• Molecular & Cellular Toxicology
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• v.3 no.2
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• pp.85-89
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• 2007

Efficient gene delivery to specific tissues, such as inflammatory and cancerous tissues, is currently a major concern in disease treatment. The human transferrin receptor (hTR) has been detected in the synovium and fibroblast-like synoviocytes (FLS), which raises the possibility that expression of hTR is associated with the pathogenesis of rheumatoid arthritis (RA). To investigate whether the hTR is a useful target for gene transduction into the FLS of RA patients, recombinant adenoviruses with wildtype fiber (AdLac) and transferrin peptide-tagged fiber (Tf-AdLac) were used. The hTR expression level in FLS was notably increased by basic fibroblast growth factor (bFGF). Gene transduction to FLS was significantly higher by the hTR-targeted adenovirus than by the AdLac adenovirus, and treatment of the FLS with bFGF resulted in increased gene transduction by Tf-AdLac. Taken together, these data support Tf-AdLac as a new strategy for gene transduction in the treatment of RA patients.

• YAKHAK HOEJI
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• v.45 no.2
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• pp.227-236
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• 2001

The complexity and variability of both the biologicals and the bioassays used to test them led to the use of the reference standard- a sample of the product of defined purity and potency, against which all preparations of that product must be calibrated. In order to prepare and establish KFDA reference standard for recombinant human growth hormone (somatropin), somatropin substance was filled in ampoules in National Institute for Biological Standards and Control (NIBSC). The candidate KFDA reference standard for somatropin (designated as 98/674) was evaluated to determine the suitability of serving as a KFDA reference standard for somatropin by the collaborative study, in which 10 laboratories participated. Physicochemical analysis and in vivo bioassay were performed by direct comparison with the international somatropin standard 88/624. 98/674 was identified as somatropin by SDS-PAGE, IEF, peptide mapping, and HPLC. Determination of somatropin content by SE-HPLC yielded a mean estimate of 2.01 mg somatropin per ampoule. Data from the study also yielded mean values of 0.39 $\pm$ 0.26% for high molecular weight impurities by SE-HPLC and mean values of 2.13 $\pm$ 1.29% for somatropin related proteins by RP-HPLC. Estimates of relative potency by weight gain bioassay in the hypophysectomised rats showed that relative potency of KS 98/674 was 1.07 aganist IS 88/624. Based on the results of the collaborative study, the candidate reference standard for somatropin is suitable to serve as a KFDA reference standard for somatropin.

• Biotechnology and Bioprocess Engineering:BBE
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• v.6 no.2
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• pp.144-149
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• 2001

For the production and purification of a single chain human insulin precursor, four types of fusion peptides $\beta$-galactosidase (LacZ), maltose binding protein (MBP), glutathione-S-transferase (GST), and (His)(sub)6-tagged sequence (HTS) were investigated. Recombinant E. coli harboring hybrid genes was cultivated at 37$\^{C}$ for 1h, and gene induction occurred when 0.2mM of isopropyl-D-thiogalactoside (IPTG) was added to the culture broth, except for E. coli BL21 (DE3) pLysS harboring a pET-BA cultivation with 1.0mM IPTG, followed by a longer than 4h batch fermentation respectively. DEAE-Sphacel and Sephadex G-200 gel filtration chromatography, amylose affinity chromatography, glutathione-sepharose 4B affinity chromatography, and a nickel chelating affinity chromatography system as a kind of immobilized metal ion affinity chromatography (IMAC) were all employed for the purification of a single chain human insulin precursor. The recovery yields of the HTS-fused, GST-fused, MBP-fused, and LacZ-fused single chain human insulin precursors resulted in 47%, 20%, 20%, and 18% as the total protein amounts respectively. These results show that a higher recovery yield of the finally purified recombinant peptides was achieved when affinity column chromatography was employed and when the fused peptide had a smaller molecular weight. In addition the pET expression system gave the highest productivity of a fused insulin precursor due to a two-step regulation of the gene expression, and the HTS-fused system provided the highest recovery of a fused insulin precursor based on a simple and specific separation using the IMAC technique.

• KSBB Journal
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• v.18 no.4
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• pp.306-311
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• 2003

Solid-phase refolding of immobilized proteins can be an effective way to reuse an immobilized enzyme column. Oriented immobilization methods are known to provide higher activity of the immobilized enzymes. In this study, using recombinant EK (enterokinase) as a model enzyme and a fusion protein, that consisted of recombinant human growth hormone and six His tag that was linked by the peptide of EK-specific recognition sequence, as a model substrate, we evaluated two oriented immobilization methods, i. e., reductive alkylation of N-terminus ${\alpha}$-amine and affinity interaction between poly-histidine tag and Ni-NTA (nickel-nitrilotriacetic acid). The immobilization yield, activity and cleavage of the immobilized enzymes, and the yield of solid-phase refolding were compared. The Ni affinity immobilization and the covalent immobilization yields were about 100％ and 65％, respectively. But the specific activities were the same, about 50％ of that of the soluble enzyme. The cleavage rate by the covalently immobilized EK was higher than the soluble enzyme and the side reaction of cryptic cleavage was significantly decreased. Covalently immobilized EK showed almost 100％ refolding yield but the affinity immobilized EK showed only 70％ yield, which suggested the covalent conjugation provided more rigid ‘reference structure’ for the solid-phase refolding. The monomeric hGH could be easily obtained by capturing the cleaved poly Histidine tag by the Ni affinity column.

• Journal of Microbiology and Biotechnology
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• v.24 no.3
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• pp.337-345
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• 2014

Pichia pastoris is one of the most widely used expression systems for the secretory expression of recombinant proteins. The secretory expression in P. pastoris usually makes use of the prepro $MAT{\alpha}$ sequence from Saccharomyces cerevisiae, which has a dibasic amino acid cleavage site at the end of the signal sequence. This is efficiently processed by Kex2 protease, resulting in the secretion of high levels of proteins to the medium. However, the proteins that are having the internal accessible dibasic amino acids such as KR and RR in the coding region cannot be expressed using this signal sequence, as the protein will be fragmented. We have identified a new signal sequence of 18 amino acids from a P. pastoris protein that can secrete proteins to the medium efficiently. The PMT1-gene-inactivated P. pastoris strain secretes a ~30 kDa protein into the extracellular medium. We have identified this protein by determining its N-terminal amino acid sequence. The protein secreted has four DDDK concatameric internal repeats. This protein was not secreted in the wild-type P. pastoris under normal culture conditions. We show that the 18-amino-acid signal peptide at the N-terminal of this protein is useful for secretion of heterologous proteins in Pichia.

• Proceedings of the Korean Society of Toxicology Conference
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• 1997.10a
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• pp.38-42
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• 1997

Human growth hormone is known as one of the peptide hormones which is consisted of 191 amino acids derived from the pituitary gland in humans. The objectives of this study were to supply inexpensive recombinant methionyl human growth hormones (rHGH) synthesized by the DNA technology in a yeast cell line and followed by the establishement of protein purification techniques. The next steps of the research were to study its physic-chemical properties and biological properties, and to evaluate various preclinical aspcts including pharmacokinetics sutdy, general pharmacology study, general toxicity test, and specific toxicity tests. Clinical phase I, II, III studies were also done against growth hormone dficient children to reveal that growth promoting effects were similar compared with the natural HGH extracted from pituitary glands and commercially available rHGHs. The results could be summarized that (I) this yeast dervied rHGH have had excellent physico-chemical and biological properties in comparison with a natural HGH and other synthesized rHGHs, (2) we could not see any toxic side effects when very high doses were administered to the experimental animals, and (3) this growth hormone showed effectiveness in the growth stimulating to growth hormone deficient patients.

• Journal of Microbiology and Biotechnology
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• v.33 no.6
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• pp.736-744
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• 2023

The introduction of the toxT-139F allele triggers the expression of TCP (toxin co-regulated pilus) and CT (cholera toxin) under simple laboratory culture conditions in most Vibrio cholerae strains. Such V. cholerae strains, especially strains that have been used in OCVs (oral cholera vaccines), can induce antibody responses against TCP in animal models. However, CT produced in these V. cholerae strains is secreted into the culture medium. In this study, V. cholerae strains that can express intracellular CTB under the control of the toxT-139F allele have been constructed for potential application in OCVs. First, we constructed a recombinant plasmid directly linking the ctxAB promoter to ctxB without ctxA and confirmed CTB expression from the plasmid in V. cholerae containing the toxT-139F allele. We constructed another recombinant plasmid to express NtrCTB, from which 14 internal amino acids-from the 7^th to the 20^th amino acid-of the leader peptide of CTB have been omitted, and we found that NtrCTB remained in the cells. Based on those results, we constructed V. cholerae strains in which chromosomal ctxAB is replaced by ntrctxB or ntrctxB-dimer. Both NtrCTB and NtrCTB-dimer remained in the bacterial cells, and 60% of the NtrCTB-dimer in the bacterial cells was maintained in a soluble form. To develop improved OCVs, these strains could be tested to see whether they induce immune responses against CTB in animal models.

• IMMUNE NETWORK
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• v.2 no.2
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• pp.102-108
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• 2002

Background: This study was aimed to differentiate two forms of CTLA-4 (CD152) in activated peripheral blood lymphocyte and clarify the mechanism how cytoplasmic form of this molecule is targeted to cell surface. Methods: For this purpose we generated 2 different anti-human CD152 peptide antibodies and 5 different N'-terminal deletion mutant CTLA4Ig fusion proteins and carried out a series of Western blot and ELISA analyses. Antipeptide antibodies made in this study were anti-CTLA4pB and anti-CTLA4pN. The former recognized a region on extracellular single V-like domain and the latter recognized N'-terminal sequence of leader domain of human CD152. Results: In Western blot, the former antibody recognized recombinant human CTLA4Ig fusion protein as an antigen. And this recognition was completely blocked by preincubating antipeptide antibody with the peptide used for the antibody generation at the peptide concentration of 200 ug/ml. These antibodies were recognized human CD152 as a cytoplasmic sequestered- and a membrane bound- forms in phytohemagglutinin (PHA)-stimulated peripheral blood lymphocyte (PBL). These two forms of CD152 were further differentiated by using anti-CTLA4pN and anti-CTLA4pB antibodies such that former recognized cytosolic form only while latter recognized both cytoplasmic- and membraneforms of this molecule. Furthermore, in a transfection expression study of 5 different N'-terminal deletion mutant CTLA4Ig, mutated proteins were secreted out from transfected cell surface only when more than 6 amino acids from N'-terminal were deleted. Conclusion: Our results implies that cytosolic form of CTLA-4 has leader sequence while membrane form of this molecule does not. And also suggested is that at least N'-terminal 6 amino acid residues of human CTLA-4 are required for regulation of targeting this molecule from cytosolic- to membrane- area of activated human peripheral blood T lymphocyte.

• KSBB Journal
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• v.24 no.6
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• pp.591-597
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• 2009

B-type natriuretic peptide is a neurohormone secreted in the cardiac ventricles. BNP levels are elevated in patients with ventricular dysfunction. Therefore, the concentration of BNP is important factor to reflect diagnosis and prognosis for cardiovascular disease. In this respect, anti-BNP scFv is an urgent requirement for early diagnosis in the field of biosensor. Herein, the genetic codes of anti-BNP scFv were chemically synthesized and cloned into both pET22b (+) and pColdⅣ vector, respectively. The recombinant scFv was successfully expressed as a functional form in cytoplasm of E. coli and detected through Western blot and ELISA. The highest level of functional expression of anti-BNP scFv was achieved using pET22b (+) vector at $15^{\circ}C$ by addition of 0.1 mM IPTG. Additionally, being exposed to both BNP and ANP, anti-BNP scFv specifically captured only BNP. Therefore, anti-BNP scFv expressed in this study will be applied to measure the concentration of BNP as a diagnostic recognition molecule.

• Journal of Plant Biotechnology
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• v.41 no.3
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• pp.159-167
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• 2014

In eukaryotes, proteins that are secreted into ER are post-translationally modified by N-glycosylation, the patterns of which are significantly different between plant and animal cells. Biotechnology industry has already produced a number of therapeutic glycoproteins in plant cells. However, the aberrant glycosylation of therapeutic recombinant proteins in plant systems can cause immune problems in humans. Therefore, it is important to develop strategies for producing non-glycosylated forms to preserve biological activity and native conformation by a peptide: N-glycanase (PNGase). In this study, we try to isolate PNGase T gene from tomato, which can use as a platform plant for biotechnology industry. We isolated a cDNA (GenBank Accession number KM401550) from tomato leaves with 1,767 bp, which encoded a polypeptide of 588 amino acids with a predicted molecular mass of 65.8 kDa. We also investigated the expression patterns of PNGase T during fruit ripening of tomato. The transcripts of PNGase T, which were constitutively induced in tomato fruit from green stage, were significantly increased and reached a peak at orange stage. After which, those transcripts were continuously reduced. The expression pattern of PNGase T was coincided well with transcripts profiles of metacaspase gene, LeMCA, and senescence-related gene members of ACC synthase, LeACS2, LeACS4, and LeACS6, for ethylene biosynthesis during fruit ripening. These results suggest that PNGase T is involved in a de-glycosylation process associated with senescence and fruit ripening.