IPTG Concentration Research Articles

Recombinant Production of Human Interleukin 6 in Escherichia coli

In this study, we compared basic expression approaches for the efficient expression of bioactive recombinant human interleukin-6 (IL6), as an example for a difficult-to-express protein. We tested these approaches in a laboratory scale in order to pioneer the commercial production of this protein in Escherichia coli (E. coli). Among the various strategies, which were tested under Research and Development (R&D) conditions, aggregation-prone IL6 was solubilized most effectively by co-expressing cytoplasmic chaperones. Expression of a Glutathion-S-Transferase (GST) fusion protein was not efficient to increase IL6 solubility. Alteration of the cultivation temperature significantly increased the solubility in both cases, whereas reduced concentrations of IPTG to induce expression of the T7lac-promotor only had a positive effect on chaperone-assisted expression. The biological activity was comparable to that of commercial IL6. Targeting the expressed protein to an oxidizing environment was not effective in the generation of soluble IL6. Taken together, the presence of chaperones and a lowered cultivation temperature seem effective to isolate large quantities of soluble IL6. This approach led to in vivo soluble, functional protein fractions and reduces purification and refolding requirements caused by downstream purification procedures. The final yield of soluble recombinant protein averaged approximately 2.6 mg IL6/liter of cell culture. These findings might be beneficial for the development of the large-scale production of IL6 under the conditions of current good manufacturing practice (cGMP).

Modification in media composition to obtain secretory production of STxB-based vaccines using Escherichia coli

Shiga toxin B-subunit (STxB) from Shigella dysenteriae targets in vivo antigen to cancer cells, dendritic cells (DC) and B cells, which preferentially express the globotriaosylceramide (Gb3) receptor. This pivotal role has encouraged scientists to investigate fusing STxB with other clinical antigens. Due to the challenges of obtaining a functional soluble form of the recombinant STxB, such as formation of inclusion bodies during protein expression, scientists tend to combine STxB with vaccine candidates rather than using their genetically fused forms. In this work, we fused HPV16 E7 as a vaccine candidate to the recombinantly-produced STxB. To minimize the formation of inclusion bodies, we investigated a number of conditions during the expression procedure. Then various strategies were used in order to obtain high yield of soluble recombinant protein from E. coli which included the use of different host strains, reduction of cultivation temperature, as well as using different concentrations of IPTG and different additives (Glycin, Triton X-100, ZnCl(2)). Our study demonstrated the importance of optimizing incubation parameters for recombinant protein expression in E. coli; also showed that the secretion production can be achieved over the course of a few hours when using additives such as glycine and Triton X-100. Interestingly, it was shown that when the culture mediums were supplemented by additives, there was an inverse ratio between time of induction (TOI) and the level of secreted protein at lower temperatures. This study determines the optimal conditions for high yield soluble E7-STxB expression and subsequently facilitates reaching a functionally soluble form of STxB-based vaccines, which can be considered as a potent vaccine candidate for cervical cancer.

High-Yield Soluble Expression and Simple Purification of the Antimicrobial Peptide OG2 Using the Intein System inEscherichia coli

OG2 is a modified antimicrobial peptide, that is, derived from the frog peptide Palustrin-OG1. It has high antimicrobial activity and low cytotoxicity, and it is therefore promising as a therapeutic agent. Both prokaryotic (Escherichia coli) and eukaryotic (Pichia pastoris) production host systems were used to produce OG2 in our previous study; however, it was difficult to achieve high expression yields and efficient purification. In this study, we achieved high-yield OG2 expression using the intein fusion system. The optimized OG2 gene was cloned into the pTWIN1 vector to generate pTWIN-OG2-intein2 (C-terminal fusion vector) and pTWIN-intein1-OG2 (N-terminal fusion vector). Nearly 70% of the expressed OG2-intein2 was soluble after the IPTG concentration and induction temperature were decreased, whereas only 42% of the expressed of intein1-OG2 was soluble. Up to 75 mg of OG2-intein2 was obtained from a 1 l culture, and 85% of the protein was cleaved by 100 mM DTT. Intein1-OG2 was less amenable to cleavage due to the inhibition of cleavage by the N-terminal amino acid of OG2. The purified OG2 exhibited strong antimicrobial activity against E. coli K88. The intein system is the best currently available system for the cost-effective production of OG2.

Optimizing expression of recombinant jasmonate ZIM-domain protein from Salvia miltiorrhiza

Accumulation of tanshinton in Salvia miltiorrhiza are enhanced by exogenous application of jasmonates. The core JA signaling module COI1/JAZ/MYC2 play a central role on control of downstream gene expression in the JA pathway. To obtained the antibody of SmJAZ, SmJAZ recombinant protein was expressed in Escherichia coli and optimal expression was performed. The full-length SmJAZ1 ORF was sub-cloned in a prokaryotic expression vector pET32a. The recombinant fusion protein had high expression level in BL21 (DE3) strain of E. coli, and SDS-PAGE analysis showed its molecular weight was about 24 kDa. The induction of E. coli [pET32-JAZ1] in different temperature, induction time, IPTG concentrations and IPTG adding time of E. coli were performed. The induction time and the induction temperature are positively related trends with SmJAZ1 protein expression, and IPTG concentration had no significant impact in protein expression, whereas IPTG adding time had significant impact on protein expression. Shaking the culture at 30 degrees C until the A600 is approximately 0.9 (2 h in LB), and add IPTG to a final concentration of 0.1 mmol x L(-1), and then the optimal expression of SmJAZ1 recombinant protein were accumulated after the induction time of 20 h.

Cloning, Expression, Purification, and Characterization of an Organophosphate-Degrading Enzyme in Escherichia Coli

OpdA is one of organic phosphorus degradation enzyme gene from Agrobacterium radiobacter that may be the most promising targets for the digestion of digestion. In this study, we describe for the cloning and expression in Escherichia coli (E. coli) of plasmid pET28b-opdA, followed by purification by NTA-Ni2+ agarose affinity chromatography. Protein expression and purification were evaluated by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE).The Results showed that the optimal value of inoculum OD600 before induction, inducing time, final IPTG concentration and inducing temperature respectively were 0.5,5h,1 mmol/L,37°C. We obtained the concentration of renatured protein was 18.312mg / L. The Km was 4.26μmol/L at 37 °C, and the maximum reaction velocity (Vmax) was 3.2669μmol/L • min.

Optimization of Dengue-3 recombinant NS1 protein expression in E. coli and in vitro refolding for diagnostic applications

Dengue non-structural protein (NS1) is known to be protective antigen and also has immense application for serodiagnosis. Several serodiagnostic assays available for dengue viral infection are dependent on tissue culture-grown viral proteins. This task is unsafe, laborious, more expensive that makes it unsuitable for routine large-scale production. Although bacterial expression is relatively simple and easy for recombinant protein expression, it is more challenging to make NS1 protein with native structural and immunological features using bacterial expression system. We have successfully developed a method leading to the purification and refolding of recombinant dengue virus type 3 (DENV3) NS1. The gene encoding NS1 was amplified and cloned in pET28a (+) vector. In order to increase the purity of the recombinant NS1, the transgene was engineered to carry 6× Histidine tags at both N and C-terminal ends. The recombinant construct (pETNS1) was transformed into E. coli Rosetta-gami cells and the expression conditions viz IPTG concentration, media type, temperature, and harvest time were optimized. The size of the expressed protein was found to be ~45 kDa and the authenticity of the expressed protein was confirmed using anti-His and anti-NS1 monoclonal antibodies. The NS1 protein was purified under denaturing conditions, to attain the native conformation, NS1 protein was in vitro refolded and dialyzed. The refolded NS1 protein was detected by commercial Immuno chromatographic strip and NS1 specific monoclonal antibodies. IgM antibody capture ELISA was performed using refolded recombinant NS1 protein which recognized the IgM antibodies in dengue-positive samples of acute phase of infection. Our result suggests that rNS1 protein has immense diagnostic potential and can be used in developing point of care diagnostic assays.

IPTG limitation avoids metabolic burden and acetic acid accumulation in induced fed-batch cultures of Escherichia coli M15 under glucose limiting conditions

The most common strategy to produce recombinant proteins using Escherichia coli as expression vector is fed-batch culture, since high cell density cultures strategies have successfully been applied. Several methodologies to limit the specific growth rate in order to control E. coli metabolism have been defined, demonstrating that cultures can be grown under glucose limitation up to high cell densities without accumulation of acetic acid. However, under induction conditions it has been observed that E. coli metabolism is reorganized again and leads to acetic acid accumulation, causing inhibition of cell growth and decreasing protein expression efficiency.We propose a double limitation strategy (glucose and IPTG) for E. coli fed-batch cultures to avoid the deregulation of the metabolism in the induction phase. Reducing the concentration of IPTG while keeping glucose growth limitation, the accumulation of acetic acid decreased. At an IPTG concentration of 0.03mmol/g DCW no accumulation of acetic acid was observed during the induction phase, in contraposition to what has normally been observed.Although a slight reduction of protein expression rate was observed when applying this double limitation strategy, the bioprocess volumetric productivity was enhanced due to the capability to prolong the induction phase, reaching higher levels of protein production. Another advantage of this strategy is the reduction of media cost due to the lower level of IPTG used.

Optimization of TNF-α overexpression in Escherichia coli using response surface methodology: Purification of the protein and oligomerization studies

Tumor necrosis factor-α (TNF-α) is responsible for many autoimmune disorders including rheumatoid arthritis, psoriasis, Chron’s disease, stroke, and atherosclerosis. Thus, inhibition of TNF-α is a major challenge in drug discovery. However, a sufficient amount of purified protein is needed for the in vitro screening of potential TNF-α inhibitors. In this work, induction conditions for the production of human TNF-α fusion protein in a soluble form by recombinant Escherichia coli BL21(DE3) pLysS were optimized using response surface methodology based on the central composite design. The induction conditions included cell density prior induction (OD600nm), post-induction temperature, IPTG concentration and post-induction time. Statistical analysis of the results revealed that all variables and their interactions had significant impact on production of soluble TNF-α. An 11% increase of TNF-α production was achieved after determination of the optimum induction conditions: OD600nm prior induction 0.55, a post induction temperature of 25°C, an IPTG concentration of 1mM and a post-induction time of 4h. We have also studied TNF-α oligomerization, the major property of this protein, and a Kd value of 0.26nM for protein dimerization was determined. The concentration of where protein trimerization occurred was also detected. However, we failed to determine a reliable Kd value for protein trimerization probably due to the complexibility of our model.

Characterization and optimization of ArtinM lectin expression in Escherichia coli

BackgroundArtinM is a d-mannose-specific lectin from Artocarpus integrifolia seeds that induces neutrophil migration and activation, degranulation of mast cells, acceleration of wound healing, induction of interleukin-12 production by macrophages and dendritic cells, and protective T helper 1 immune response against Leishmania major, Leishmania amazonensis and Paracoccidioides brasiliensis infections. Considering the important biological properties of ArtinM and its therapeutic applicability, this study was designed to produce high-level expression of active recombinant ArtinM (rArtinM) in Escherichia coli system.ResultsThe ArtinM coding region was inserted in pET29a(+) vector and expressed in E. coli BL21(DE3)-Codon Plus-RP. The conditions for overexpression of soluble ArtinM were optimized testing different parameters: temperatures (20, 25, 30 or 37°C) and shaking speeds (130, 200 or 220 rpm) during induction, concentrations of the induction agent IPTG (0.01-4 mM) and periods of induction (1-19 h). BL21-CodonPlus(DE3)-RP cells induced under the optimized conditions (incubation at 20°C, at a shaking speed of 130 rpm, induction with 0.4 mM IPTG for 19 h) resulted in the accumulation of large amounts of soluble rArtinM. The culture provided 22.4 mg/L of rArtinM, which activity was determined by its one-step purification through affinity chromatography on immobilized d-mannose and glycoarray analysis. Gel filtration showed that rArtinM is monomeric, contrasting with the tetrameric form of the plant native protein (jArtinM). The analysis of intact rArtinM by mass spectrometry revealed a 16,099.5 Da molecular mass, and the peptide mass fingerprint and esi-cid-ms/ms of amino acid sequences of peptides from a tryptic digest covered 41% of the total ArtinM amino acid sequence. In addition, circular dichroism and fluorescence spectroscopy of rArtinM indicated that its global fold comprises β-sheet structure.ConclusionsOverall, the optimized process to express rArtinM in E. coli provided high amounts of soluble, correctly folded and active recombinant protein, compatible with large scale production of the lectin.

Cloning and prokaryotic expression of ghrelin gene in crucian carp (Carassius auratus)

To make up the flaw that there is no available information about ghrelin gene in crucian carp. The ghrelin gene was amplified by reverse transcription-PCR (RT-PCR) using total RNA extracted from intestine of crucian carp. PCR product was cloned into the pMD®19-T vector to construct pMD®19-T-ghrlein for sequencing. Then the cDNA was subcloned into the prokaryotic expressing plasmid vector pET32a and was transformed into hostEscherichia coli strain Rosetta for expression. In this study, 490 bp fragment of ghrelinwas obtained by RT-PCR. In comparison with other fishes, the amino acid sequences ofghrelin in crucian carp showed a high similarity to that of goldfish (99%). The high expression of ghrelin gene was detected in the intestine and liver by real-time PCR. IPTG at concentrations of 0, 0.1, 0.2, 0.3, 0.5, 0.7 and 1.0 mmol/L could efficiently induce the expression of pGh-32. The result showed that the optimal concentration of IPTG was 0.3 mmol/L by SDS-polyacrylamide gel electrophoresis (SDS-PAGE). The ghrelin gene expressed as early as 1 h after IPTG induction, and reached peak levels after 3 h. Successful expression of ghrelin fusion protein in prokaryotic cell could lay a basis for further study of industrial production. Key words: Crucian carp, ghrelin, cloning, prokaryotic expression.

Optimization of an extracellular zinc-metalloprotease (SVP2) expression in Escherichia coli BL21 (DE3) using response surface methodology

In this work, SVP2 from Salinivibrio proteolyticus strain AF-2004, a zinc metalloprotease with suitable biotechnological applications, was cloned for expression at high levels in Escherichia coli with the intention of changing culture conditions to generate a stable extracellular enzyme extract. The complete ORF of SVP2 gene was heterologously expressed in E. coli BL21 (DE3) by using pQE-80L expression vector system. In initial step, the effect of seven factors include: incubation temperature, peptone and yeast extract concentration, cell density (OD600) before induction, inducer (IPTG) concentration, induction time, and Ca2+ ion concentrations on extracellular recombinant SVP2 expression and stability were investigated. The primary results revealed that the IPTG concentration, Ca2+ ion concentration and induction time are the most important effectors on protease secretion by recombinant E. coli BL21. Central composite design experiment in the following showed that the maximum protease activity (522U/ml) was achieved in 0.0089mM IPTG for 24h at 30°C, an OD600 of 2, 0.5% of peptone and yeast extract, and a Ca2+ ion concentration of 1.3mM. The results exhibited that the minimum level of IPTG concentration along with high cell density and medium level of Ca2+ with prolonged induction time provided the best culture condition for maximum extracellular production of heterologous protease SVP2 in E. coli expression system.

재조합 Escherichia coli를 이용한 gamma-Aminobutyric Acid 전환 반응 최적화

In this study, the effects of pH, temperature, IPTG concentration and substrate (MSG) concentration on gamma-aminobutyric acid (GABA) production in engineered Escherichia coli were investigated. Glutamate decarboxylase and glutamate/GABA antiporter were overexpressed in GABA aminotransferase knock-out strain for GABA production. The result of optimization study showed the GABA bioconversion was optimized at pH 3.5, <TEX>$30^{\circ}C$</TEX>, 0.5 mM IPTG, 10 g/L MSG. At this condition, 5.23 g/L of final GABA concentration of was achieved from 10 g/L of MSG, which corresponded to a GABA yield of 85.77%.

English

The human foamy virus (HFV) may pose a risk to humans as an infectious agent. The HFV transactivator Tas plays a critical role as a regulatory factor in viral replication, and potently activates gene expression via the 5&#39; LTRs (long terminal repeats) of HFV. However the anti-Tas antibody currently available can rarely be applied in the investigation and diagnosis of HFV because of its high valence. To better understand the possible role of Tas as a potential candidate for the diagnosis and understanding of the infectious mechanism of HFV, the cloning, expression, and purification of Tas are described in this report. Additionally, the preparation of a polyclonal antibody directed against Tas is described. The&nbsp;Tas&nbsp;gene was amplified from wild type HFV (pHSRV13) by PCR, subcloned into the pGEX-4T-1 expression plasmid, and then introduced into&nbsp;Escherichia coli&nbsp;BL21 (DE3) cells. To make the GST-Tas fusion protein, the recombinant expression plasmid pGEX-4T-1-Tas was induced using isopropyl-&beta;-d-thiogalactoside. Optimal levels of GST-Tas were obtained by optimizing the concentration of IPTG and the induction time. After purification, GST-Tas was used to immunize mice, after which a standard protocol was used to acquire antiserum. Western blot analysis indicated that the prepared antiserum reacted specifically to the recombinant protein when expressed in eukaryotic cells, demonstrating good antigenicity of the antiserum. The HFV Tas protein showed low homology when compared to the foamy virus Tas protein in other species, suggesting that the HFV Tas polyclonal antibody may be specific to HFV Tas. The present study sheds light on the mechanism of the transactivator function and immunogenicity of Tas. Information from this study could be used to develop antibody or antigen detection assays for the clinical detection of the HFV pathogen. Key words:&nbsp;HFV, Tas, polyclonal antibody, expression, western blot.

Cloning and expression of alkaline protease genes from two salt-tolerant alkaliphilic actinomycetes in E. coli

Cloning and expression of recombinant alkaline serine proteases from two salt tolerant alkaliphilic actinomycetes strains: OM-6 (EU710555.1) and OK-5 (HM560975) were successfully obtained in mesophilic host, Escherichia coli. The positive clones harboring protease genes were selected on the basis of restriction analysis on agarose gel. The effect of temperature and IPTG concentrations on the expression of recombinant proteases and solubilization of the expressed enzymes was assessed. SDS-PAGE revealed protease bands corresponding to 25kDa and 20kDa molecular mass representing OM-6 and OK-5 proteases, respectively. Cloning and expression of alkaline proteases from salt tolerant alkaliphilic actinomycetes would pave the way for further biochemical and molecular characterization to achieve unexplored features of the biocatalysts from extremophiles.

Optimization of Taq DNA polymerase enzyme expression in Escherichia coli

Background:In the present study, we optimized the experimental conditions using pET15b expression vector to obtain large amounts of Taq DNA polymerase.Materials and Methods:Correct framing of the gene in the expression vector pET15b and its orientation were analyzed by digestion and sequencing. Production of Taq DNA polymerase in Escherichia coli BL21 (DE3) cells was induced by incubation with different concentrations of IPTG. Optimum production occurred with the addition of 1mM IPTG for 2h. The activity of the obtained enzyme was measured by comparing the intensities of the produced DNA bands in PCR reactions.Results:Recombinant plasmid containing taq polymerase gene was confirmed by restriction digestion and DNA sequencing. Purified protein was identified by Western blotting. Optimum condition for the production of the enzyme was induction with 1mM IPTG for 23h. Addition of NP40 increased enzyme stability.Conclusion:We expressed the recombinant Taq DNA polymerase in E. coli using a T7based promoter system and obtained an active and stable enzyme.

Cloning, Expression, and Immunogenicity Analysis of the CpsE Protein from Group B Streptococcus Isolated from Tilapia (Oreochromis Niloticus)

Group B Streptococcus (GBS) is a major cause of serious bacterial infection in numerous animal species. The production of capsular polysaccharide(CPs) is vital to GBS to evade host immunity. One of the genes that required for production of CPs, cpsE, has been determined to be well conserved in capsule gene cluster (cps).This study cloned the cpsE gene from Tilapia of GBS clinical isolate (serotype Ia) and expressed this gene with aid of pET-32a(+) in Escherichia coli BL21(DE3) competent cells to obtain high levels of the recombinant protein for further study about CpsE in fish and examination of its immunogenicity. The optimization of induction conditions (IPTG concentration, temperature and time) in E.coli was accomplished and let us to perform the recombinant protein induction at 37℃ for 3h,with 0.2mM IPTG in Luria Bertani (LB) medium. At the optimal conditions, recombinant protein was expressed in an insoluble form (inclusion bodies) and accounted for approximately 23% of the total protein. Purification by affinity chromatography yielded about 480mg fusion protein per liter culture.

Evidencing the role of lactose permease in IPTG uptake by Escherichia coli in fed-batch high cell density cultures

The lac-operon and its components have been studied for decades and it is widely used as one of the common systems for recombinant protein production in Escherichia coli. However, the role of the lactose permease, encoded by the lacY gene, when using the gratuitous inducer IPTG for the overexpression of heterologous proteins, is still a matter of discussion. A lactose permease deficient strain was successfully constructed. Growing profiles and acetate production were compared with its parent strain at shake flask scale. Our results show that the lac-permease deficient strain grows slower than the parent in defined medium at shake flask scale, probably due to a downregulation of the phosphotransferase system (PTS). The distributions of IPTG in the medium and inside the cells, as well as recombinant protein production were measured by HPLC-MS and compared in substrate limiting fed-batch fermentations at different inducer concentrations. For the mutant strain, IPTG concentration in the medium depletes slower, reaching at the end of the culture higher concentration values compared with the parent strain. Final intracellular and medium concentrations of IPTG were similar for the mutant strain, while higher intracellular concentrations than in medium were found for the parent strain. Comparison of the distribution profiles of IPTG of both strains in fed-batch fermentations showed that lac-permease is crucially involved in IPTG uptake. In the absence of the transporter, apparently IPTG only diffuses, while in the presence of lac-permease, the inducer accumulates in the cytoplasm at higher rates emphasizing the significant contribution of the permease-mediated transport.

Lac operon induction in Escherichia coli: Systematic comparison of IPTG and TMG induction and influence of the transacetylase LacA

Most commonly used expression systems in bacteria are based on the Escherichia coli lac promoter. Furthermore, lac operon elements are used today in systems and synthetic biology. In the majority of the cases the gratuitous inducers IPTG or TMG are used. Here we report a systematic comparison of lac promoter induction by TMG and IPTG which focuses on the aspects inducer uptake, population heterogeneity and a potential influence of the transacetylase, LacA. We provide induction curves in E. coli LJ110 and in isogenic lacY and lacA mutant strains and we show that both inducers are substrates of the lactose permease at low inducer concentrations but can also enter cells independently of lactose permease if present at higher concentrations. Using a gfp reporter strain we compared TMG and IPTG induction at single cell level and showed that bimodal induction with IPTG occurred at approximately ten-fold lower concentrations than with TMG. Furthermore, we observed that lac operon induction is influenced by the transacetylase, LacA. By comparing two Plac-gfp reporter strains with and without a lacA deletion we could show that in the lacA(+) strain the fluorescence level decreased after few hours while the fluorescence further increased in the lacA(-) strain. The results indicate that through the activity of LacA the IPTG concentration can be reduced below an inducing threshold concentration-an influence that should be considered if low inducer amounts are used.

English

The cDNA fragment of&nbsp;a rice&nbsp;NAD-malic enzyme&nbsp;(OsNAD-ME1)&nbsp;was cloned and constructed into expression vector (pGEX-6p-3).&nbsp;OsNAD-ME1&nbsp;was successfully expressed as a GST fusion protein in&nbsp;Escherichia coli&nbsp;BL21.&nbsp;The optimal concentration of IPTG for inducement was 1&nbsp;mmol/L&nbsp;and the optimal&nbsp;culturetemperature was 30&deg;C. The fusion protein was purified by using affinity chromatography with a glutathione sepharose 4B column. After enzymatic cleavage of GST tag, the&nbsp;OsNAD-ME1&nbsp;recombinant protein was collected for studying its kinetic properties. The optimum pH and temperature for catalytic reaction&nbsp;ofOsNAD-ME1&nbsp;were pH 6.4 and 35&deg;C, respectively. The&nbsp;kcat&nbsp;value determined at pH 6.4 was&nbsp;36.38&nbsp;s-1&nbsp;and the&nbsp;Km&nbsp;values&nbsp;for NAD+&nbsp;and malate were 0.10 and 15.98mmol/L, respectively. The maximum activity of&nbsp;OsNAD-ME1&nbsp;using NADP+&nbsp;as coenzyme&nbsp;was 64.47% of that using NAD+&nbsp;as coenzyme. &nbsp; Key words:&nbsp;Enzyme activity, GST fusion protein, kinetic properties, NAD-malic enzyme,&nbsp;Oryza sativa&nbsp;L., purification.

Expression of Pseudorabies Virus (PRV) Glycoproteins gB, gC and gD using Bacterial Expression System

The Pseudorabies (PR), also called Aujeszky's disease (AD), is an infectious viral disease caused by an alpha herpes virus and has domestic and wild pigs, as well as a wide range of domestic and wild animals, as the natural host. Pseudorabies virus (PRV) virions contain several envelope glycoproteins. Among them, gB, gC and gD are regarded as the major immunogenic proteins. We expressed these glycoproteins using the bacterial expression system and analyzed recombinant proteins. Expression of glycoproteins gC and gD were observed on SDS-PAGE or Western blot analysis, but gB was not. Optimal concentration of IPTG and inducing time were determined as 1.0 mM and 4 h, respectively, for the expression of both gC and gD in E. coli. A sodium dodecyl sulfate (SDS) was the most efficient detergent in solubilizing insoluble recombinant protein.