• Bulletin of the Korean Chemical Society
• /
• v.32 no.spc8
• /
• pp.2997-3002
• /
• 2011

A series of hybrid molecules between (R)-lipoic acid (ALA) and the acetylated or methylated polyphenol compounds were synthesized and their in vitro cholinesterase [acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE)] inhibition activities were checked. The $IC_{50}$ values of all hybrid molecules for a BuChE inhibition were lower than those of the single parent compounds. Specifically, ALA-acetyl protected caffeic acid (11, ALA-AcCA) was shown as an effective inhibitor of BuChE ($IC_{50}=0.5{\pm}0.2\;{\mu}M$) and also had a great selectivity for BuChE over AChE (more than 800 fold). Inhibition kinetic study indicated that 11 is a mixed inhibition type. Its binding affinity ($K_i$) value to BuChE is $1.52{\pm}0.18\;{\mu}M$.

• Asian Pacific Journal of Cancer Prevention
• /
• v.15 no.19
• /
• pp.8155-8159
• /
• 2014

Background: Breast cancer is the serious health concern in India causing the highest mortality rate in females, which occurs due to uncontrolled cell division and can be metastasize to other parts of the human body. Interactions with estrogen receptor (ER) alpha are mainly responsible for the malignant tumors with regulation of the transcription of various genes as a transcription factor. Most of the drugs currently used for the breast cancer treatment produce various side effects and hence we focused on natural compounds which do not exhibit any toxic effect against normal human cells. Materials and Methods: Structure of human ER was retrieved from the Protein Data Bank and the structures of flavonoid compounds have been collected from PubChem database. Molecular docking and drug likeness studies were performed for those natural compounds to evaluate and analyze the anti-breast cancer activity. Results: Finally two compounds satisfying the Lipinski's rule of five were reported. The two compounds also exhibited highest binding affinity with human ER greater than 10.5 Kcal/mol. Conclusions: The results of this study can be implemented in the drug designing pipeline.

• 한국생물공학회:학술대회논문집
• /
• 2001.11a
• /
• pp.197-203
• /
• 2001

A fusion protein, consisting of human epidermal growth factor as a recognition domain and human angiogenin as a toxin domain, can be used as a targeted therapeutic against breast cancer cells among others. The fusion protein was expressed as inclusion body in recombinant E. coli, and when the conventional, solution-phase refolding process was used the refolding yield was very low due to severe aggregation, probably due to the opposite surface charge due to vastly different pI values of each domain. Solid-phase refolding process exploiting ionic interactions between the solid matrix and the protein was tried, but the ionic binding yield was very low regardless of the resins and pH conditions used. To provide higher affinity toward the solid matrix, six lysine residues were tagged to the N -terminus of the hEGF domain When the cation exchange resins such as heparin- or CM-Sepharose were used as the matrix, the adsorption capacity increased 2.5-3 times and the subsequent refolding yield increased nearly IS times compared to the conventional process.

• KSBB Journal
• /
• v.7 no.4
• /
• pp.302-307
• /
• 1992

Protein phosphatase 2A was obtained from a cytosolic fraction of bovine brain homogenate. The phosphatase activity using phosphorylated histone Hl as substrate was suppressed in the presence of liposomes composed of dipalmitoylphosphatidylcholine(DPPC) or the mixture of phosphatidylserine and DPPC. The binding of protein phosphatase to liposome was indicated by the facts that the phosphatase activity of the supernatant of protein phosphatase/multilayer vesicle mixture was decreased with increasing amount of liposome, and that [$^{125}I$]-labeled protein phosphatase was coeluted with liposome. However, the affinity of the protein for phospholipid membrane was not so high. On the other hand, okadaic acid and liposome reduced the phosphatase activity synergistically, which means that okadaic acid binds neither to lipid membrane nor to the membrane-associated phosphatase, The inhibitory effect of liposome was, therefore, ascribed to association of the protein phosphatase 2A with the lipid bilayer membrane.

• BMB Reports
• /
• v.30 no.3
• /
• pp.205-210
• /
• 1997

p53 tumor suppressor plays an important role in the regulation of cellular proliferation. To identify proteins regulating the expression of p53 in rat liver, we analyzed p53 promoter by electrophoretic mobility shift assay (EMSA) and DNase I footprinting assay. We found that a protein binds the sequence CACGTG, bHLH consensus sequence in rat p53 promoter. Southwestern blotting analysis with oligonucleotides containing this sequence shows that the molecular weight of the protein is 100 kDa. This size is not compatible with the bHLH family such as USF or c-Myc/Max which is known to regulate the expression of the human and mouse p53 gene. Therefore this 100 kDa protein may be a new protein regulating basal transcription of rat p53. We purified this 100 kDa protein through sequence-specific DNA affinity chromatogaphy.

• BMB Reports
• /
• v.42 no.12
• /
• pp.817-822
• /
• 2009

Type-1 phosphatase (PP-1) was assessed in foot muscle (FM) and hepatopancreas (HP) of estivating (EST) Otala lactea. Snail PP-1 displayed several conserved traits, including sensitivity to inhibitors, substrate affinity, and reduction in size to a 39 kDa catalytic subunit (PP-1c). During EST, PP-1 activity in FM and HP crude extracts was reduced, though kinetics and protein levels of purified PP-1c isoforms were not altered. PP-1c protein levels increased and decreased in nuclear and glycogen-associated fractions, respectively, during EST. Gel filtration determined that a 257 kDa low $K_m$ PP-1$\alpha$ complex decreased during estivation whereas a 76 kDa high $K_m$ complex increased in EST. Western blotting confirmed that the 76 kDa protein consisted of PP-1$\alpha$ and nuclear inhibitor of PP-1 (NIPP-1). A suppression of PP-1 activity factors in the overall metabolic rate depression in estivating snails and the mechanism is mediated through altered cellular localization and interaction with binding partners.

• Journal of Nutrition and Health
• /
• v.28 no.10
• /
• pp.1022-1030
• /
• 1995

Saponins are glycosidic compounds present in many plant foods. They are characterized by their ability to lyse cell membranes due to their surface-active properties. Saponins are believed to interact primarily with cholesterol in the cell membrane. In this study, the interaction of soybean(SS) with cell membrane was investigated using erythrocytes as a model. Mechanisms of interaction was also investigated by measuring their binding capacity with different membrane lipid fractions. Throughout the study, gypsophilla saponin(GS) and quillaja saponin(QS) were used to evaluate the membranolytic activity of soybean saponins. All saponins released hemoglobin in a concentration-dependent manner. SS induced 40% hemolysis at the concentration of 400 ppm, however there was no increase in hemoglobin release above 400ppm concentration. 5ppm of GS and 8 ppm of QS hemolyzed 100% of erythrocytes. Isolation of SS fractions by thin layer chromatography revealed that only one non-polar saponin possesses strong hemolytic activity. When saponins were incubated decreased the release of cholesterol. When the hemolytic activity of saponins was measured in the presence of other major membrane lipid components, sphingomyelin significantly reduced the hemolytic activity of SS, while cholesterol reduced the activity of QS. GS showed high affinity to other component(s) in the incubation media as well as lipids. These results suggest that the membranolytic activity of saponins are related to their specific chemical structure, which determines the interaction behavior between saponins and different membrane components, and thereby influence the biological activity.

• BMB Reports
• /
• v.38 no.6
• /
• pp.717-724
• /
• 2005

The nontoxic B subunit of cholera toxin (CTB) can significantly increase the ability of proteins to induce immunological tolerance after oral administration, when it was conjugated to various proteins. Recombinant CTB offers great potential for treatment of autoimmune disease. Here we firstly investigated the feasibility of silkworm baculovirus expression vector system for the cost-effective production of CTB under the control of a strong polyhedrin promoter. Higher expression was achieved via introducing the partial non-coding and coding sequences (ATAAAT and ATGCCGAAT) of polyhedrin to the 5' end of the native CTB gene, with the maximal accumulation being approximately 54.4 mg/L of hemolymph. The silkworm bioreactor produced this protein vaccine as the glycoslated pentameric form, which retained the GM1-ganglioside binding affinity and the native antigenicity of CTB. Further studies revealed that mixing with silkworm-derived CTB increases the tolerogenic potential of insulin. In the nonconjugated form, an insulin : CTB ratio of 100 : 1 was optimal for the prominent reduction in pancreatic islet inflammation. The data presented here demonstrate that the silkworm bioreactor is an ideal production and delivery system for an oral protein vaccine designed to develop immunological tolerance against autoimmune diabetes and CTB functions as an effective mucosal adjuvant for oral tolerance induction.

• BMB Reports
• /
• v.38 no.6
• /
• pp.676-682
• /
• 2005

To date, no 8-oxoguanine-specific endonuclease-coding gene has been identified in Thermotoga maritima of the order Thermotogales, although its entire genome has been deciphered. However, the hypothetical protein Tm1821 from T. maritima, has a helix-hairpin-helix motif that is considered to be important for DNA binding and catalytic activity. Here, Tm1821 was overexpressed in Escherichia coli and purified using Ni-NTA affinity chromatography, protease digestion, and gel filtration. Tm1821 protein was found to efficiently cleave an oligonucleotide duplex containing 8-oxoguanine, but Tm1821 had little effect on other substrates containing modified bases. Moreover, Tm1821 strongly preferred DNA duplexes containing an 8-oxoguanine:C pair among oligonucleotide duplexes containing 8-oxoguanine paired with four different bases (A, C, G, or T). Furthermore, Tm1821 showed AP lyase activity and Schiff base formation with 8-oxoguanine in the presence of $NaBH_4$, which suggests that it is a bifunctional DNA glycosylase. Tm1821 protein shares unique conserved amino acids and substrate specificity with an 8-oxoguanine DNA glycosylase from the hyperthermophilic archaeon. Thus, the DNA recognition and catalytic mechanisms of Tm1821 protein are likely to be similar to archaeal repair protein, although T. maritima is an eubacterium.

• Proceedings of the Korean Society of Dyers and Finishers Conference
• /
• 2012.03a
• /
• pp.29-29
• /
• 2012

Rhodamine chromophore/fluorophore have been attracted to many researchers due to its excellent photophysical properties. In this study, we have designed and synthesized a strong emissive fluorescent dye chemosensor for toxic elements. A rhodamine-based sensor was prepared by incorporation the rhodamine fluorophore and several functional host groups with high affinity to hazardous metal and anion. This sensor shows a high selectivity and an excellent sensitivity and is a dual-responsive colorimetric and fluorescent metal/anion-specific sensor. In addition, the 1:1 binding mode was proposed based on Job's plot method. Finally, computational calculation was simulated and calculated to approach for HOMO/LUMO of this dye chemosensor.