• 한국생물물리학회:학술대회논문집
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• 한국생물물리학회 1999년도 학술발표회 진행표 및 논문초록
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• pp.45-45
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• 1999

Cytochrome c (cyt c) binds to acidic membranes at low ionic strength. Replacement of Lys-72 or Lys-87 by Glu reduced the binding affinity of cyt c toward large unilamellar vesicles (LUV) in liquid crystalline phase. The differences were smaller for LUV in gel phase. A fraction of bound cyt c was non-electrostatically associated.(omitted)

• 한국식품영양과학회지
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• 제26권6호
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• pp.1086-1090
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• 1997

Morphological properties on lintnerized maize starches with different amylose content were investigated. With increasing the lintnerization periods and decreasing the amylose content, hydrolysis rate was increased. As amylose content of starch was increased, the degree of damage with acid treatment was decreased by SEM. With increasing hydrolysis, iodine affinity, apparent amylose content and ${\lambda}_{max}$ of lintnerized starches were decreased. Water binding capacities of lintnerized starches were higher than those of native starches.

• 대한약학회:학술대회논문집
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• 대한약학회 2001년도 Proceedings of International Convention of the Pharmaceutical Society of Korea
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• pp.268.2-268.2
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• 2001

• 대한약리학회지
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• 제20권2호
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• pp.23-34
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• 1984

실험적으로 명암주기 또는 암주기에 적응시킨 백서의 간뇌 homogenate에서 opiate receptor의 일중변동 유무를 검토하고, circadian rhythm에 영향을 미치는 것으로 알려진 수종 중추작용약물의 영향을 보고 저 7 group에서 4시간 간격으로 1일 6회 maximum $^3H-morphine$ binding을 측정하여 다음과 같은 성적을 얻었다. 1) L : D, 12 : 12에 적응시킨 대조군에서 maximum $^3H-morphine$ binding은 22시에 최고에 달하는 매우 유의한 일중변동을 보였고, 24시간 평균 $^3H-morphine$ binding치는 $0.45{\pm}0.03\;pmole/mg Protein이었다. 2) 지속적인 암적응을 시킨 D : D, 12 :12군에서 $^3H-morphine$ binding의 일중변동은 14시에 최하, 그리고 2시에 최고의 binding치를 보이는 만상성의 일주변동은 보였으며 대조군의 곡선과는 그 shape, Phase, 진폭, 최고 또는 최하 binding시기 및 24시간평균 opiate수용체의 수에 현저한 차이가 있었다. 3) 지속적인 암적응, reserpine, pargyline, imipramine, amphetamine 또는 chlorpromazine 처리는 opiate receptor의 일중변동을 변화시켰다. 4) 그러나 전 실험군에서 Kd치는 변동되지 않았다. 이상 실험성적으로 백서뇌내 opiate수용체의 일중변동은 수용체의 질적변동이 아닌 수적인변동에 의하고, 지속적인 암적응이나 circadian rhythm을 변동시키는 중추성 약물들이 opiate receptor의 일중변동을 변화시킬 수 있으며, 또한 동통을 포함하여 제종 진통제의 효과가 일중변동을 일으키는 것은 opiate receptor의 일중변동과 일정한 관계가 있을 것으로 추측하였다.

• 대한의생명과학회지
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• 제11권4호
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• pp.487-492
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• 2005

The baculovirus/insect cell expression system is of great value in the study of structure-function relationships in mammalian glucose-transport proteins by site-directed mutagenesis and for the large-scale production of these proteins for mechanistic and biochemical studies. Spodoptera frugiperda Clone 21 (Sf2l) cells grow well on TC-100 medium that contains $0.1\%$ D-glucose as the major carbon source, strongly suggesting the presence of endogenous glucose transporters. However, very little is known about the properties of the endogenous sugar transporter(s) in Sf2l cells, although a saturable transport system for hexose uptake has been previously revealed in the Sf cells. In order to further examine the substrate and inhibitor recognition properties of the Sf2l cell transporter, the ability of hexoses to inhibit 2-deoxy-D-glucose (2dGlc) transport was investigated by measuring inhibition constants $(K_i)$. The $K_i's$ for reversible inhibitors were determined from plots of uptake versus inhibitor concentration. Transport was effectively inhibited by D-mannose and D-glucose. Of the hexoses tested, L-glucose had the least effect on 2dGlc transport in the Sf2l cells, indicating that the transport is stereoselective. Unlike the human HepG2 type glucose transport system, D-mannose had a somewhat greater affinity for the Sf2l cell transporter than D-glucose, implying that the hydroxyl group at the C-2 position is not necessary for strong binding. However, epimerization at the C-4 position of D-glucose (D-galactose) resulted in a dramatic decrease in affinity of the hexose for the Sf2l cell transporter. Such a lowering of affinity might be the result of the involvement of the C-4 hydroxyl in hydrogen bonding. It is therefore suggested that Sf2l cells were found to contain an endogenous sugar transport activity that in several aspects resembles the human HepG2 type glucose transporter, although the insect and human transporters do differ in their affinity for cytochalasin B.

• 대한핵의학회지
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• 제22권1호
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• pp.65-76
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• 1988

High affinity complexes for the tumor were obtained by changing pH and composition in the preparation of $^{99m}Tc-DMSA$. The purpose of this study was to investigate the tumor affinity, and in vitro and in vivo characteristics of these complexes. The results obtained were as follows; 1) Tumor imaging agent was formed successfully at pH $6.0\sim9.0$ and renal imaging agent at pH $2.0\sim5.0$. 2) The serum protein binding of $^{99m}Tc-DMSA$ was $89.1\sim92.8%$ at pH $2.0\sim5.0$ and $11.8\sim30.5%$ at pH $6.0\sim9.0$ respectively, and it was not changed with time. 3) The T 1/2 of tumor affinity complex in blood between 3 and 6 hours after injection was $187{\pm}29$ minutes $(mean{\pm}SD)$. 4) In the blood, the radioactivity was mainly in the plasma, and less than 1% was in the cellular components. 5) In the Walker carcinosarcoma 256 bearing Wistar rats, the radioactivity in the kidney increased, and decreased in the skeleton with time. The radioactivity in the tumor showed the peak in 6 hours after injection and decreased thereafter. 6) In the tumor cell, the radioactivity localized mainly in the cytosol, the soluble fraction of the cytoplasm. This study provides the basic knowledge about tumor affinity and usefulness of $^{99m}Tc-DMSA$ in the diagnosis of malignant disease.

• Journal of Microbiology and Biotechnology
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• 제12권2호
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• pp.196-203
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• 2002

A novel process for urokinase purification was studied using p-aminobenzamidine as the ligand and sepharose 4B as the matrix. The adsorption, washing, and elution conditions were optimized by an unusual method. An adsorption buffer containing 2.5 M NaCl and $1\%$ Tween 80 facilitated the adsorption of urokinase on the affinity media and prevented contaminants from binding to the p-aminobenzamidine affinity gel. It was found that $5\%$ Tween 80 removed most of the contaminants from the affinity column. A 0.2 M glycine elution buffer containing 0.5 M NaCl (pH 3.0) was found to have a strong elution ability with a high recovery and purity of urokinase. A crude urokinase material of231 IU/mg protein from human urine was purified to 124,300 IU/mg protein with a purification factor of 538 and yield of $86.7\%$. As a result, a high purity urokinase was obtained with only a single affinity chromatography step. The purification process was successfully scaled-up to a 2-1 chromatography column. The resulting urokinase eluate could be directly lyophilized, thereby complying with Chinese pharmacopoeia (1995 version) standards.

• Asian Pacific Journal of Cancer Prevention
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• 제16권9호
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• pp.3759-3765
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• 2015

Background: Approaches in disruption of MDM2-p53 interactions have now emerged as an important therapeutic strategy in resurrecting wild type p53 functional status. The present study highlights virtual screening strategies in identification of high affinity small molecule non-peptidic inhibitors. Nutlin3A and RG7112 belonging to compound class of Cis-imidazoline, MI219 of Spiro-oxindole class and Benzodiazepine derived TDP 665759 served as query small molecules for similarity search with a threshold of 95%. The query molecules and the similar molecules corresponding to each query were docked at the transactivation binding cleft of MDM2 protein. Aided by MolDock algorithm, high affinity compound against MDM2 was retrieved. Patch Dock supervised Protein-Protein interactions were established between MDM2 and ligand (query and similar) bound and free states of p53. Compounds with PubCid 68870345, 77819398, 71132874, and 11952782 respectively structurally similar to Nutlin3A, RG7112, Mi219 and TDP 665759 demonstrated higher affinity to MDM2 in comparison to their parent compounds. Evident from the protein-protein interaction studies, all the similar compounds except for 77819398 (similar to RG 7112) showed appreciable inhibitory potential. Of particular relevance, compound 68870345 akin to Nutlin 3A had highest inhibitory potential that respectively showed 1.3, 1.2, 1.16 and 1.26 folds higher inhibitory potential than Nutilin 3A, MI 219, RG 7112 and TDP 1665759. Compound 68870345 was further mapped for structure based pharamacophoric features. In the study, we report Cis-imidazoline derivative compound; Pubcid: 68870345 to have highest inhibitory potential in blocking MDM2-p53 interactions hitherto discovered.

• The Korean Journal of Physiology and Pharmacology
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• 제7권3호
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• pp.131-142
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• 2003

We have studied mutant forms of Kir2.1 in which an aspartate residue (D172), important for gating by intracellular polyamines, is replaced by one of three basic residues (Arg, Lys or His). Such channels are highly selective for $K^+$, but show inward rectification that is a shallow function of voltage compared with that found in wild type. This inward rectification occurs with a reduced affinity for spermine and persists in the absence of polyamines. Though the unitary current-voltage relation shows some inward rectification, it is insufficient to account for that seen under whole cell recording. Channels open and shut under single channel recording, and changes of $P_{open}$ appear to generate inward rectification. In D172H, the reduction in affinity for spermine is greater when His is protonated at low $pH_i$. The effective valency for spermine is reduced from $3.09{\pm}0.07$ in wild type to $1.95{\pm}0.09$ in D172H at $pH_i$ 6.3. In the presence of dual mutants of Kir2.1, where E224 is also replaced, spermine affinity becomes undetectable. However, channels still show inward rectification and open and shut under hyper- and depolarisation, respectively. We suggest that Kir2.1 channel are able to undergo conformation changes; these changes may be important physiologically in generating inward rectification, the normal parameters of which are set by the binding of polyamines such as spermine.

• Journal of Microbiology and Biotechnology
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• 제17권5호
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• pp.728-732
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• 2007

In the present article, a novel fusion expression vector for Escherichia coli was developed based on the pTORG plasmid, a derivative of pET32a. This vector, named pT7MT(GenBank Accession No DQ504436), carries a T7 promoter and it drives the downstream gene encoding Metallothionein 2A(MT2A). There are in-framed multiple cloning sites(MCS) downstream of the MT2A gene. A target gene can be cloned into the MCS and fused to the C-terminal of the MT2A gene in a compatible open reading frame(ORF) to achieve fusion expression. The metal-binding capability of MT2A allows the purification of fusion proteins by metal chelating affinity chromatography, known as $Ni^{2+}$-affinity chromatography. Using this expression vector, we successfully got the stable and high-yield expression of MT2A-GST and MT2A-Troponin I fusion proteins. These two proteins were easily purified from the supernatant of cell lysates by one-step $Ni^{2+}$-affinity chromatography. The final yields of MT2A-GST and MT2A-Troponin I were 30mg/l and 28mg/l in LB culture, respectively. Taken together, our data suggest that pT7MT can be applied as a useful expression vector for stable and high-yield production of fusion proteins.