Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

---

Query: EC:2.5.1.18 (glutathione S-transferase)
22,582 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Periportal and perivenous rat liver parenchymal cells were isolated according to the digitonin-collagenase perfusion method. Affinities and maximal specific binding of a conjugate of glutathione S-transferase and the alpha 2-macroglobulin receptor-associated protein (GST-39kDaP), of lactoferrin and of transferrin to freshly isolated periportal parenchymal cells in vitro were not significantly different from values obtained with perivenous cells. It is concluded that the receptors for these three ligands show a zonally homogeneous expression in rat liver. The zonal homogeneity in binding observed for GST-39kDaP is at variance with the 1.5-fold higher periportal over perivenous binding of trypsin-activated alpha 2-macroglobulin. Since GST-39kDaP as well as trypsin-activated alpha 2-macroglobulin are ligands for the alpha 2-macroglobulin receptor/low-density lipoprotein receptor-related protein, it is suggested that GST-39kDaP can bind to (an) additional receptor(s) with a higher perivenous expression. The zonal homogeneity observed with lactoferrin, an inhibitor of ligand binding to the lipoprotein remnant receptor, may indicate zonal homogeneity of the lipoprotein remnant receptor. The observed zonal homogeneity of the transferrin receptor suggests an equal and essential need for iron by parenchymal cells across the rat liver acinus in vivo.
...
PMID:Zonal distribution of receptor binding of trypsin-activated alpha 2-macroglobulin, alpha 2-macroglobulin receptor-associated protein, lactoferrin and transferrin on rat liver parenchymal cells. 754 60

Maspin, a novel mammary serine protease inhibitor, was shown to have tumor suppressing activity (Zou, Z., Anisowicz, A., Hendrix, M. J. C., Thor, A., Neveu, M., Sheng, S., Rafidi, K., Seftor, E., and Sager, R. (1994) Science 263, 526-529). In this paper, we report the production of recombinant glutathione S-transferase-maspin fusion protein, expressed in the bacterium Escherichia coli, and recombinant maspin, expressed in the insect Spodoptera frugiperda cells. The fusion protein was purified by glutathione affinity chromatography. Maspin expressed in insect cells was purified by a combination of Bio-Rad AG1-2X anion exchange chromatography and heparin affinity chromatography. The recombinant maspin from insect cells was cleaved at the putative reactive center, as confirmed by protein sequencing. Both recombinant proteins demonstrated strong inhibitory effects on the invasion by two breast tumor cell lines across reconstituted basement membranes and such inhibitory effect was abolished in the presence of the polyclonal antibody made against the reactive center region of maspin. The trypsin-cleaved recombinant maspin did not inhibit invasion, indicating that the inhibitory activity requires the intact putative reactive center. This paper provides evidence that recombinant maspin protein itself inhibits invasion, and supports the role of maspin as a tumor suppressor.
...
PMID:Production, purification, and characterization of recombinant maspin proteins. 798 35

Hepatic mitochondria from different mammalian species contain varying levels of glutathione S-transferase (GST) activities. More than 70% of the activity detectable in the mouse liver mitochondria is associated with the soluble matrix. The mouse mitochondrial matrix GST was purified using a combination of (NH4)2SO4 fractionation, Sephadex gel filtration and affinity chromatography on glutathione (GSH) conjugated Sepharose. The purified GST comigrates with the mouse cytosolic MI (or alpha form), and exhibits an apparent molecular mass of 25 kD on sodium dodecyl sulfate-polyacrylamide gels. Polyclonal antibody to the purified mitochondrial GST cross-reacted with the similarly migrating cytosolic MI GST, suggesting extensive immunochemical relatedness between these two forms. As previously demonstrated for the cytosolic alpha form, the mitochondrial GST catalyzes aflatoxin B1-GSH conjugation (6.3 nmol/mg protein/min) and exhibits peroxidase activity (6.7 mumol/mg protein/min). The putative mitochondrial GST only in intact mitochondria, but not in sonic disrupted mitochondria, is resistant to proteolytic digestion with trypsin, demonstrating its intramitochondrial location. Isoelectric focusing on the flat bed polyacrylamide gel system resolves the mitochondrial GST into two distinct components with apparent pI of 9.9 and 9.7, both of which cross-react with polyclonal antibody to the mitochondrial GST. Under the identical conditions, the most cationic form of cytosolic GST cross-reacting intensely with the antibody resolves as a single component with an apparent pI of 9.4. Thus the mitochondrial GST resembles the alpha family of isoenzymes, though it appears to represent independent molecular species different from the cytosolic forms.
...
PMID:Purification and characterization of a hepatic mitochondrial glutathione S-transferase exhibiting immunochemical relationship to the alpha-class of cytosolic isoenzymes. 816 Dec 25

A glutathione S-transferase (GST) isozyme from maize (Zea mays Pioneer hybrid 3906) treated with the dichloroacetamide herbicide safener benoxacor (CGA-154281) was purified to homogeneity and partially characterized. The enzyme, assayed with metolachlor as a substrate, was purified approximately 200-fold by ammonium sulfate precipitation, anion-exchange chromatography on Mono Q resins, and affinity chromatography on S-hexylglutathione agarose from total GST activity present in etiolated shoots. The purified protein migrated during sodium dodecyl sulfate-polyacrylamide gel electrophoresis (PAGE) as a single band with a molecular mass of 27 kD. Using nondenaturing PAGE, we determined that the native protein has a molecular mass of about 57 kD and that the protein exists as a dimer. Two-dimensional electrophoresis revealed only a single protein with an isoelectric point of 5.75 and molecular mass of 27 kD. These results further suggest that the protein exists as a homodimer of two identical 27-kD subunits. The enzyme was most active with substrates possessing a chloroacetamide structure. trans-Cinnamic acid and 1-chloro-2,4-dinitrobenzene were not effective substrates. Apparent Km values for the enzyme were 10.8 microM for the chloroacetamide metolachlor and 292 microM for glutathione. The enzyme was active from pH 6 to 9, with a pH optimum between 7.5 and 8. An apparently blocked amino terminus of the intact protein prevented direct amino acid sequencing. The enzyme was digested with trypsin, and the amino acid sequences of several peptide fragments were obtained. The sequence information for the isolated GST we have designated "GST IV" indicates that the enzyme is a unique maize GST but shares some homology with maize GSTs I and III.
...
PMID:Purification and characterization of a glutathione S-transferase from benoxacor-treated maize (Zea mays). 827 34

Limited proteolysis experiments have been carried out on human placental glutathione transferase in its different forms. The reduced enzyme, as well as the oxidized form and that inactivated with cystamine were all sensitive to 10% (w/w) trypsin, under nondenaturing conditions. The proteolytic cleavage was accompanied by a concomitant loss of enzymatic activity. On the contrary, the presence of glutathione or glutathione conjugates strongly protected the reduced enzyme against inactivation and from the proteolytic attack. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis and peptide sequence analysis showed that only the peptide bond between Lys 44 and Ala 45 was cleaved. Since Lys 44 has been demonstrated to be involved in the glutathione binding, it is suggested that the region surrounding this amino acid residue (alpha B helix) could be more exposed to the solvent, in the absence of glutathione. Crystallographic data also indicated that this region is flexible, supporting the idea that it may be involved in the observed conformational change upon glutathione binding.
...
PMID:Conformational states of human placental glutathione transferase as probed by limited proteolysis. 834 64

The complete amino acid sequence of glutathione transferase from Proteus mirabilis was determined. The sequence was reconstructed by analysis of peptides obtained after cleavage by trypsin, Glu-C and Asp-N endoproteinases. The enzyme subunit is composed of 203 amino acid residues corresponding to a molecular mass of 22856 Da. Comparison of this sequence with other known primary structures of the corresponding enzyme from different sources shows a low level of identity (17-26%) with only seven conserved residues in all the sequences considered. This novel glutathione transferase could represent the prototype of a new class, possibly including other bacterial enzymes.
...
PMID:The amino acid sequence of glutathione transferase from Proteus mirabilis, a prototype of a new class of enzymes. 843 5

A recombinant plasmid containing the coding regions for Acacia confusa trypsin inhibitor (ACTI) has been constructed and expressed in Escherichia coli cells, as a fusion protein between ACTI and glutathione S-transferase (GST). The GST-fusion was produced as a soluble protein which did not require denaturing agents such as urea to solubilize it. The recombinant ACTI (reACTI) was obtained by treating the GST-fusion protein with thrombin. Both the reACTI and fusion protein have a strong inhibitory effect on trypsin activity without post-translational proteolysis.
...
PMID:Cloning and expression of the gene encoding Acacia confusa trypsin inhibitor that is active without post-translational proteolysis. 850 Jul 64

Long-chain L-alpha-hydroxy acid oxidase from rat kidney is a member of the family of FMN-dependent alpha-hydroxy-acid-oxidizing enzymes. With the knowledge of the recently determined amino acid sequence, the cDNA encoding the enzyme has now been cloned using the polymerase chain reaction. The 1648-bp cDNA contains an open reading frame coding for the 352 residues of the previously determined sequence, preceded by a methionine codon. In addition, several clones were found to present a nine-base insertion, predicting the existence of an isoform with a tripeptide VRK inserted between residues 188 and 189 of the mature protein. The presence of about 10% of this isoform in the oxidase purified from rat kidney was indeed identified by amino acid sequencing. A recombinant active enzyme was obtained as a protein fused to glutathione S-transferase using the bacterial expression plasmid pGEX-3X. Physico-chemical characterization indicated, for the fused enzyme, properties similar to those of the rat kidney protein. When the chimaera was submitted to factor Xa, proteolysis at the engineered cleavage point was poor. Separation of hydroxy acid oxidase from glutathione S-transferase could not be achieved with trypsin either. With both proteases, the initial cleavage point appeared to be in a peptide loop internal to the hydroxy acid oxidase sequence, close to or in the tripeptide insertion locus and not at the engineered factor-Xa-cleavage point. Comparative tryptic proteolysis of the rat kidney enzyme yielded a form cleaved in the same loop.
...
PMID:Molecular cloning and nucleotide sequence of cDNA encoding rat kidney long-chain L-2-hydroxy acid oxidase. Expression of the catalytically active recombinant protein as a chimaera. 850 89

The function of the long propeptides of fungal proteinases is not known. Aspergillus fumigatus produces a 33-kDa serine proteinase of the subtilisin family and a 42-kDa metalloproteinase of the thermolysin family. These extracellular enzymes are synthesized as preproenzymes containing large amino-terminal propeptides. Recombinant propeptides were produced in Escherichia coli as soluble fusion proteins with glutathione S-transferase or thioredoxin and purified by affinity chromatography. A. fumigatus serine proteinase propeptide competitively inhibited serine proteinase, with a Ki of 5.3 x 10(-6) M, whereas a homologous serine proteinase from A. flavus was less strongly inhibited and subtilisin was not inhibited. Binding of metalloproteinase propeptide from A. fumigatus to the mature metalloenzyme was demonstrated. This propeptide strongly inhibited its mature enzyme, with a Ki of 3 x 10(-9) M, whereas thermolysin and a metalloproteinase from A. flavus were not inhibited by this propeptide. Enzymatically inactive metalloproteinase propeptide complex could be completely activated by trypsin treatment. These results demonstrate that the propeptides of the fungal proteinases bind specifically and inhibit the respective mature enzymes, probably reflecting a biological role of keeping these extracellular enzymes inactive until secretion.
...
PMID:Specific inhibition of mature fungal serine proteinases and metalloproteinases by their propeptides. 863 20

The proteolytic attack of bacterial glutathione S-transferase (GSTB1-1) by trypsin cleaves and inactivates the enzyme. The polypeptide portion of GSTB1-1 encompassing the cleavage site (Lys35-Lys36) constitutes an exposed and flexible region of the GSTB1-1 G-site. By sequentially using a benzamidine-affinity chromatography and GSH-affinity column, a proteolyzed form of GSTB1-1 (23/20 kDa), in which only one subunit has been cleaved has been purified and characterized. Gel filtration, sequence analysis of subunits separated by HPLC, and CD experiments indicate that the 23/20-kDa GSTB1-1 form is a dimer and maintains its secondary structure. In addition, kinetic determinations reveal that the proteolytic cleavage of one polypeptide chain inactivates one active site but does not influence the catalytic efficiency of the second one. Previous refolding studies on GSTB1-1 have shown that the formation of a correct dimer precedes the recovery of the full activity of the enzyme, indicating that the dimeric structure is essential for catalytic activity of GSTB1-1. Thus, although GSTB1-1 active sites are catalytically independent and, probably, mainly located on each monomer, interactions deriving from the dimeric arrangement of the molecule appear essential for maintaining each active site in a fully active conformation. The catalytic independence of the two active sites, as well as the importance of dimeric structure for catalytic activity, has already been established for other GSTs. Thus, despite the very low sequence identity and kinetic differences between bacterial and other distant members of the GST superfamily, the results reported here indicate that important properties of the GST active site are conserved.
...
PMID:Purification and characterization of a heterodimeric 23/20-kDa proteolytic fragment of bacterial glutathione transferase B1-1. 864 8


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>

---