• Korean Journal of Agricultural Science
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• v.13 no.2
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• pp.299-310
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• 1986

The ovine squamous cell carcinoma (OSCC)-specific and immunosuppressive properties of OSCC extracts were investigated by using the techniques of lymphocyte blastogenicity, acid dissociation-ultrafiltration and gradient polyacrylamide gel electrophoresis. It was found that OSCC extracts contained two major and one minor protein peaks by Sephadex gel fractionation. Two major peaks bear substantial amount of immunoglobulins, antigen-antibody complex and OSCC-specific fractions, and the minor peak includes immunosuppressive materials. OSCC-specific components were detected at the molecular weights of 10,000 to 100,000 daltons in the major peaks and immunosuppressive materials at the fractions with the molecular weight of 10,000 to 100,000 and < 10,000 daltons in the minor peak. When the fractions were further separated by gradient polyacrylamide gel electrophoresis, the OSCC-specific antigens were found in the slice number 4 to 6 in fraction III, and immunosuppressive materials, in the slice numbers 9 to II in fraction V. The present results were considered to provide a basis for preparation and purification of OSCC-specific and immunosuppressive materials from the crude OSCC extracts.

• Fisheries and Aquatic Sciences
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• v.8 no.4
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• pp.213-219
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• 2005

Vitellogenin (VTG) was purified from the blood plasma of estradiol-17$\beta$ ($E_2$)-treated male marbled sole (Limanda yokohamae) using gel filtration and anion exchange chromatography. The purity of the marbled sole VTG (msVTG) was confirmed by polyacrylamide gel electrophoresis (SDS-PAGE) and N-terminal amino acid sequencing. The purified msVTG was used to produce monoclonal and polyclonal antibodies in mice and rabbits, respectively, and the specificity of the polyclonal antisera for msVTG was confirmed by Western blot analysis. The antibodies cross­reacted with a protein of molecular mass approximately 160 kDa in the plasma samples of mature female marbled sole. No cross-reactivity was observed with the plasma of male fish. A direct non-competitive sandwich enzyme-linked immunosorbent assay (ELISA) was developed using the monoclonal anti-msVTG and polyclonal anti-msVTG antibodies, with purified msVTG as the standard protein. The values of the intra- and inter-assay variations were within the ranges of $8.l-9.8\%$ and $8.5-12.2\%$, respectively. The sensitivity was about 0.3 ng/mL. Serial dilutions of plasma from mature female sole reacted with the msVTG-antibodies in the sandwich ELISA, whereas the plasma from male fish did not. The results indicate that the maturation status of female marbled sole can be identified using a sandwich ELISA for msVTG.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.3
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• pp.571-575
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• 2004

Escherichia coli O157:H7 cause hemorrhagic colitis and the extraintestinal complication of hemolytic-uremic syndrome, with their higher incidence occurring in children. Lipopolysaccharide (LPS) of E. coli O157:H7 is very important to make IgG anti-LPS with bactericidal activity. To identify the characteristic of E. coli OI57:H7, we isolated 60 MDa plasmid and amplified stx genes of shiga-like toxin (Stx) 1, 2 of E. coli O157:H7 by polymerase chain reaction (PCR) method. Using the simple purification method which contained phenol extract, ethanol precipitation and gel filtration steps, the LPS of E. coli O157:H7 was isolated and purified. Finally, we confirmed the purity of LPS through SDS-PAGE and silver nitrate staining.

• Biomedical Science Letters
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• v.2 no.2
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• pp.231-240
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• 1996

Human blood clotting (coagulation) factor 9 cDNA which codes for 461 amino acid has been cloned by screening human fetal liver cDNA library using PCR. This 1.4 kb cDNA spanning from the ATG initiation codon to the TAA termination codon was cloned into bacterial .expression vector pGEX-2T, generating pGEX-F9 plasmid. The plasmid pGEX-F9 expresses about 73 kDa GST (Glutathione S-transferase)-Factor 9 fusion protein when introduced into E. coli. Western blot analysis using polyclonal antibody raised against human factor 9 confirmed this fusion protein contains factor 9 protein. The level of GST-factor 9 expression was about 20% of total protein and the purification of fusion protein was efficiently achieved by using GST agarose bead based on one step purification protocol.

• Korean Chemical Engineering Research
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• v.49 no.6
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• pp.798-803
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• 2011

IgY(Immunoglobulin Yolk) is a specific antibody in egg yolk, and it protects human body from virus and antigen. There are a lot of egg yolk components such as lipoprotein and protein. To separate IgY, HPLC(High Performance Liquid Chromatography) and precipitation were used in a batch mode and SMB(Simulated Moving Bed) was adopted for continuous purification of yolk proteins. IgY and other proteins in yolk were separated by using three-zone SMB chromatography. Before performing SMB experiments, batch chromatography and PIM(pulse input method) were performed to find operation parameters and adsorption isotherms. The results of batch chromatography were compared with simulated results using Aspen chromatography. To find the most suitable separation condition in SMB chromatography, simulations in $m_2$-$m_3$ plane on the triangle theory were carried out. $m_2$ = 0.18, $m_3$ = 1.0 and ${\Delta}$t = 419 s are the best conditions for the highest purity of IgY. With this operating parameters(flow rate in three zone and switching time), the purity of raffinate results in 98.39% from Aspen chromatography simulation. Most of the simulation reached steadystate within second recycle.

• BMB Reports
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• v.29 no.6
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• pp.555-563
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• 1996

A membrane-bound phosphatidylinositol 4-kinase (PI 4-kinase) was separated in a sucrose gradient and solubilized with 1% Triton X-100 from mouse brain. The enzyme was purified 2,952-fold by various chromatographic techniques including DEAE-cellulose, PI-Sepharose and Sephacryl S-200 gel filtration. The molecular weight of PI 4-kinase was approximately 76 kDa by gel filtration and 70.8 kDa by SDS-polyacrylamide gel electrophoresis. The purified enzyme exhibited specific activity of 11.2 nmol/min/mg protein and pi value of 4.7. Kinetic analysis of the PI 4-kinase indicated apparent $K_m$, values of 190 ${\mu}M$ and 120 ${\mu}M$ for phosphatidylinositol and ATP, respectively. The maximal activity of this purified enzyme was observed at pH 7.4 at an incubation temperature of $37^{\circ}C$. The enzyme activity was significantly activated by $Mg^{2+}$, $Mn^{2+}$ and $Fe^{2+}$, and inhibited severely by $Ca^{2+}$. PI 4-kinase was proved to be pure in its immunoblot test by polyclonal antibody prepared from immunized rabbit sera. By this test, we were able to detect the existence of the same type of PI 4-kinase from other mouse organ tissues, such as liver, heart, kidney and spleen. Furthermore, similar immunoblot analysis with the same antisera recognized the different epitopes of PI 4-kinase proteins from various organs of rabbit, chinese hamster and rat.

• Journal of Microbiology
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• v.43 no.1
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• pp.21-27
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• 2005

A soluble Cr(VI) reductase was purified from the cytoplasm of Escherichia coli ATCC 33456. The molecular mass was estimated to be 84 and 42 kDa by gel filtration and SDS-polyacrylamide gel electrophoresis, respectively, indicating a dimeric structure. The pI was 4.66, and optimal enzyme activity was obtained at pH 6.5 and $37^{\circ}C$. The most stable condition existed at pH 7.0. The purified enzyme used both NADPH and NADH as electron donors for Cr(VI) reduction, while NADPH was the better, conferring 61% higher activity than NADH. The $K_m$ values for NADPH and NADH were determined to be 47.5 and 17.2 umol, and the $V_max$ values 322.2 and 130.7 umol Cr(VI) $min^{-1}mg^{-1}$ protein, respectively. The activity was strongly inhibited by N-ethylmalemide, $Ag^{2+},\;Cd^{2+},\;Hg^{2+}$, and $Zn^{2+}$. The antibody against the enzyme showed no immunological cross reaction with those of other Cr(VI) reducing strains.

• Journal of Life Science
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• v.28 no.12
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• pp.1416-1423
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• 2018

With strong biotin binding affinity ($K_D=10^{-14}M$), the tetrameric feature of streptavidin could be used to increase the antigen binding activity of a camel heavy chain (VHH) antibody through their fusion, here stained with biotinylated horseradish peroxidase and subsequent immunoassays ELISA and Western blot analysis. For this application, we cloned the streptavidin gene amplified from the Streptomyces avidinii chromosome by PCR, and this was fused to the gene of the 8B9 VHH antibody which is specific to green fluorescent protein (GFP) antigens. To express a soluble fusion protein in Escherichia coli, we used the pUC119 plasmid-based expression system which uses the lacZ promoter for induction by IPTG, the pelB leader sequence at the N-terminus for secretion into the periplasmic space, and six polyhistidine tags at the C-terminus for purification of the expressed proteins using an $Ni^+$-NTA-agarose column. Although streptavidin is toxic to E. coli because of its strong biotin binding property, this soluble fusion protein was expressed successfully. In SDS-PAGE, the size of the purified fusion protein was 122.4 kDa in its native condition and 30.6 kDa once denatured by boiling, suggesting the tetramerization of the monomeric subunit by non-covalent association through the streptavidin moiety fusing to the 8B9 VHH antibody. In addition, this fusion protein showed biotin binding activity similar to streptavidin as well as GFP antigen binding activity through both ELISA and Western blot analysis. In conclusion, the protein resulting from the fusion of an 8B9 VHH antibody with streptavidin was successfully expressed and purified as a soluble tetramer in E. coli; it showed both biotin and GFP antigen binding activity suggesting the possible production of a tetrameric and bifunctional VHH antibody.

• BMB Reports
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• v.52 no.8
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• pp.496-501
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• 2019

Conventionally, immunotoxins have been produced as a single polypeptide from fused genes of an antibody fragment and a toxin. In this study, we adopted a unique approach of chemical conjugation of a toxin protein and an antibody fragment. The two genes were separately expressed in Escherichia coli and purified to high levels of purity. The two purified proteins were conjugated using a chemical linker. The advantage of this approach is its ability to overcome the problem of low recombinant immunotoxin production observed in some immunotoxins. Another advantage is that various combinations of immunotoxins can be prepared with fewer efforts, because the chemical conjugation of components is relatively simpler than the processes involved in cloning, expression, and purification of multiple immunotoxins. As a proof of concept, the scFv of trastuzumab and the PE24 fragment of Pseudomonas exotoxin A were separately produced using E. coli and then chemically crosslinked. The new immunotoxin was tested on four breast cancer cell lines variably expressing HER2. The chemically crosslinked immunotoxin exhibited cytotoxicity in proportion to the expression level of HER2. In conclusion, the present study revealed an alternative method of generating an immunotoxin that could effectively reduce the viability of HER2-expressing breast cancer cells. These results suggest the effectiveness of this method of immunotoxin crosslinking as a suitable alternative for producing immunotoxins.

• Journal of Life Science
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• v.17 no.10
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• pp.1321-1329
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• 2007

Deer antler tissue contains the most rapidly growing bone in the animal kingdom. Thus, it is likely that growing antler tissue is a rich source of local paracrine bone-stimulating factors. Growth factors, at least the insulin-like growth factor (IGF), control the bone-remodelling process. In this study, we tried to isolate and purify IGF-I from fresh antler tissue by the routine isolation and purification of protein. The purification involved ammonium sulfate precipitation, DEAE-Sepharose CL-60 ion-exchange chromatography, CM-Sepharose CL-6B ion-exchange chromatography, and Sephadex G-50 chromatography. Purified fractions from each step were analyzed by high-performance liquid chromatography (HPLC), SDS polyacrylamide gel electrophoresis (SDS-PACE), Dot-blot, and Western-blot methods. Furthermore, the quantification of partially purified IGF-I was calculated by enzyme-linked immunosorbent assays (ELISA) using antibody to human recombinant IGF-1. SDS-PAGE analysis of the final fraction yielded two molecular bands and the signal band was at 12 kDa on the Western-blot film. This purified IGF-I fraction showed a peak at retention time of eight min. The quantity of IGF-I in 20 g deer antler tissue as starting weight was calculated using a standard curve to be 2910 ng/ml, and total IGF-I amount is 0.291 g. The results show that IGF-I, which can be found in deer antler, can be partially purified and quantified by classic protein isolation methods.