scholarly journals Localization of [gamma]-Glutamylcysteine Synthetase and Glutathione Synthetase Activity in Maize Seedlings

1993 ◽  
Vol 101 (2) ◽  
pp. 561-566 ◽  
Author(s):  
A. Ruegsegger ◽  
C. Brunold
Keyword(s):  
Glutathione Synthetase ◽  
Synthetase Activity ◽  
Maize Seedlings ◽  
Glutamylcysteine Synthetase

scholarly journals Glutathione replenishment capacity is lower in isolated perivenous than in periportal hepatocytes

1988 ◽  
Vol 254 (2) ◽  
pp. 411-417 ◽  
Author(s):  
Y Kera ◽  
K E Penttilä ◽  
K O Lindros
Keyword(s):  
Glutathione Synthetase ◽  
Synthetase Activity ◽  
Gamma Glutamyl Transpeptidase ◽  
Zonal Distribution ◽  
Significant Difference ◽  
Glutamylcysteine Synthetase ◽  
Gsh Metabolism ◽  
Collagenase Perfusion ◽  
Sulphur Amino Acids ◽  
Glutamyl Transpeptidase

The zonal distribution of GSH metabolism was investigated by comparing hepatocytes obtained from the periportal (zone 1) or perivenous (zone 3) region by digitonin/collagenase perfusion. Freshly isolated periportal and perivenous cells had similar viability (dye exclusion, lactate dehydrogenase leakage and ATP content) and GSH content (2.4 and 2.7 mumol/g respectively). During incubation, periportal cells slowly accumulated GSH (0.35 mumol/h per g), whereas in perivenous cells a decrease occurred (-0.14 mumol/h per g). Also, in the presence of either L-methionine or L-cysteine (0.5 mM) periportal hepatocytes accumulated GSH much faster (3.5 mumol/h per g) than did perivenous cells (1.9 mumol/h per g). These periportal-perivenous differences were also found in cells from fasted rats. Efflux of GSH was faster from perivenous cells than from periportal cells, but this difference only explained 10-20% of the periportal-perivenous difference in accumulation. Furthermore, periportal cells accumulated GSH to a plateau 26-40% higher than in perivenous cells. There was no significant difference in gamma-glutamylcysteine synthetase or glutathione synthetase activity between the periportal and perivenous cell preparations. The periportal-perivenous difference in GSH accumulation was unaffected by inhibition of gamma-glutamyl transpeptidase or by 5 mM-glutamate or -glutamine, but was slightly diminished by 2 mM-L-methionine. This suggests differences between periportal and perivenous cells in their metabolism and/or transport of (sulphur) amino acids. Our results suggest that a lower GSH replenishment capacity of the hepatocytes from the perivenous region may contribute to the greater vulnerability of this region to xenobiotic damage.

scholarly journals Assay, purification, properties and mechanism of action of γ-glutamylcysteine synthetase from the liver of the rat and Xenopus laevis

1973 ◽  
Vol 133 (4) ◽  
pp. 667-678 ◽  
Author(s):  
J. S. Davis ◽  
J. B. Balinsky ◽  
J. S. Harington ◽  
J. B. Shepherd
Keyword(s):  
Xenopus Laevis ◽  
Rat Liver ◽  
Gel Filtration ◽  
Deae Cellulose ◽  
Glutathione Synthetase ◽  
Synthetase Activity ◽  
Protamine Sulphate ◽  
Ping Pong ◽  
Glutamylcysteine Synthetase ◽  
Sequential Mechanism

1. An improved radioassay for glutathione synthetase and γ-glutamylcysteine synthetase was developed. 2. Xenopus laevis liver γ-glutamylcysteine synthetase was purified 324-fold by saline–bicarbonate extraction, protamine sulphate precipitation, CM-cellulose and DEAE-cellulose column chromatography, and gel filtration. 3. Rat liver γ-glutamylcysteine synthetase was purified 11400-fold by a procedure similar to that employed for the Xenopus laevis enzyme. 4. Rat liver γ-glutamylcysteine synthetase activity was inhibited by GSH and activated by glycine. These effects, which were not found in the enzyme from Xenopus laevis, may have a regulatory significance. 5. Isotope-exchange experiments revealed fundamental differences in the partial reactions catalysed by the rat and Xenopus laevis synthetases. The enzyme from Xenopus laevis appears to follow a Bi Bi Uni Uni Ping Pong mechanism, with glutamyl–enzyme as intermediate before the addition of cysteine and the release of γ-glutamylcysteine. The results for the rat liver enzyme are consistent with a Tri Tri sequential mechanism.

scholarly journals Surgical trauma decreases glutathione synthetic capacity in human skeletal muscle tissue

1998 ◽  
Vol 275 (2) ◽  
pp. E359-E365 ◽  
Author(s):  
Jia-Li Luo ◽  
Folke Hammarqvist ◽  
Kerstin Andersson ◽  
Jan Wernerman
Keyword(s):  
Skeletal Muscle ◽  
Muscle Tissue ◽  
Redox Status ◽  
Skeletal Muscle Tissue ◽  
Surgical Trauma ◽  
Synthetase Activity ◽  
Glutamylcysteine Synthetase ◽  
Gsh Metabolism ◽  
Synthetic Capacity ◽  
Femoris Muscle

To gain insight into cellular metabolism underlying the glutathione (GSH) alterations induced by surgical trauma, we assessed postoperative skeletal muscle GSH metabolism and its redox status in 10 patients undergoing elective abdominal surgery. Muscle biopsy specimens were taken from the quadriceps femoris muscle before and at 24 and 72 h after surgery. GSH concentrations decreased by 40% at 24 h postoperatively compared with the paired preoperative values ( P < 0.001) and remained low at 72 h ( P < 0.01). The concentration of GSH disulfide (GSSG) did not significantly change throughout the study period, whereas the total GSH (as GSH equivalent) concentration decreased after surgery. Of the GSH constituent amino acids, the concentration of cysteine remained unchanged throughout the study period (from 28.2 ± 10.1 preoperatively to 29.4 ± 13.9 at 24 h postoperatively and to 28.3 ± 15.6 μmol/kg wet wt at 72 h postoperatively). Despite a reduction in glutamate concentration by 40% 24 h after surgery, no correlation was established between GSH and glutamate concentrations postoperatively. Activity of γ-glutamylcysteine synthetase did not change significantly after surgery, whereas GSH synthetase activity decreased postoperatively (from 66.4 ± 19.1 preoperatively to 41.0 ± 10.5 24 h postoperatively, P < 0.01, and to 46.0 ± 11.7 μU/mg protein 72 h postoperatively, P < 0.05). The decrease of GSH was correlated to the reduced GSH synthetase activity seen at 24 h postoperatively. These results indicate that the skeletal muscle GSH pool is diminished in patients after surgical trauma. The depletion of the GSH pool is associated with a decreased activity of GSH synthetase, indicating a decreased GSH synthetic capacity in skeletal muscle tissue.

scholarly journals Effect of chilling and acclimation on the activity of glutamine synthetase isoforms in maize seedlings

2007 ◽  
Vol 59 (3) ◽  
pp. 177-185 ◽  
Author(s):  
Ana Simonovic ◽  
M.D. Anderson
Keyword(s):  
Oxidative Stress ◽  
Glutamine Synthetase ◽  
Synthetase Activity ◽  
Glutamine Synthetase Activity ◽  
Maize Seedlings ◽  
Oxidative Inactivation ◽  
Etiolated Plants

Effects of chilling and acclimation on the activity of cytosolic (GS1) and plastidic (GS2) isoforms of glutamine synthetase (E.C. 6.3.1.2) were studied in chilling-sensitive and acclimation-responsive maize inbred G50. Glutamine synthetase activity in mesocotyls and roots of chilled (7 d/4?C) and rewarmed (1 d/27?C) etiolated plants was "1/3 that of controls. In coleoptiles+leaves of light-grown plants, GS1 was reduced to 75%, and GS2 to 50%. Acclimation (3 d/14?C) increased GS activity and alleviated the effects of chilling. Exposure to H2O2 or menadione also reduced GS activity. Since chilling causes oxidative stress in maize, acclimation probably preserves GS activity by protecting GS from oxidative inactivation. .

scholarly journals Three cases of hereditary nonspherocytic hemolytic anemia associated with red blood cell glutathione deficiency

Blood ◽  
1996 ◽  
Vol 87 (5) ◽  
pp. 2071-2074 ◽  
Author(s):  
A Hirono ◽  
H Iyori ◽  
I Sekine ◽  
J Ueyama ◽  
H Chiba ◽  
...  
Keyword(s):  
Blood Cell ◽  
Hemolytic Anemia ◽  
Red Blood Cell ◽  
Japanese Patients ◽  
Glutathione Synthetase ◽  
Synthetase Activity ◽  
Glutathione S Transferase ◽  
Mild Deficiency ◽  
Glutathione Deficiency ◽  
Generalized Type

Abstract Three unrelated Japanese patients with chronic nonspherocytic hemolytic anemia wer found to have marked deficiency of red blood cell (RBC) reduced glutathoine (GSH) (4.4%, 13.1%, and 6.9% of normal, respectively). A panel of RBC enzyme assays showed that one patient had decreased glutathione synthetase activity and the other two were moderately deficient in gamma-glutamylcystine synthetase. Some family members of each patient showed mild deficiency of the respective enzymes. RBCs of these patients also showed a decreased level of glutathione-S-transferase as in previously described GSH-deficient cases. Hemolytic anemia was their only manifestation, and neither 5- oxoprolinemia nor 5-oxoprolinuria, which are usually associated with to generalized type of glutathione synthetase deficiency, was noted in our patients.

scholarly journals Molecular Analysis of the Pathway for the Synthesis of Thiol Tripeptides in the Model Legume Lotus japonicus

2003 ◽  
Vol 16 (11) ◽  
pp. 1039-1046 ◽  
Author(s):  
Manuel A. Matamoros ◽  
Maria R. Clemente ◽  
Shusei Sato ◽  
Erika Asamizu ◽  
Satoshi Tabata ◽  
...  
Keyword(s):  
Lotus Japonicus ◽  
Regulatory Elements ◽  
Chromosome 1 ◽  
Glutathione Synthetase ◽  
Promoter Regions ◽  
Model Legume ◽  
Cis Acting ◽  
Glutamylcysteine Synthetase ◽  
Exon 1 ◽  
Legume Symbiosis

The thiol tripeptides, glutathione (GSH) and homoglu-tathione (hGSH), perform multiple roles in legumes, including protection against toxicity of free radicals and heavy metals. The three genes involved in the synthesis of GSH and hGSH in the model legume, Lotus japonicus, have been fully characterized and appear to be present as single copies in the genome. The γ-glutamylcysteine synthetase (γecs) gene was mapped on the long arm of chromosome 4 (70.0 centimorgans [cM]) and consists of 15 exons, whereas the glutathione synthetase (gshs) and homoglutathione synthetase (hgshs) genes were mapped on the long arm of chromosome 1 (81.3 cM) and found to be arranged in tandem with a separation of approximately 8 kb. Both genes consist of 12 exons of exactly the same size (except exon 1, which is similar). Two types of transcripts were detected for the gshs gene, which putatively encode proteins localized in the plastids and cytosol. Promoter regions contain cis-acting regulatory elements that may be involved in the plant's response to light, hormones, and stress. Determination of transcript levels, enzyme activities, and thiol contents in nodules, roots, and leaves revealed that γecs and hgshs are expressed in all three plant organs, whereas gshs is significantly functional only in nodules. This strongly suggests an important role of GSH in the rhizobia-legume symbiosis.

scholarly journals apd1  +, a Gene Required for Red Pigment Formation in ade6 Mutants of Schizosaccharomyces pombe, Encodes an Enzyme Required for Glutathione Biosynthesis: A Role for Glutathione and a Glutathione-Conjugate Pump

Genetics ◽  
1997 ◽  
Vol 145 (1) ◽  
pp. 75-83 ◽  
Author(s):  
Biswendu Chaudhuri ◽  
Susham Ingavale ◽  
Anand K Bachhawat
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Schizosaccharomyces Pombe ◽  
Biosynthetic Pathway ◽  
Glutathione Synthetase ◽  
Red Pigment ◽  
Genetic Investigation ◽  
Pigment Formation ◽  
Glutathione Conjugate ◽  
Glutathione Biosynthesis ◽  
Glutamylcysteine Synthetase

Mutants in the adenine biosynthetic pathway of yeasts (ade1 and ade2 of Saccharomyces cerevisiae, ade6 and ade7 of Schizosaccharomyces pombe) accumulate an intense red pigment in their vacuoles when grown under adenine-limiting conditions. The precise events that determine the formation of the pigment are however, still unknown. We have begun a genetic investigation into the nature and cause of pigmentation of ade6 mutants of S. pombe and have discovered that one of these pigmentation defective mutants, apd1 (adenine pigmentation defective), is a strict glutathione auxotroph. The gene apd1  + was found to encode the first enzyme in glutathione biosynthesis, γ-glutamylcysteine synthetase, gcs1  +. This gene when expressed in the mutant could confer both glutathione prototrophy and the characteristic red pigmentation, and disruption of the gene led to a loss in both phenotypes. Supplementation of glutathione in the medium, however, could only restore growth but not the pigmentation because the cells were unable to achieve sufficient intracellular levels of glutathione. Disruption of the second enzyme in glutathione biosynthesis, glutathione synthetase, gsh2  +, also led to glutathione auxotrophy, but only a partial defect in pigment formation. A reevaluation of the major amino acids previously reported to be present in the pigment indicated that the pigment is probably a glutathione conjugate. The ability of vanadate to inhibit pigment formation indicated that the conjugate was transported into the vacuole through a glutathione-conjugate pump. This was further confirmed using strains of S. cerevisiae bearing disruptions in the recently identified glutathione-conjugate pump, YCF1, where a significant reduction in pigment formation was observed. The pump of S. pombe is distinct from the previously identified vacuolar pump, hmt1p, for transporting cadystin peptides into vacuoles of S. pombe.

Sign in / Sign up

Export Citation Format

Share Document