OBJECTIVETo construct the vectors of human glutathione S-transferase A1 (GSTA1), P1 (GSTP1), T1(GSTT1) genes and express in Escherichia coli (E. coli).

METHODSHuman GSTA1, GSTP1 and GSTT1 gene whole length cDNAs were amplified by RT-PCR and then subcloned into pET-28a(+) vectors. The proteins were expressed in E. coli BL21(DE3). After purified by Ni2+ affinity chromatography, the enzymatic activities of GSTs were measured with 1-chloro-2,4 -dinitrobenzene (CDNB) as substrate.

RESULTSThe correct GSTA1, GSTP1 and GSTT1 genes were cloned. And soluble GSTA1, GSTT1, GSTP1 proteins were expressed in E.coli. After purification, GSTA1, GSTT1 and GSTP1 showed good enzymatic activities, which were 17.55, 0.02, 18.75 μmol·min-1·mg-1, respectively.

CONCLUSIONThe expression plasmids for GSTA1, GSTT1 and GSTP1 have been constructed and the recombinant proteins are expressed successfully.

DNA, Complementary ; genetics ; Escherichia coli ; genetics ; Genetic Vectors ; Glutathione S-Transferase pi ; biosynthesis ; genetics ; Glutathione Transferase ; biosynthesis ; genetics ; Humans ; Recombinant Proteins ; biosynthesis ; Reverse Transcriptase Polymerase Chain Reaction

Recombinant proteins were expressed as fusions with the phagemid system of pHEN-KM13 and the characteristics and activities of the fusion proteins displayed on the surface of filamentous phagintain the were studiedon abilty. The altered titer of rescued phages from the phagemid system after trypsin treatment indicated the relative quantity of the phages displaying fusion proteins. The rescue phages displayed foreign proteins could keep the bacterial infection ability, while the bald phage without foreign protein displayed on its surface was sensitive to trypsin treatment and lost the bacterial infection ability. To determine the upper limit for filamentous phage display, four recombinant proteins, glutathione-S-transferase and glutathione-S-transferase fused with three various size peptide linkers, were fused to N terminus of capsid protein gp3 and rescued by helper phage KM13. The rescued phages which displayed fused protein with the size of 40kD or less maintain the infection ability. To assay the activity of the phage displayed protein, the known small molecule probe was used in the interaction study with protein incorporated on phage surface. Results showed that the glutathione-S-transferase on phage surface still bound to glutathione specifically. It indicated that the glutathione-S-transferase displayed on phage surface was correctly folded and functionally active. The results demonstrated that it was feasible to use small molecule probes to interact with the protein displayed on phage surface. In turn, the method described here also demonstrated that phage display system could be utilized to investigate the interactions between protein and small molecules.
Glutathione ; genetics ; metabolism ; Glutathione Transferase ; biosynthesis ; genetics ; Helper Viruses ; genetics ; metabolism ; Inovirus ; genetics ; metabolism ; Peptide Library ; Protein Binding ; Protein Interaction Domains and Motifs ; genetics ; Recombinant Fusion Proteins ; biosynthesis ; genetics

The aim of the study is to obtain an efficient expression of recombinant ubiquitin-like specific protease 1 (Ulp1) by gene engineering. We cloned the Ulp1p, active fragment (403 aa-621 aa) of Ulp1, from Saccharomyces cerevisia, and subcloned into pGEX/Rosetta (DE3) to form an expression plasmid, pGEX-Ulp1p-His6. In order to enhance the solubility of GST-Ulp1p-His6, we purified the fusion protein GST-Ulp1p-His6 by either glutathione S-transferase agarose or Ni-NTA resin chromatography, the purity was up to 98%. We utilized the protein to cleave the SUMO fusions, and the specific activity of GST-Ulp1p-His6 was 1.375 x 10(4) U/mg. This study showed that the recombinant protein GST-Ulp1p-His6 displayed high specificity and activity.
Cloning, Molecular ; Cysteine Endopeptidases ; biosynthesis ; genetics ; Escherichia coli ; genetics ; metabolism ; Fungal Proteins ; biosynthesis ; genetics ; Glutathione Transferase ; biosynthesis ; genetics ; Recombinant Fusion Proteins ; biosynthesis ; genetics ; Saccharomyces cerevisiae ; enzymology ; Solubility

OBJECTIVETo detect expression of p-glycoprotein (P-gp), multidrug resistance-associated protein (MRP), and glutathione S-transferase (GST-pi), and to evaluate its clinical significance in neuroblastoma (NB).

METHODSSP immunohistochemical technique was used to investigate expression of P-gp, MRP, and GST-pi in 70 cases of NB.

RESULTSThe frequency of expression of P-gp, MRP, and GST-pi was 61.4%, 38.6%, and 51.4%, respectively. The coexpression rate of P-gp and MRP, P-gp and GST-pi, MRP and GST-pi, P-gp, MRP and GST-pi was 32.9%, 35.7%, 27.1%, and 24.3%, respectively. Significant positive correlation was observed between P-gp and MRP expression (P = 0.001), and between MRP and GST-pi expression (P = 0.012), but no correlation was found between P-gp and GST-pi expression. The expression of P-gp and MRP was higher in tumors from patients over 1 year old compared with those less than 1 year old at diagnosis (P = 0.01, 0.018, respectively). MRP expression was higher in tumors from the metastatic than the non metastatic groups (P = 0.015). All tested proteins showed significant relationship to the differentiation of the tumor (P = 0.006, 0.000, 0.019, respectively), but no correlation was found to the stage of NB or sex of the patients. MRP expression was significantly related to the reduction of both median survival time and the two-year cumulative survival (P = 0.02). In contrast, P-gp and GST-pi expression had no correlation with survival.

CONCLUSIONSThe intrinsic multidrug resistance of NB involves the combined effects of P-gp, MRP, and GST-pi. MRP expression may be an important parameter in predicting the prognosis of patients with NB.

ATP-Binding Cassette, Sub-Family B, Member 1 ; biosynthesis ; Adolescent ; Child ; Child, Preschool ; Female ; Gene Expression ; Glutathione S-Transferase pi ; Glutathione Transferase ; biosynthesis ; Humans ; Immunohistochemistry ; Infant ; Isoenzymes ; biosynthesis ; Male ; Multidrug Resistance-Associated Proteins ; biosynthesis ; Neuroblastoma ; metabolism ; mortality ; Survival Rate

Animals ; Glutathione Transferase ; biosynthesis ; Liver Neoplasms, Experimental ; metabolism ; Male ; Rats ; Rats, Sprague-Dawley

Glutathione (GSH) plays an important role in the responses of microorganisms to the environmental stimulation and stress. The effect of H2O2 stress under different fermentation time and H2O2 concentration as well as continuous stress on GSH fermentation of Candida utilis were investigated in this paper. It was found that low concentration of H202 accelerated GSH production. When treated by low concentration of H2O2 (36 mmol/L), the final concentration of GSH reached 922 mg/L and the intracellular GSH content reached 1.64%, which increased by 7% and 35% than the controls, respectively.
Candida ; metabolism ; physiology ; Glutathione ; biosynthesis ; Hydrogen Peroxide ; pharmacology ; Stress, Physiological ; physiology

The prediction accuracy and generalization of GSH fermentation process modeling are often deteriorated by noise existing in the corresponding experimental data. In order to avoid this problem, we present a novel RBF neural network modeling approach based on entropy criterion. It considers the whole distribution structure of the training data set in the parameter learning process compared with the traditional MSE-criterion based parameter learning, and thus effectively avoids the weak generalization and over-learning. Then the proposed approach is applied to the GSH fermentation process modeling. Our results demonstrate that this proposed method has better prediction accuracy, generalization and robustness such that it offers a potential application merit for the GSH fermentation process modeling.
Candida ; growth & development ; metabolism ; Entropy ; Fermentation ; Glutathione ; biosynthesis ; Neural Networks (Computer)

Heparinase III is an enzyme that specifically cleaves certain sequences of heparan sulfate. Previous reports showed that this enzyme expressed in Escherichia coli was highly prone to aggregation in inclusion bodies and lacks detectable biological activity. In this paper, we fused a glutathione-S-transferase (GST) tag to the N-terminus of heparinase III gene and expressed the fusion protein in Escherichia coli to develop an expression system of soluble heparinase III. As a result, approximately 80% of the fusion protein was soluble. The protein was then purified to near homogeneity via one-step affinity chromatography. A 199.4-fold purification was achieved and the purified enzyme had a specific activity of 101.7 IU/mg protein. This represented 32.3% recovery of the total activity of recombinant GST-heparinase III. The maximum enzyme production was achieved when bacteria were induced with 0.5 mmol/L isopropyl-beta-D-thiogalactoside at 15 degrees C for 12 h. The enzyme showed maximum activity at 30 degrees C and pH 7.5. And the enzyme activity was stimulated by 1 mmol/L Ca2+ and 150 mmol/L NaCl.
Escherichia coli ; genetics ; metabolism ; Flavobacterium ; enzymology ; genetics ; growth & development ; Glutathione Transferase ; biosynthesis ; genetics ; Heparin Lyase ; biosynthesis ; genetics ; isolation & purification ; Recombinant Fusion Proteins ; biosynthesis ; genetics ; isolation & purification

OBJECTIVETo investigate the role of multidrug resistant protein 2 (MRP2) and glutathione (GSH) cotransport system in hepatic arsenic metabolism in rats.

METHODSThirty healthy Wistar rats were divided randomizedly into five groups. The first group was the control group and the rats in this group were administered with normal saline. In the second, third and fourth group the rats were administered with 4, 10 and 20 mg As(+)3/kg BW of sodium arsenite respectively every other day for two weeks. The fifth group was the benzene-soluble organics (BSO) intervention group and in this group the rats were administered with 2 mmol/kg BW BSO intraperitoneally every day three days before the end of the experiment. The other treatment was the same as in other groups. All rats were sacrificed two weeks after the treatments. Arsenic contents in bile, liver and blood were detected by atomic absorption spectroscopy (AAS), and the expression of MRP2 in the membrane of hepatocyte was determined by Western-blot analysis.

RESULTSThe level of total arsenic (including organic arsenic and inorganic arsenic) in bile, liver and blood in all three different dose groups was higher than those in the control groups (P < 0.05). Arsenic levels of bile and liver were increased with intragastric arsenic dose. Blood arsenic levels were not significantly different in three different dose groups. Expression of hepatic MRP2 was increased with intragastric arsenic concentration. A positive correlation between biliary arsenic concentration and MRP2 levels was found in liver (r = 0.986, P < 0.05). For the rats pretreated with BSO, the biliary arsenic was significantly higher than that in the control group but lower than that in the high dose group; the liver and blood arsenic was higher than that in the control group and in the high dose group. Expression of MRP2 pretreated with BSO was decreased.

CONCLUSIONSodium arsenite can induce expression of MRP2 and the up-regulation of MRP2 may play an important role in the bile secretion of arsenite and its metabolites. The function of MRP2 for transportation of arsenic and its metabolites is associated with the intracellular GSH level. BSO inhibits the synthesis of GSH, which weakens the function of the MRP2-GSH cotransport system and makes the liver arsenic increased.

Animals ; Arsenic ; pharmacokinetics ; Arsenic Poisoning ; metabolism ; Bile ; metabolism ; Female ; Glutathione ; biosynthesis ; Liver ; metabolism ; Male ; Membrane Transport Proteins ; biosynthesis ; Multidrug Resistance-Associated Proteins ; biosynthesis ; Random Allocation ; Rats ; Up-Regulation

OBJECTIVETo explore the correlation of chemotherapy efficacy in tongue squamous cell carcinoma(SCC) with expression level of P-glycoprotein(Pgp), multidrug resistance-associated protein (MRP), lung resistance-related protein (LRP), glutathiones-tranferase (GST-pi), DNA topo-isomerase II alpha (Topo II alpha).

METHODSThe expression patterns of Pgp, MRP, LRP, GST-pi and Topo II alpha in 40 patients (pre and post-chemotherapy, respectively) with tongue SCC were examined by immunohistochemically labelled streptavidin bioein method (LsAB).

RESULTSThe expression ratios of Pgp, MRP, LRP, GST-pi and Topo II alpha in pre-chemotherapy cases were 47.5%, 50%, 35%, 45%, 82.5%, respectively. No relations between expression of Pgp, MRP, LRP, GST-pi, Topo II alpha and clinic indexes were established (P > 0.05). Expression ratios of Pgp, MRP in post-chemotherapy cases were higher than that in pre-chemotherapy cases (P < 0.05). Expression of Pgp and MRP showed relevance with drug resistance (P < 0.05). The co-expression was common, the ratios of co-expression of Pgp, MRP, GST-pi and MRP, GST-pi in chemotherapy non-responders were 40% and 50%, respectively, but 0 in responders.

CONCLUSIONThe intrinsic multidrug resistance of tongue SCC is relevant to the effects of Pgp, MRP, GST-pi.

ATP-Binding Cassette, Sub-Family B, Member 1 ; biosynthesis ; genetics ; Adult ; Antigens, Neoplasm ; Carcinoma, Squamous Cell ; metabolism ; DNA Topoisomerases, Type II ; biosynthesis ; genetics ; DNA-Binding Proteins ; Female ; Glutathione S-Transferase pi ; Glutathione Transferase ; biosynthesis ; genetics ; Humans ; Isoenzymes ; biosynthesis ; genetics ; Male ; Middle Aged ; Multidrug Resistance-Associated Proteins ; biosynthesis ; genetics ; Neoplasm Proteins ; biosynthesis ; genetics ; Random Allocation ; Tongue Neoplasms ; metabolism ; Vault Ribonucleoprotein Particles ; biosynthesis ; genetics