7 results on '"Kang Hwa Kim"'
Search Results
2. Screening Molecular Chaperones Similar to Small Heat Shock Proteins in Schizosaccharomyces pombe
- Author
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Ji Young Han, Song Mi Lee, and Kang Hwa Kim
- Subjects
Snz1 ,α-Crystalline domain ,Chaperone ,Biology ,Cofilin ,biology.organism_classification ,Microbiology ,NTF2 ,Co-chaperone ,Infectious Diseases ,Biochemistry ,Chaperone (protein) ,Schizosaccharomyces pombe ,Hsp33 ,biology.protein ,Chemical chaperone ,Wos2 ,Small Heat-Shock Proteins ,Small heat-shock proteins ,Research Article - Abstract
To screen molecular chaperones similar to small heat shock proteins (sHsps), but without α-crystalline domain, heat-stable proteins from Schizosaccharomyces pombe were analyzed by 2-dimensional electrophoresis and matrix assisted laser desorption/ionization time-of-flight mass spectrometry. Sixteen proteins were identified, and four recombinant proteins, including cofilin, NTF2, pyridoxin biosynthesis protein (Snz1) and Wos2 that has an α-crystalline domain, were purified. Among these proteins, only Snz1 showed the anti-aggregation activity against thermal denaturation of citrate synthase. However, pre-heating of NTF2 and Wos2 at 70℃ for 30 min, efficiently prevented thermal aggregation of citrate synthase. These results indicate that Snz1 and NTF2 possess molecular chaperone activity similar to sHsps, even though there is no α-crystalline domain in their sequences.
- Published
- 2015
3. Quantitative Detection of Cow Milk in Goat Milk Mixtures by Real-Time PCR
- Author
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Kang Hwa Kim, Deok-Young Jhon, Youn Ho Hong, and Yu Kyung Jung
- Subjects
food.ingredient ,Detection threshold ,12s rrna ,food and beverages ,Biology ,Raw milk ,Cow milk ,fluids and secretions ,Real-time polymerase chain reaction ,food ,Milk products ,Skimmed milk ,Animal Science and Zoology ,Food science ,Food Science - Abstract
The objective of this study was to develop a fluorogenic real-time PCR-based assay for detecting and quantifying amounts of cow milk in cow/goat milk mixtures or goat milk products. In order to quantify the exact amount of cow milk in cow/goat raw milk mixtures and commercial goat milk products, it was necessary to achieve quantitative extraction of total genomic DNA from the raw milk matrix. Both mammalian-specific PCR and cow-specific PCR were performed. A cow-specific 252 bp band obtained from the raw cow milk and raw goat milk mixtures, commercial goat milk, and two goat milk powders was identified, along with the relationship between the cow milk amount and band intensity of the electrophoresis image. The detection threshold was found to be 0.1%. The expression of cow's 12S rRNA in the cow/goat milk mixtures, commercial goat milk, and two goat milk powders was identified. The expression quantity of the milk 12S rRNA increased with increasing ratios of the cow/goat milk mixtures. Using these calibrated relative expression levels as a standard curve in the cow/goat raw milk mixtures, the contents of cow milk were 1.8% in the commercial goat milk, 9.6% in goat milk powder A, and 11.6% in goat milk powder C. However, cow milk was not detected in goat milk powder B.
- Published
- 2011
4. Cyclophilin A Binds to Peroxiredoxins and Activates Its Peroxidase Activity
- Author
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Young S Hwang, Yong Jun Kim, Ho Zoon Chae, Ki Sun Kwon, Hyung Jung Kim, Kang Hwa Kim, and Sang Pil Lee
- Subjects
Time Factors ,Protein Conformation ,Blotting, Western ,Ascorbic Acid ,Biochemistry ,Antioxidants ,Catalysis ,Dithiothreitol ,Cyclophilin A ,chemistry.chemical_compound ,Escherichia coli ,Animals ,Humans ,Cysteine ,Binding site ,Lung ,Molecular Biology ,Binding Sites ,Dose-Response Relationship, Drug ,biology ,Chemistry ,Binding protein ,Peroxiredoxins ,Cell Biology ,Molecular biology ,Recombinant Proteins ,Rats ,Enzyme Activation ,Peroxidases ,Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization ,Cyclosporine ,biology.protein ,Thioredoxin ,Peroxiredoxin ,Peroxiredoxin VI ,Protein Binding ,Subcellular Fractions ,Peroxidase - Abstract
Six distinct peroxiredoxin (Prx) proteins (Prx I-VI) from distinct genes have been identified in mammalian tissues. Prxs are members of a group of peroxidases that have conserved reactive cysteine residue(s) in the active site(s). An immediate physiological electron donor for the peroxidase catalysis for five Prx proteins (Prx I-V) has been identified as thioredoxin (Trx), but that for Prx VI (1-Cys Prx) is still unclear. To identify an immediate electron donor and a binding protein for Prx VI, we performed a Prx VI protein overlay assay. A 20-kDa binding protein was identified by the Prx VI protein overlay assay with flow-through fractions from a High-Q column with rat lung crude extracts. Using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF) and MS-Fit, we identified the 20-kDa Prx VI-binding protein as a cyclophilin A (CyP-A). The binding of recombinant human CyP-A (hCyP-A) to Prx VI was confirmed by using the hCyP-A protein overlay assay and Western immunoblot analysis with hCyP-A-specific antibodies. hCyP-A enhanced the antioxidant activity of Prx VI, as well as the other known mammalian Prx isotypes. hCyP-A supported antioxidant activity of Prx II and Prx VI both against thiol (dithiothreitol)-containing metal-catalyzed oxidation (MCO) systems and ascorbate-containing MCO systems. Prx II was reduced by hCyP-A without help from any other reductant, and the reduction was cyclosporin A-independent. These results strongly suggest that CyP-A not only binds to Prx proteins but also supports its peroxidase activity as an immediate electron donor. In addition, Cys(115) and Cys(161) of hCyP-A were found to be involved in the activation and the reduction of Prx.
- Published
- 2001
5. Methimazole as an antioxidant and immunomodulator in thyroid cells: mechanisms involving interferon-gamma signaling and H(2)O(2) scavenging
- Author
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Mi Ae Bang, Heung Kyu Ro, Kyung-Kwang Lee, Tae Hoon Lee, Dae-Yeul Yu, Young Hwang, Ho Kim, Kang Hwa Kim, O-Yu Kwon, Hyo Kyun Chung, Minho Shong, and Jae Mi Suh
- Subjects
endocrine system diseases ,Thyroid Gland ,Gene Expression ,Suppressor of Cytokine Signaling Proteins ,Antioxidants ,Drug Interactions ,STAT1 ,Phosphorylation ,Cells, Cultured ,Janus kinase 2 ,Janus kinase 1 ,Thyroid ,Protein-Tyrosine Kinases ,Intercellular Adhesion Molecule-1 ,Protein Inhibitors of Activated STAT ,DNA-Binding Proteins ,medicine.anatomical_structure ,STAT1 Transcription Factor ,Peroxidases ,Molecular Medicine ,Signal Transduction ,STAT3 Transcription Factor ,endocrine system ,Biology ,Electron Transport ,Interferon-gamma ,Suppressor of Cytokine Signaling 1 Protein ,Adjuvants, Immunologic ,Proto-Oncogene Proteins ,medicine ,Animals ,Pharmacology ,Methimazole ,Proteins ,Hydrogen Peroxide ,Janus Kinase 1 ,Peroxiredoxins ,Janus Kinase 2 ,Rats ,Repressor Proteins ,Kinetics ,Suppressor of Cytokine Signaling 3 Protein ,Protein Biosynthesis ,STAT protein ,Cancer research ,biology.protein ,Trans-Activators ,Tyrosine ,Peroxiredoxin ,Janus kinase ,Carrier Proteins ,Hormone ,Transcription Factors - Abstract
The antithyroid drug, methimazole (MMI) is used to treat patients with Graves' hyperthyroidism. The major action of MMI is to inhibit synthesis of thyroid hormone in the thyroid gland. However, MMI also has antioxidant and immunomodulatory effects on thyrocytes and/or immune cells. This study identifies novel antioxidant and immunomodulatory effects of MMI involving the interferon-gamma (IFN-gamma) signaling pathway in thyroid cells. MMI inhibits transcription of the intercellular adhesion molecule-1 (ICAM-1) gene by modulating the function of transcription factor STAT1 (signal transducer and activator of transcription 1), which binds to the IFN-gamma activated site of the ICAM-1 promoter. Furthermore, MMI rapidly eliminates H(2)O(2) produced by IFN-gamma treatment in thyroid cells and thus inhibits the H(2)O(2)-mediated phosphorylation of tyrosine 701 in STAT1. MMI also eliminates H(2)O(2) in vitro. MMI facilitates electron transfer from NADPH to H(2)O(2) using thioredoxin or glutathione, fulfilling a role similar to peroxiredoxin or glutathione peroxidase, respectively. MMI prevents the IFN-gamma and H(2)O(2)-mediated reversible inactivation of phosphatases. These effects inhibit full activation of the IFN-gamma-induced Janus kinase(JAK)/STAT signaling pathway in FRTL-5 thyroid cells. These results may in part explain the antioxidant and immunomodulatory effects of MMI in thyroid cells of Graves' disease patients.
- Published
- 2001
6. Sequence of peptides from Saccharomyces cerevisiae glutamine synthetase. N-terminal peptide and ATP-binding domain
- Author
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Sue Goo Rhee and Kang Hwa Kim
- Subjects
chemistry.chemical_classification ,biology ,Saccharomyces cerevisiae ,Structural gene ,Peptide ,Cell Biology ,biology.organism_classification ,Biochemistry ,Homology (biology) ,Yeast ,Glutamine ,Enzyme ,chemistry ,Glutamine synthetase ,Molecular Biology - Abstract
Sequences of seven tryptic peptides derived from Saccharomyces cerevisiae glutamine synthetase have been determined. The amino terminus of yeast enzyme is acetylated and has the following sequence: acetyl-Ala-Glu-Ala-Ser-Ile-Glu-Lys. Neither higher eukaryotic nor bacterial glutamine synthetase contain sequences homologous to this yeast amino terminus. 8-Azidoadenosine 5'-triphosphate [( alpha-32P]8-N3ATP) has been used to photolabel the ATP-binding site in yeast glutamine synthetase. Only one 32P-labeled tryptic peptide was obtained as a major fraction and its sequence is Glu-Gly-Tyr-Gly-X-Phe-Glu-Asp-Arg. Similar photolabeling experiments with bovine glutamine synthetase yielded a tryptic peptide whose sequence is Gly-X-Phe-Glu-Asp-Arg, where X is likely Tyr covalently attached by nitrene derived from [alpha-32P]8-N3ADP. Sequences very homologous to this nucleotide-binding site can be found in other eukaryotic enzymes but not in prokaryotic enzymes. In addition, the sequences of two cysteine-containing peptides and three other tryptic peptides were established. Sequences homologous to all these five peptides can be found in mammalian and plant enzymes. The homology between yeast and higher eukaryotic glutamine synthetases was sufficiently strong to suggest that the overall tertiary and quaternary structures of these enzymes must be similar. The sequences presented here, particularly the amino terminus sequence will be valuable in identifying the structural gene of yeast glutamine synthetase, thereby making it possible to study its transcriptional regulation. In addition, the sequences of the cysteine-containing peptides will be useful in determining whether or not the covalent modification of a sulfhydryl group(s) is responsible for the modulation of glutamine synthetase activity.
- Published
- 1988
7. Subunit interaction elicited by partial inactivation with L-methionine sulfoximine and ATP differently affects the biosynthetic and gamma-glutamyltransferase reactions catalyzed by yeast glutamine synthetase
- Author
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Sue Goo Rhee and Kang Hwa Kim
- Subjects
chemistry.chemical_classification ,biology ,Protein subunit ,Saccharomyces cerevisiae ,Glutamate receptor ,Cell Biology ,biology.organism_classification ,Biochemistry ,Yeast ,Divalent ,chemistry.chemical_compound ,Enzyme ,chemistry ,Glutamine synthetase ,Molecular Biology ,Adenosine triphosphate - Abstract
Yeast glutamine synthetase can be irreversibly inactivated in the presence of L-methionine sulfoximine, ATP, and a divalent cation Mn2+ or Mg2+. Kinetic studies with partially inactivated enzymes show that inactivation of a given subunit in the octameric glutamine synthetase affects the activities of its neighboring subunit such that the rate of the inactivation as well as the gamma-glutamyltransferase activity of the noninactivated subunits decreases while their biosynthetic activity is enhanced. This outcome of subunit interaction is the same irrespective of whether Mn2+ or Mg2+ is used to fulfill the divalent cation requirement of glutamine synthetase for the inactivation reaction and the gamma-glutamyltransferase reaction. Although only Vmax is affected in the gamma-glutamyltransferase assay, both Km (glutamate) and Vmax are changed in the biosynthetic assay.
- Published
- 1987
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