Protein Expression and Purification Journal Impact Factor & Information

Publisher: Elsevier

Journal description

The power of modern molecular genetics to provide large quantities of proteins that were previously difficult to obtain has sparked an explosion of interest in both practical and theoretical aspects of protein purification. Protein Expression and Purification is dedicated to providing a forum for information about protein isolation based on conventional fractionation as well as techniques employing various molecular biological procedures to increase protein expression.

Current impact factor: 1.51

Impact Factor Rankings

2015 Impact Factor Available summer 2015
2013 / 2014 Impact Factor 1.508
2012 Impact Factor 1.429
2011 Impact Factor 1.587
2010 Impact Factor 1.644
2009 Impact Factor 1.563
2008 Impact Factor 1.621
2007 Impact Factor 1.94
2006 Impact Factor 1.867
2005 Impact Factor 1.553
2004 Impact Factor 1.336
2003 Impact Factor 1.47
2002 Impact Factor 1.375
2001 Impact Factor 1.497
2000 Impact Factor 1.569
1999 Impact Factor 1.416
1998 Impact Factor 1.382
1997 Impact Factor 1.341
1996 Impact Factor 1.413
1995 Impact Factor 1.497
1994 Impact Factor 1.822

Impact factor over time

Impact factor
Year

Additional details

5-year impact 1.51
Cited half-life 7.20
Immediacy index 0.38
Eigenfactor 0.01
Article influence 0.43
Website Protein Expression and Purification website
Other titles Protein expression and purification (Online), Protein expression and purification, Protein expression & purification
ISSN 1096-0279
OCLC 36951598
Material type Document, Periodical, Internet resource
Document type Internet Resource, Computer File, Journal / Magazine / Newspaper

Publisher details

Elsevier

  • Pre-print
    • Author can archive a pre-print version
  • Post-print
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  • Conditions
    • Authors pre-print on any website, including arXiv and RePEC
    • Author's post-print on author's personal website immediately
    • Author's post-print on open access repository after an embargo period of between 12 months and 48 months
    • Permitted deposit due to Funding Body, Institutional and Governmental policy or mandate, may be required to comply with embargo periods of 12 months to 48 months
    • Author's post-print may be used to update arXiv and RepEC
    • Publisher's version/PDF cannot be used
    • Must link to publisher version with DOI
    • Author's post-print must be released with a Creative Commons Attribution Non-Commercial No Derivatives License
    • Publisher last reviewed on 03/06/2015
  • Classification
    ​ green

Publications in this journal

  • [Show abstract] [Hide abstract]
    ABSTRACT: The progressive increase in Leishmania resistance to current control approaches prompts the need to develop therapeutic strategies based on comprehensive knowledge of the parasite's biology. The enzyme Nicotinamide Mononucleotide Adenylyltransferase (NMNAT, EC 2.7.7.1) catalyzes the central step in nicotinamide adenine dinucleotide (NAD(+)) biosynthesis, making it essential for the survival of all organisms. NAD(+) metabolism is related to the maintenance of several biochemical, cellular, and physiological processes; consequently, the characterization and analysis of the enzymes involved in its biosynthesis represent key steps in the development of control strategies. In this study, the NMNAT enzymes of different Leishmania species were identified using bioinformatics procedures. The sequences were used to construct structural homology models that revealed characteristic elements common to NMNATs. The open reading frame of L. braziliensis NMNAT was cloned from complementary DNA and the enzymatic activity of the corresponding recombinant protein was confirmed through enzymatic assays. Primary structure analysis revealed a Leishmania-specific amino-terminal insertion in NMNAT. The deletion of this insertion is negatively correlated with in vitro enzymatic activity. From our observations, we suggest the amino-terminal insertion of Leishmania NMNATs as a promising pharmacological target for the development of specific control strategies. Copyright © 2015. Published by Elsevier Inc.
    Protein Expression and Purification 08/2015; DOI:10.1016/j.pep.2015.08.022
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    ABSTRACT: Human-cl rhFVIII (Nuwiq(®)), a new generation recombinant factor VIII (rFVIII), is the first rFVIII produced in a human cell-line approved by the European Medicines Agency AIMS: To describe the development, upscaling and process validation for industrial-scale human-cl rhFVIII purification METHODS AND RESULTS: The purification process involves one centrifugation, two filtration, five chromatography columns and two dedicated pathogen clearance steps (solvent/detergent treatment and 20nm nanofiltration). The key purification step uses an affinity resin (VIIISelect) with high specificity for FVIII, removing essentially all host-cell proteins with >80% product recovery. The production-scale multi-step purification process efficiently removes process- and product-related impurities and results in a high-purity rhFVIII product, with an overall yield of ∼50%. Specific activity of the final product was >9000IU/mg, and the ratio between active FVIII and total FVIII protein present was >0.9. The entire production process is free of animal-derived products. Leaching of potential harmful compounds from chromatography resins and all pathogens tested were below the limit of quantification in the final product. Human-cl rhFVIII can be produced at 500L bioreactor scale, maintaining high purity and recoveries. The innovative purification process ensures a high-purity and high-quality human-cl rhFVIII product with a high pathogen safety margin. Copyright © 2015. Published by Elsevier Inc.
    Protein Expression and Purification 08/2015; DOI:10.1016/j.pep.2015.08.023
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    ABSTRACT: This paper deals with the purification of a class III endochitinase from Euphorbia characias latex. Described purification method includes an effective novel separation step using magnetic chitin particles. Application of magnetic affinity adsorbent noticeably simplifies and shortens the purification procedure. This step and the subsequently DEAE-cellulose chromatography enable to obtain the chitinase in homogeneous form. One protein band is present on PAGE in non-denaturing conditions and SDS-PAGE profile reveals a unique protein band of 36.5 ± 2 kDa. The optimal chitinase activity is observed at 50 °C, pH 5.0. E. characias latex chitinase is able to hydrolyze colloidal chitin giving, as reaction products, N-acetyl D-glucosamine, chitobiose and chitotriose. Moreover, we observed that calcium and magnesium ions enhance chitinase activity. Finally, we cloned the cDNA encoding the E. characias latex chitinase. The partial cDNA nucleotide sequence contains 762 bp, and the deduced amino acid sequence (254 amino acids) is homologous to the sequence of several plant class III endochitinases. Copyright © 2015. Published by Elsevier Inc.
    Protein Expression and Purification 08/2015; DOI:10.1016/j.pep.2015.08.026
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    ABSTRACT: Viral like particles (VLPs) have been used as immunogen for improvement of preventive vaccines against several viral infections in preclinical and clinical trials. These constructs can stimulate both cellular and humoral immunity. Two prophylactic HPV L1 VLP vaccines known as Gardasil and Cervarix were commercialized worldwide. However, there are main problems for expression and purification of VLPs in eukaryotic expression systems such as baculovirus and yeast leading to high cost of these vaccines. A novel Leishmania protozoan system has been applied to produce different recombinant proteins due to unique properties including generation of similar proteins with mammalian, easy handling, and large-scale culture. In the current study, we developed a novel strategy to produce HPV L1 VLP using stably transfected Leishmania cells. The positive transfectants were analyzed by SDS-PAGE and Western blot analysis. The assembly of purified L1 protein was detected by TEM microscopy. Finally, C57BL/6 mice were immunized by crude VLPs and antibody responses were assessed. The results of electronic microscopy revealed average 55-60 nm for L1 VLP. Furthermore, high IgG1 and IgG2a antibody responses were generated by L1 VLPs in mice similar to L1 VLPs produced in baculovirus-infected insect cells. Regarding the results, the amount of recombinant protein generated by leishmania was 2-3 mg/ 500 ml media, suggesting further optimization of this system for using in large animals and human. Copyright © 2015. Published by Elsevier Inc.
    Protein Expression and Purification 08/2015; DOI:10.1016/j.pep.2015.08.024
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    ABSTRACT: Design of experiment (DoE) is a statistics-based technique for experimental design that could overcome the shortcomings of traditional one-factor-at-a-time (OFAT) approach for protein purification optimization. In this study, a DoE approach was applied for optimizing purification of a recombinant single-chain variable fragment (scFv) against type 1 insulin-like growth factor receptor (IGF-1R) expressed in E. coli. In first capture step using Capto L, a 2-level fractional factorial analysis and successively a central composite circumscribed (CCC) design were used to identify the optimal elution conditions. Two main effects, pH and trehalose, were identified, and high recovery (above 95%) and low aggregates ratio (below 10%) were achieved at the pH range from 2.9 to 3.0 with 32%-35% (w/v) trehalose added. In the second step using cation exchange chromatography, an initial screening of media and elution pH and a following CCC design were performed, whereby the optimal selectivity of the scFv was obtained on Capto S at pH near 6.0, and the optimal conditions for fulfilling high DBC and purity were identified as pH range of 5.9-6.1 and loading conductivity range of 5-12.5 mS/cm. Upon a further gel filtration, the final purified scFv with a purity of 98% was obtained. Finally, the optimized conditions were verified by a 20-fold scale-up experiment. The purities and yields of intermediate and final products all fell within the regions predicted by DoE approach, suggesting the robustness of the optimized conditions. We proposed that the DoE approach described here is also applicable in production of other recombinant antibody constructs. Copyright © 2015. Published by Elsevier Inc.
    Protein Expression and Purification 08/2015; DOI:10.1016/j.pep.2015.08.020
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    ABSTRACT: Availability of highly purified proteins in quantity is crucial for detailed biochemical and structural investigations. Fusion tags are versatile tools to facilitate efficient protein purification and to improve soluble overexpression of proteins. Various purification and fusion tags have been widely used for overexpression in E. coli. However, these tags might interfere with biological functions and/or structural investigations of the protein of interest. Therefore, an additional purification step to remove fusion tags by proteolytic digestion might be required. Here, we describe a set of new vectors in which yeast SUMO (SMT3) was used as the highly specific recognition sequence of ubiquitin-like protease 1, together with other commonly used solubility enhancing proteins, such as glutathione S-transferase, maltose binding protein, thioredoxin and trigger factor for optimizing soluble expression of protein of interest. This tandem SUMO (T-SUMO) fusion system was tested for soluble expression of the C-terminal domain of TonB from different organisms and for the antiviral protein scytovirin. Copyright © 2015. Published by Elsevier Inc.
    Protein Expression and Purification 08/2015; DOI:10.1016/j.pep.2015.08.019
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    ABSTRACT: Many proteins contain intrinsically disordered regions that are highly solvent-exposed and susceptible to post-translational modifications. Studying these protein segments is critical to understanding their physiologic regulation, but proteolytic degradation can make them difficult to express and purify. We have designed a new protein expression vector that fuses the target protein to the N-terminus of the integral membrane protein, PagP. The two proteins are connected by a short linker containing the sequence SRHW, previously shown to be optimal for nickel ion-catalyzed cleavage. The methodology is demonstrated for an intrinsically disordered segment of cardiac troponin I. cTnI[135-209]-SRHW-PagP-His6 fusion protein was overexpressed in E. coli, accumulating in insoluble inclusion bodies. The protein was solubilized, purified using nickel affinity chromatography, and then cleaved with 0.5 mM NiSO4 at pH 9.0 and 50°C, all in 6 M guanidine-HCl. Nickel ion-catalyzed peptide bond hydrolysis is an effective chemical cleavage technique under denaturing conditions that preclude the use of proteases. Moreover, nickel-catalyzed cleavage is more specific than the most commonly used agent, cyanogen bromide, which cleaves C-terminal to methionine residues. We were able to produce 15 mg of purified cTnI[135-209] from 1 L of M9 minimal media using this protocol. The methodology is more generally applicable to the production of intrinsically disordered protein segments. Copyright © 2015. Published by Elsevier Inc.
    Protein Expression and Purification 08/2015; DOI:10.1016/j.pep.2015.08.018
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    ABSTRACT: Influenza virus is a Class I enveloped virus which is initially endocytosed into a host respiratory epithelial cell. Subsequent reduction of the pH to the 5-6 range triggers a structural change of the viral hemagglutinin II (HA2) protein, fusion of the viral and endosomal membranes, and release of the viral nucleocapsid into the cytoplasm. HA2 contains fusion peptide (FP), soluble ectodomain (SE), transmembrane (TM), and intraviral domains with respective lengths of ∼25, ∼160, ∼25, and ∼10 residues. The present work provides a straightforward protocol for producing and purifying mg quantities of full-length HA2 from expression in bacteria. Biophysical and structural comparisons are made between full-length HA2 and shorter constructs including SHA2 ≡ SE, FHA2 ≡ FP + SE, and SHA2-TM ≡ SE + TM constructs. The constructs are helical in detergent at pH 7.4 and the dominant trimer species. The proteins are highly thermostable in decylmaltoside detergent with Tm > 90 °C for HA2 with stabilization provided by the SE, FP, and TM domains. The proteins are likely in a trimer-of-hairpins structure, the final protein state during fusion. All constructs induce fusion of negatively-charged vesicles at pH 5.0 with much less fusion at pH 7.4. Attractive protein/vesicle electrostatics play a role in fusion, as the proteins are positively-charged at pH 5.0 and negatively-charged at pH 7.4 and the pH-dependence of fusion is reversed for positively-charged vesicles. Comparison of fusion between constructs supports significant contributions to fusion from the SE and the FP with little effect from the TM. Copyright © 2015. Published by Elsevier Inc.
    Protein Expression and Purification 08/2015; DOI:10.1016/j.pep.2015.08.021
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    ABSTRACT: Transient expression of heterologous proteins in mammalian systems is a powerful way to generate protein reagents quickly. However, it has historically suffered from poor yields in comparison to methods where the recombinant gene is stably integrated into the genome and high expressing clones isolated. Transient methods have been well described for HEK-based systems. In this paper we show the use of a design of experiments (DoE) approach to quickly analyse the effect of a range of different parameters on protein expression from a CHO-based transient system. We show that this system is amenable to a very simple transfection procedure by independent direct addition of DNA and transfection reagent to the culture vessel. In addition we show that expression can be improved by reducing the temperature of the culture conditions post-transfection. The process is demonstrated to be transferrable from 3ml cultures in deep 24-well plates through cultures in CultiFlask bioreactors, shake flasks and up to 25L culture in Wave Bioreactors. Data are shown to illustrate the utility of the system with a number of different classes of protein. Copyright © 2015. Published by Elsevier Inc.
    Protein Expression and Purification 08/2015; DOI:10.1016/j.pep.2015.08.016
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    ABSTRACT: Feruloyl esterases (FAEs) are key enzymes involved in the complete biodegradation of lignocelluloses, which could hydrolyze the ester bonds between hemicellulose and lignin. The coding sequence of a feruloyl esterase A (AtFaeA) was cloned from Aspergillus terreus and the recombinant AtFaeA was constitutively expressed in Pichia pastoris. The SDS-PAGE analysis of purified AtFaeA showed two protein bands owing to the different extent of glycosylation, and the recombinant AtFaeA had an optimum temperature of 50 °C and an optimum pH of 5.0. The substrate utilization and primary sequence identity of AtFaeA demonstrated that it is a type-A feruloyl esterase. The hydrolysis of corn stalk and corncob by xylanase from A. niger could be significantly improved in concert with recombinant AfFaeA. Copyright © 2015. Published by Elsevier Inc.
    Protein Expression and Purification 08/2015; DOI:10.1016/j.pep.2015.08.015
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    ABSTRACT: Aquaporins are integral membrane channel proteins found in all kingdoms of life. The Escherichia coli aquaporin Z (AqpZ) has been shown to solely conduct water at high permeability. Functional AqpZ is generally purified from the membrane fraction. However, the quantity of the purified protein is limited. In this study, a new method is developed to achieve high yield of bioactive AqpZ protein. A mild detergent n-dodecyl-β-D-maltopyranoside (DDM) was used to solubilize the over-expressed insoluble AqpZ from inclusion bodies without a refolding process. The recovered AqpZ protein showed high water permeability comparable with AqpZ obtained from the membrane fraction. In this way, the total yield of bioactive AqpZ has been increased greatly, which will facilitate the structural and functional characterization and future applications of AqpZ. Copyright © 2015. Published by Elsevier Inc.
    Protein Expression and Purification 08/2015; DOI:10.1016/j.pep.2015.08.014
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    ABSTRACT: Mixed-mode chromatography uses a multimodal functional resin, mainly composed of electrostatic and aromatic/hydrophobic groups. Here we have tested 2 mixed-mode resins, anion-exchange Capto adhere and cation-exchange Capto MMC, using 2 model proteins, i.e., an Fc-fusion etanercept, and bovine serum albumin (BSA). When etanercept was produced in Chinese hamster ovary cells, a large amount of misfolded species was generated. A novel technology to achieve effective separation of the misfolded or aggregated species has been developed in this study using these mixed-mode columns and elution conditions that combine pH change and NaCl or arginine at different concentrations. Etanercept, which has been purified by Protein-A chromatography, was bound to the Capto MMC or Capto adhere columns under various conditions and eluted by modulating the pH and salt or arginine concentration. The misfolded species occurred in the fractions at higher salt or arginine concentrations, most likely reflecting stronger electrostatic and hydrophobic interactions of the misfolded species with these mixed-mode resins. Another model protein, BSA, containing several oligomeric species, was also subjected to Capto adhere or Capto MMC chromatography using either NaCl or arginine gradient elution, with a greater recovery by arginine gradient. The oligomers were effectively separated on these mixed-mode columns using either gradient elution, eluting in later fractions similar to etanercept misfolded species. Copyright © 2015. Published by Elsevier Inc.
    Protein Expression and Purification 08/2015; DOI:10.1016/j.pep.2015.08.013
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    ABSTRACT: Destabilase-lysozyme (mlDL) is an enzyme secreted by the salivary gland cells of medicinal leeches. Destabilase-lysozyme possesses lysozyme and isopeptidase activities. We generated recombinant destabilase-lysozyme isoform 2 in three expression systems, i.e., in the bacteria Escherichia coli, in the yeast Pichia pastoris, and in the human cell line Expi293F. In E. coli, we generated both polypeptide in inclusion bodies that was later undergone to the refolding and soluble protein that had been fused with the chaperone SlyD. The chaperone was later cleaved by a specific TEV-protease. In cultures of the yeast P. pastoris and the human cell line Expi293F, the soluble form of destabilase-lysozyme was accumulated in the culture media. For the generated enzymes, we determined the lysozyme, isopeptidase and fibrinolytic activities and tested their general antimicrobial effects. The comparisons of the enzymes generated in the different expression systems revealed that all of the destabilase-lysozymes obtained in the soluble forms possessed equal levels of lysozyme, isopeptidase and fibrinolytic activities that exceeded several to ten times the levels of the same activities of the destabilase-lysozyme renaturated from the inclusion bodies. A similar pattern of the differences in the levels of the general antimicrobial effects was observed for the destabilase-lysozymes generated in the soluble form and as inclusion bodies. Copyright © 2015. Published by Elsevier Inc.
    Protein Expression and Purification 08/2015; DOI:10.1016/j.pep.2015.08.012
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    ABSTRACT: The novel bacterium, Rhodococcus sp. PKPD-CL was isolated and identified from the 'Chilika Lake' located at Odisha state of India, which is a largest brackish water habitat in Asia. Rhodococcus sp. PKPD-CL produces extracellular halo tolerant, detergent and organic solvent stable alkaline cholesterol oxidase. It has apparent molecular weight of 60 kDa and was purified 59 fold by using 60% saturated ammonium sulfate fractionation, anion exchange followed by size exclusion chromatographic techniques with 37% recovery. It showed substrate specificity for 3β-hydroxysteroids with Km of 1.1 × 10(-4) M for cholesterol. The pH, 8.0 and the temperature, 37°C were required for its optimum activity. Enzyme is considerably stable at pH, 6.0-8.5 and temperature up to 50°C. At 4°C and 30°C it maintained its 100% activity up to 60 days. The isoelectric point of the enzyme was 9.5. It showed 80% residual activity with 20% NaCl (3.42 M) and 83% relative activity with 12% NaCl (2.05 M) concentration. The metal ions like Zn(2+), Cu(2+), Ag+, Fe(3+), Ba(2+) inhibited the enzyme activity > 60% while Hg(2+) served a potent inhibitor whereas Mg(2+) found to be a good enhancer for it. The enzyme was stable in presence of chemical reagents (NaN3, EDTA), detergents (Tween-80, Tween-20, Triton X-100, sodium cholate) and various organic solvents (isopropanol, ethanol, benzene, chloroform, methanol, toluene, ethyl acetate, butanol and dimethylsulfoxide). Such a multi stress tolerant and versatile enzyme produced by Rhodococcus sp. PKPD-CL may serve as a good choice for industrial applications. Copyright © 2015. Published by Elsevier Inc.
    Protein Expression and Purification 08/2015; DOI:10.1016/j.pep.2015.08.011
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    ABSTRACT: Bone morphogenetic proteins (BMPs) have been applied in bone regeneration therapy due to their significant osteogenic activity, however, the complicated processing and high cost in producing recombinant BMP have limited their use in the clinic. In this study, we have developed a simple method to prepare recombinant human BMP7-BMP2 fusion protein with a flexible peptide linker (rhBMP7-2). The rhBMP7-2 protein is expressed efficiently in E. coli, and the denatured protein purified by anion exchange chromatography then refolded by dialysis. The yield was about 6.8 mg per gram of wet cell weight. The bioactivity of re-folded rhBMP7-2 was measured by alkaline phosphatase assay and alizarin red staining using both C2C12 and MC3T3-E1 cells, and also using the rat subcutaneous ectopic bone formation model. High level osteogenic activity was found in all the assays tested demonstrating the production of corrected folded and active rhBMP7-2 protein. Copyright © 2015. Published by Elsevier Inc.
    Protein Expression and Purification 08/2015; DOI:10.1016/j.pep.2015.08.010
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    ABSTRACT: Fibroblast growth factor 9 (FGF9) has autocrine and paracrine functions in chondrogenesis osteogenesis, hair growth, and gonadal differentiation. We have expressed recombinant human FGF9 (rhFGF9) in the oil bodies of Arabidopsis thaliana via the floral dip method. The expression vector pOTB-rhFGF9 contained an oleosin-rhFGF9 fusion gene and a glufosinate resistance gene for selection. This plasmid was transformed into Arabidopsis thaliana and expression of the fusion protein oleosin-rhFGF9 confirmed by SDS-PAGE and western blotting. Furthermore, MTT assays demonstrated that the oil bodies expressed oleosin-rhFGF9 from the transgenic Arabidopsis thaliana had a remarkable proliferation effect on NIH/3T3 cells. Copyright © 2015. Published by Elsevier Inc.
    Protein Expression and Purification 08/2015; DOI:10.1016/j.pep.2015.08.006
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    ABSTRACT: A novel gene encoding a thermostable esterase (designated as Est-gela) was isolated from the moderate thermophile Bacillus gelatini KACC 12197. The open reading frame of this gene (1170 bp) encodes 389 amino acid residues, and the molecular weight of Est-gela is approximately 42 kDa. The protein sequence of Est-gela shows similarity with β-lactamases and esterases (⩽43%). Est-gela contains the Ser-X-X-Lys conserved sequence (Ser58-Met59-Thr60-Lys61) and belongs to family VIII of esterases. We overexpressed Est-gela in Escherichia coli XL1-blue and purified this protein using a His tag. Est-gela showed a strong enzymatic activity toward p-nitrophenyl esters with short acyl chains (⩽C4) and the strongest activity toward p-nitrophenyl butyrate. Est-gela showed an enhanced enzymatic activity at 65 to 75 °C and retained more than 90% of the activity after incubation at 65 °C for 180 min. These results indicated that Est-gela was thermostable. In addition, Est-gela showed the maximal activity at pH 10. We also evaluated the effects of surfactants and organic solvents. Surfactants were more effective at improving the enzymatic activity than were organic solvents. Finally, Est-gela hydrolyzed (R,S)-ketoprofen ethyl ester (Kcat/Km = 5.0 ± 0.2 sec(-1)mM(-1), mean ± standard error) with enantioselectivity toward (S)-ketoprofen ethyl ester rather than (R)-ketoprofen ethyl ester. Copyright © 2015. Published by Elsevier Inc.
    Protein Expression and Purification 08/2015; DOI:10.1016/j.pep.2015.08.009
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    ABSTRACT: The market of therapeutic glycoproteins (including coagulation factors, antibodies, cytokines and hormones) is one of the profitable, fast-growing and challenging sectors of the biopharmaceutical industry. Although mammalian cell culture is still expensive and technically complex, the ability to produce desired posttranslational modifications, in particular glycosylation, is a major issue. Glycans can influence ligand binding, serum half-life as well as biological activity or product immunogenicity. Aiming to establish a novel production platform for recombinant glycoproteins, the human TE671 cell line was investigated. Since the initial analysis of cell membrane proteins showed a promising glycosylation of TE671 cells for biotechnological purposes, we focused on the recombinant expression of two model glycoproteins of therapeutical relevance. The optimization of the cell transfection procedure and serum-free expression succeeded for the human serine protease inhibitor alpha-1-antitrypsin (A1AT) and the hematopoietic cytokine granulocyte-macrophage colony-stimulating factor (GM-CSF). N-glycan analyses of both purified proteins by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry provided first fundamental insights into the TE671 glycosylation potential. Besides protein specific pattern, strong distinctions - in particular for N-glycan fucosylation and sialylation - were observed depending on the medium conditions of the respective TE671 cell cultivations. The cell line's ability to synthesize complex and highly sialylated N-glycan structures has been shown. Our results demonstrate the TE671 cell line as a serious alternative to other existing human expression systems. Copyright © 2015. Published by Elsevier Inc.
    Protein Expression and Purification 08/2015; DOI:10.1016/j.pep.2015.08.008
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    ABSTRACT: Secretory phospholipase A2 (sPLA2) catalyzes the hydrolysis of sn-2 linkage in the glycerophospholipid, thereby releasing fatty acid and 1-acyl lysophospholipid. Among sPLA2s from various organisms and tissues, group XIV fungal/bacterial sPLA2s are relatively less characterized compared to their mammalian counterparts. Here we report cloning, recombinant expression, refolding, and enzymatic characterization of two sPLA2s, NCU06650 and NCU09423, from the filamentous fungus Neurospora crassa. The hexahistidine-tagged putative mature region of both proteins were expressed in Escherichia coli. Inclusion bodies were solubilized using a high hydrostatic pressure refolding technique. NCU06650 was solublized without any additives at alkaline pH, and the addition of arginine or non-detergent sulfobetain (NDSB) significantly improved the process at acidic pH. In contrast, NCU09423 was solubilized only when NDSB was added at alkaline pH. Both enzymes displayed a Ca(2+)-dependent lipolytic activity toward E. coli membrane. Mass spectrometry analysis using the synthetic phospholipids as substrates demonstrated that both enzymes preferentially cleaved the sn-2 ester linkage of substrates and generated 1-acyl lysophospholipids, demonstrating that they are bona fide PLA2. Copyright © 2015. Published by Elsevier Inc.
    Protein Expression and Purification 08/2015; DOI:10.1016/j.pep.2015.08.007
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    ABSTRACT: Human meprin β (h-meprin β), a single-zinc metalloendoprotease of the astacin family, is potentially involved in disorders such as fibrosis and Alzheimer's Disease. Here, we describe the expression of the enzyme in the yeast Pichia pastoris. The N-terminal signal sequence was replaced by the α-leader of Saccharomyces, enabling efficient secretion of the mature enzyme, harboring either an N-terminal or C-terminal His-tag. The purification by affinity and hydrophobic interaction chromatography resulted in isolation of 58.4 mg/l of homogenous human pro-meprin β from fermentation broth. The activated enzyme isolated from yeast (yh-meprin β) displayed virtually identical enzymatic activity as h-meprin from a mammalian cell line. Furthermore, the yh-meprin β was N-glycoslyated and secreted as a dimer with a molecular mass of 148 kDa. Endoglycosidase H treatment generated a protein with a molecular mass of 133 kDa, but essentially unchanged kinetic parameters. Thus, our data suggest that human meprin β expressed in P. pastoris displays virtually identical parameters as meprin from other sources. The high yield of protein expression, the ease of purification and the deglycosylation in its native state appear to favor further studies aiming at inhibitor screening and structure-based inhibitor refinement. Copyright © 2015. Published by Elsevier Inc.
    Protein Expression and Purification 08/2015; DOI:10.1016/j.pep.2015.08.001