clear biochemical relationship to any one mammalian GSH transferase family. The N-terminal of the major GSH transferase form showed sequence homology with the Mu and Alpha family GSH transferases. The major GSH transferase appeared to bind a number of commercially available anthelmintics but did not appear to conjugate the compounds with GSH. The major GSH transferase efficiently conjugated members of the trans-alk-2-enal and trans,trans-alka-2,4-dienal series, established secondary products of lipid peroxidation.

Amino Acid Sequence↗
PubMed2003

Protein farnesyltransferase inhibitors interfere with farnesyl diphosphate binding by rubber transferase.

Rubber transferase, a cis-prenyltransferase, catalyzes the addition of thousands of isopentenyl diphosphate (IPP) molecules to an allylic diphosphate initiator, such as farnesyl diphosphate (FPP, 1), in the presence of a divalent metal cofactor. In an effort to characterize the catalytic site of rubber transferase, the effects of two types of protein farnesyltransferase inhibitors, several chaetomellic acid A analogs (2, 4-7) and alpha-hydroxyfarnesylphosphonic acid (3), on the ability of rubber transferase to add IPP to the allylic diphosphate initiator were determined. Both types of compounds inhibited the activity of rubber transferases from Hevea brasiliensis and Parthenium argentatum, but there were species-specific differences in the inhibition of rubber transferases by these compounds. Several shorter analogs of chaetomellic acid A did not inhibit rubber transferase activity, even though the analogs contained chemical features that are present in an elongating rubber molecule. These results indicate that the initiator-binding site in rubber transferase shares similar features to FPP binding sites in other enzymes.

Alkyl and Aryl Transferases↗
PubMed1977

Relationship between the soluble glutathione-dependent delta 5-3-ketosteroid isomerase and the glutathione S-transferases of the liver.

Soluble, glutathione-stimulated delta 5-3-ketosteroid isomerase (EC 5.3.3.A) activity of human and rat liver resides in very basic proteins with molecular weights of about 45,000 which are present in high concentrations in these tissues. Physiochemical and immunological evidence is presented for the identity of the proteins responsible for this enzymatic activity with the glutathione S-transferases (RX:glutathione R-transferase, EC 2.5.1.18) that conjugate glutathione with a variety of electrophilic compounds. In the rat, the steroid isomerase is associated principally with the major transferase (B), which is also known as ligandin, and has the versatility to bind various hydrophobic compounds such as bilirubin, corticosteroids, and metabolites of a number of carcinogens. Other rat liver-glutathione S-transferase species are far less active in the steroid isomerization reaction. The delta 5-3-ketosteroid isomerase activity of human liver is more uniformly distributed among the five glutathione S-transferases that have been described. Steroid isomerization differs fundamentally from other reactions promoted by glutathione S-transferases in that glutathione is not consumed in the reaction. However, because the transferase enzymes promote nucleophilic attack by glutathione on a variety of largely foreign organic substrates, a similar mechanism may be involved in the isomerase reaction. Delta 5-3-ketosteroids are among the few known naturally occurring substrates for these enzymes.

Animals↗
PubMed1998

Single prenyl-binding site on protein prenyl transferases.

Three distinct protein prenyl transferases, one protein farnesyl transferase (FTase) and two protein geranylgeranyl transferases (GGTase), catalyze prenylation of many cellular proteins. One group of protein substrates contains a C-terminal CAAX motif (C is Cys, A is aliphatic, and X is a variety of amino acids) in which the single cysteine residue is modified with either farnesyl or geranylgeranyl (GG) by FTase or GGTase type-I (GGTase-I), respectively. Rab proteins constitute a second group of substrates that contain a C-terminal double-cysteine motif (such as XXCC in Rab1a) in which both cysteines are geranylgeranylated by Rab GG transferase (RabGGTase). Previous characterization of CAAX prenyl transferases showed that the enzymes form stable complexes with their prenyl pyrophosphate substrates, acting as prenyl carriers. We developed a prenyl-binding assay and show that RabGGTase has a prenyl carrier function similar to the CAAX prenyl transferases. Stable RabGGTase:GG pyrophosphate (GGPP), FTase:GGPP, and GGTase-I:GGPP complexes show 1:1 (enzyme:GGPP) stoichiometry. Chromatographic analysis of prenylated products after single turnover reactions by using isolated RabGGTase:GGPP complex revealed that Rab is mono-geranylgeranylated. This study establishes that all three protein prenyl transferases contain a single prenyl-binding site and suggests that RabGGTase transfers two GG groups to Rabs in independent and consecutive reactions.

Alkyl and Aryl Transferases↗
PubMed1999

Modification of the ADP-ribosyltransferase and NAD glycohydrolase activities of a mammalian transferase (ADP-ribosyltransferase 5) by auto-ADP-ribosylation.

Mono-ADP-ribosylation, a post-translational modification in which the ADP-ribose moiety of NAD is transferred to an acceptor protein, is catalyzed by a family of amino acid-specific ADP-ribosyltransferases. ADP-ribosyltransferase 5 (ART5), a murine transferase originally isolated from Yac-1 lymphoma cells, differed in properties from previously identified eukaryotic transferases in that it exhibited significant NAD glycohydrolase (NADase) activity. To investigate the mechanism of regulation of transferase and NADase activities, ART5 was synthesized as a FLAG fusion protein in Escherichia coli. Agmatine was used as the ADP-ribose acceptor to quantify transferase activity. ART5 was found to be primarily an NADase at 10 microM NAD, whereas at higher NAD concentrations (1 mM), after some delay, transferase activity increased, whereas NADase activity fell. This change in catalytic activity was correlated with auto-ADP-ribosylation and occurred in a time- and NAD concentration-dependent manner. Based on the change in mobility of auto-ADP-ribosylated ART5 by SDS-polyacrylamide gel electrophoresis, the modification appeared to be stoichiometric and resulted in the addition of at least two ADP-ribose moieties. Auto-ADP-ribosylated ART5 isolated after incubation with NAD was primarily a transferase. These findings suggest that auto-ADP-ribosylation of ART5 was stoichiometric, resulted in at least two modifications and converted ART5 from an NADase to a transferase, and could be one mechanism for regulating enzyme activity.

ADP Ribose Transferases↗
PubMed2002

Rat encodes the paralogous gene equivalent of the human histo-blood group ABO gene. Association with antigen expression by overexpression of human ABO transferase.

We cloned a rat ABO homologue and established human A- and B-transferase transgenic rats. A DNA fragment corresponding to exon 7 of the human ABO gene was amplified from Wistar rat genomic DNA and sequenced. Using the amplified fragments as a probe for Southern blotting, multiple hybridized bands appeared on both EcoRI- and BamHI-digested genomes of seven rat strains, which showed variations in the band numbers among the strains. Four cDNAs were cloned from a Wistar rat, three of which showed A-transferase activity and one of which showed B-transferase activity. These activities were dependent on the equivalent residues at 266 and 268 of human ABO transferase. Wild Wistar rats expressed A-antigen in salivary gland, intestine, and urinary bladder tissue, but B-antigen was not stained in any organs studied, whereas a transcript from the ABO homologue with B-transferase activity was ubiquitous. Human A-transferase and B-transferase were transferred into Wistar rats. A-transgenic rats expressed A-antigen in ectopic tissue of the brain plexus, type II lung epithelium, pancreas, and epidermis. B-antigen in the B-transgenic rat was expressed in the same organs as A-transgenic rats. These results may shed light on the function and evolution of the ABO gene in primates.

ABO Blood-Group System↗
PubMed2003

Ure2, a prion precursor with homology to glutathione S-transferase, protects Saccharomyces cerevisiae cells from heavy metal ion and oxidant toxicity.

Ure2, the protein that negatively regulates GATA factor (Gln3, Gat1)-mediated transcription in Saccharomyces cerevisiae, possesses prion-like characteristics. Identification of metabolic and environmental factors that influence prion formation as well as any activities that prions or prion precursors may possess are important to understanding them and developing treatment strategies for the diseases in which they participate. Ure2 exhibits primary sequence and three-dimensional homologies to known glutathione S-transferases. However, multiple attempts over nearly 2 decades to demonstrate Ure2-mediated S-transferase activity have been unsuccessful, leading to the possibility that Ure2 may well not participate in glutathionation reactions. Here we show that Ure2 is required for detoxification of glutathione S-transferase substrates and cellular oxidants. ure2 Delta mutants are hypersensitive to cadmium and nickel ions and hydrogen peroxide. They are only slightly hypersensitive to diamide, which is nitrogen source-dependent, and minimally if at all hypersensitive to 1-chloro-2,4-dinitrobenzene, the most commonly used substrate for glutathione S-transferase enzyme assays. Therefore, Ure2 shares not only structural homology with various glutathione S-transferases, but ure2 mutations possess the same phenotypes as mutations in known S. cerevisiae and Schizosaccharomyces pombe glutathione S-transferase genes. These findings are consistent with Ure2 serving as a glutathione S-transferase in S. cerevisiae.

Ammonia↗
PubMed1997

Effect of long time storage on cytosolic glutathione S-transferases.

Glutathione S-transferases are a family of enzymes catalyzing the conjugation of glutathione to a wide variety of compounds. Stability of human liver cytosolic glutathione S-transferase enzyme activity and levels of glutathione S-transferase class Alpha and Mu were assessed. Cytosolic fractions of sixteen different patients were stored up to two years at three different temperatures: -20 degrees, -80 degrees and -196 degrees Celsius. Samples were assayed for glutathione S-transferase enzyme activity and glutathione S-transferase class Alpha and Mu levels, after 3, 6, 12 and 24 months of storage. No significant differences in glutathione S-transferase enzyme activity as well as in isoenzyme levels were found during this 24 months of storage at the three different temperatures. It is concluded that stability of glutathione S-transferases allows long term storage even at -20 degrees C, without significant loss of enzyme activity or enzyme protein.

Cold Temperature↗
PubMed1986

Nonhistone protein BA is a glutathione S-transferase localized to interchromatinic regions of the cell nucleus.

A DNA-binding nonhistone protein, protein BA, was previously demonstrated to co-localize with U-snRNPs within discrete nuclear domains (Bennett, F. C., and L. C. Yeoman, 1985, Exp. Cell Res., 157:379-386). To further define the association of protein BA and U-snRNPs within these discrete nuclear domains, cells were fractionated in situ and the localization of the antigens determined by double-labeled immunofluorescence. Protein BA was extracted from the nucleus with the 2.0 M NaCl soluble chromatin fraction, while U-snRNPs were only partially extracted from the 2.0 M NaCl-resistant nuclear structures. U-snRNPs were extracted from the residual nuclear material by combined DNase I/RNase A digestions. Using an indirect immunoperoxidase technique and electron microscopy, protein BA was localized to interchromatinic regions of the cell nucleus. Protein BA was noted to share a number of chemical and physical properties with a family of cytoplasmic enzymes, the glutathione S-transferases. Comparison of the published amino acid composition of protein BA and glutathione S-transferases showed marked similarities. Nonhistone protein BA isolated from saline-EDTA nuclear extracts exhibited glutathione S-transferase activity with a variety of substrates. Substrate specificity and subunit analysis by SDS polyacrylamide gel electrophoresis revealed that it was a mixture of several glutathione S-transferase isoenzymes. Protein BA isolated from rat liver chromatin was shown by immunoblotting and peptide mapping techniques to be two glutathione S-transferase isoenzymes composed of the Yb and Yb' subunits. Glutathione S-transferase Yb subunits were demonstrated to be both nuclear and cytoplasmic proteins by indirect immunolocalization on rat liver cryosections. The identification of protein BA as glutathione S-transferase suggests that this family of multifunctional enzymes may play an important role in those nuclear domains containing U-snRNPs.

Amino Acids↗