• Journal of Microbiology and Biotechnology
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• 제26권10호
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• pp.1808-1816
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• 2016

As a scaffolding subunit of the PIK3C3/VPS34 complex, Beclin 1 recruits a variety of proteins to class III phosphatidylinositol-3-kinase (VPS34), resulting in the formation of a distinct PIK3C3/VPS34 complex with a specific function. Therefore, the investigation of a number of Beclin 1 domains required for the protein-protein interactions will provide important clues to understand the PIK3C3/VPS34 complex, of which Beclin1-VPS34 interaction is the core unit. In the present study, we have designed a bacterial overexpression system for the Beclin 1 domain corresponding to VPS34 binding (Vps34-BD) and set up the denaturing purification protocol due to the massive aggregation of Vps34-BD in Escherichia coli. The expression and purification conditions determined in this study successfully provided soluble and functional Vps34-BD.

• BMB Reports
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• 제28권6호
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• pp.504-508
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• 1995

The electrophoretic patterns of plasma membrane surface proteins of normal rat liver cells and rat hepatomas were compared in 10% non-denaturing and 7-15% gradient non-denaturing gel. Chemical carcinogens, 2-Me DAB (2-methyl-4-dimethylaminoazobenzene) and DENA (diethylnitrosamine), were used to induce hepatoma in rats. One protein which disappeared in hepatoma was identified in normal rat liver by non-denaturing gel electrophoresis. Rabbit antisera were raised against this specific protein, and the protein was purified by Sephacryl S-200 column and immunoaffinity chromatography using the purified antibody. The purified protein showed two bands of molecular weights approximately 50 $kD_{\alpha}$ and 52 $kD_{\alpha}$ by SDS-polyacrylamide gel electrophoresis, which reacted specifically with the antibody. However only one band was observed in non-denaturing gel and also in isoelectric focusing with a pI value of 6.6. This study showed the existence of an unique protein on the plasma membrane surface of normal rat liver cells which disappeared in rat hepatomas induced by chemical carcinogens.

• Applied Biological Chemistry
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• 제41권7호
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• pp.522-526
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• 1998

콩 유용성분 탐색의 일환으로 그리고 향후 콩 ferritin 항체 및 유전자 확보를 목표로 발아된 콩으로부터 ferritin을 분리 정제하여 그 몇가지 특성을 조사하였다. 72시간 발아된 콩으로부터 ammonium sulfate 침전(0.55 saturation), DEAE-cellulose, Sephacryl S-300, Bio-Scale Q2 column chromatographies를 통하여 ferritin을 분리하였다. 정제된 콩 ferritin은 SDS-PAGE 분석에서 21 kDa의 크기를 나타냈으며, Sephacry S-300을 통한 겔거르기 chromatography와 non-denaturing 폴리아크릴아마이드 전기영동 분석에서 $510{\sim}560\;kDa$의 크기로 측정 되었다. 또한, immunodiffusion test에서 anti-soybean ferritin antiserum과 상호 반응하였다. 원자흡광광도계와 표준 철 용액을 이용한 정제된 콩 ferritin 중의 철 함유량은 833 mol Fe/mol protein 이었으며, 이는 호박씨로부터 분리한 ferritin보다 31배 더 많은 양의 철 함유량 이었다. 정제된 콩 ferritin중의 철은 horse spleen ferritin 중의 철과 유사하게 iron staining 되었다.

• BMB Reports
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• 제28권4호
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• pp.281-289
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• 1995

Homogeneous human deoxycytidine kinase was purified in one step from a variety of spontaneous human leukemic cells (T-ALL, B-ALL, B-CLL, AML, CML), and from cultured T-lymphoblast cells (MOLT-4) using the newly developed affinity medium, $dCp_4$-Sepharose. Starting with an ammonium sulfate fraction, purification was achieved in one step with the kinase being eluted from a column by the end product inhibitor, dCTP. The purified deoxycytidine kinase from T-ALL cells phosphorylated deoxyadenosine and deoxyguanosine, as well as deoxycytidine. The enzyme purified from T-ALL and B-CLL cells yielded one major band with a molecular weight of 52 kDa determined by SDS-polyacrylamide gel electrophoresis. AML and CML cells yielded one 52 kDa band and an extra band of 30 kDa molecular weight. On the other hand, B-ALL and MOLT-4 cells showed a low molecular weight band of 30 kDa only. However, the electrophoretic mobilities of enzymatic activity in 12% non-denaturing gels were identical for the dCyd kinase from all different kinds of leukemic cell lines, except that the B-ALL, B-CLL, and MOLT-4 cell preparations had an extra minor peak, all at the same position. dAdo and dCyd phosphorylating activities comigrated indicating that these activities are all associated with the same protein. Two new methods, a disk implantation method and a nitrocellulose powder method were used with a small amount of enzyme protein to raise polyclonal antibodies against dCyd kinase purified from T-ALL cells.

• BMB Reports
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• 제44권4호
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• pp.279-284
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• 2011

The glutathione S-transferase (GST) system is useful for increasing protein solubility and purifying soluble GST fusion proteins. However, purifying half of the GST fusion proteins is still difficult, because they are virtually insoluble under non-denaturing conditions. To optimize a simple and rapid purification condition for GST-pyruvate kinase muscle 2 (GST-PKM2) protein, we used 1% sarkosyl for lysis and a 1 : 200 ratio of sarkosyl to Triton X-100 (S-T) for purification. We purified the GST-PKM2 protein with a high yield, approximately 5 mg/L culture, which was 33 times higher than that prepared using a conventional method. Notably, the GST-high-temperature requirement A2 (GST-HtrA2) protein, used as a model protein for functional activity, fully maintained its proteolytic activity, even when purified under our S-T condition. This method may be useful to apply to other biologically important proteins that become highly insoluble in the prokaryotic expression system.

• 대한수의학회지
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• 제45권2호
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• pp.185-189
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• 2005

Actinobacillus pleuropneumoniae is the causative agent of a porcine contagious pleuropneumonia. Among several virulence factors including exotoxin (Apx toxins), LPS, transferrin-binding proteins, OMPs, and some proteases, Apx toxins have been major targets for the protection study. In this study, cloning and expression of A. pleuropneumoniae Apx I and Apx II toxin, which are produced by all highly virulent strains, were performed by Escherichia coli expression system. Genes coding Apx I and II toxin were amplified from the A. pleuropneumoniae serotype 5 genomic DNA using polymerase chain reaction and cloned to a prokaryotic expression vector, pRSET. Expression of the Apx I and Apx II coding sequences in E. coli resulted in the formation of insoluble inclusion bodies purified according to a denaturing purification protocol, which employs the use of guanidium. Recombinant proteins were purified using $Ni^{2+}$-charged resin affinity purification. This expression and purification system made it possible to produce Apx I and Apx II in large amounts for further immunologic studies.

• Journal of Microbiology
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• 제37권4호
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• pp.234-242
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• 1999

To obtain the recombinant circumsporozoite (CS) protein for the diagnosis of patients and seroepidemiology of Plasmodium vivax malaria which have been prevalent in northern part of Kyonggido, the CS protein gene was amplified by the polymerase chain reaction (PCR) from genomic DNA of the Korean vivax malaria patient. The gene consists of 1,123 nucleotides except signal peptide sequences and had an uninterrupted reading frame encoding a protein of 374 amino acids with a central region of 20 tandem repeats of the nonapeptide. The CS protein gene was expressed in Escherichia coli and purified, the molecular weight of recombinant CS protein was about 44 kDa (monomer) under denaturing purification and about 65 kDa (dimer) under native purification by SDS-PAGE. The purified recombinant CS protein which has antigenicity to malaria patients in Western blot analysis and Enzyme-linked immunosorbent assay, reacted only with the serum of P. vivax (PV210) infected malaria patients with no cross reaction to the P. falciparum malaria patient. The recombinant CS protein purified in this study will serve as a useful antigen to support the diagnosis of malaria patients and seroepidemiology.

• 한국응용곤충학회지
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• 제37권1호
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• pp.59-64
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• 1998

꿀벌부채명나방 종령유충의 whole body에서 gel filtration 방법으로 유약호르몬 결합 단백질을 분리, 정제하였다. 분리된 단백질은 column chromatography법과 전기영동법에 의해 등가성을 확인하였다. 이 결합단백질은 전기 영동법에 의해 32K, gel filtration 에 의해 28K의 상대적 분자량을 나타냈다. 또한, JH III에 대한 해리도는 3.9$\times$${10}^{-7}$M로 확인되었다.

• 한국미생물·생명공학회지
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• 제29권4호
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• pp.248-252
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• 2001

메탄올 자화효모 Hansenula polymorpha 가 생산하는 재조합 인체 알부민 (human albumin)을 heat treatment ultrafiltration phenyl Sepharose CL-4B Mono Q 컬럼 크로마토그래피를 수행하여 수율 60%로 정제하였다. 정제된 재보합 알부민 SDS-PAGE를 수행한 결과 분자량이 65,000 Da으로 나타났고, 본 재조합 알부민의 N-말단 아미노산 서열은 Asp- Ala- His- Lys- Ser- Glu- Ala 으로 혈청유래 알부민 및 다른 효모 유래의 재조합 인체 알부민 과 동일함을 보였다. 정제한 재조합 인체 알부민의 아미노산 조성은 총 18종 의 아미노산이 검출되었고 아미노산 잔기 중 cysteine, arginine lysine 등이 이론치와 일치하였으며, 혈청 알부민과 동일하게 약 pI 4.8 정도 값을 나타내어 H. polymorpha 유래의 재조합 단백질의 전반적인 아미노산 구성이 혈청 알부민과 동일함을 확인하였다.

• Journal of Microbiology and Biotechnology
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• 제13권5호
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• pp.738-744
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• 2003

The gene ADH encoding NAD-dependent alcohol dehydrogenase from Bacillus stearothennophilus was cloned and overexpressed as a GST fusion protein at a high level in Escherichia coli. The expressed fusion protein was purified simply by glutathione affinity chromatography. GST fusion protein was then cleaved by thrombin, while soluble enzyme was further purified by glutathione affinity chromatography. The recombinant enzyme had the same elctrophoretic mobility as the native enzyme from Bacillus stearothennophilus. The recombinant enzyme catalyzed the oxidation of a number of alcohols and exhibited high activities towards secondary alcohols. The $K_m\;and\;V_{max}$ values of the recombinant enzyme for ethanol were 5.11 mM and 61.35 U/mg, respectively. Pyridine and imidazole notably inhibited the enzymatic activity. The activity of the recombinant enzyme optimally proceeded at pH 9.0 and $70^{\circ}C$. The midpoint of the temperature-stability curve for the recombinant enzyme was approximately $68^{\circ}C$, and the enzyme was not completely inactivated even at $85^{\circ}C$. The recombinant enzyme showed a high resistance towards denaturing agents (0.05% SDS, 0.1 M urea). Therefore, due to its stability and relatively broad substrate specificity, the recombinant enzyme could be utilized in bio-industrial processes and biosensors.