• 한국식품영양과학회지
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• 제32권4호
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• pp.645-653
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• 2003

Taste receptor cells respond to gustatory stimuli using a complex arrangement of receptor molecules, signaling cascades and ion channels. When stimulated, these cells produce action potentials that result in the release of neurotransmitter onto an afferent nerve fiber that in turn relays the identity and intensity of the gustatory stimuli to tie brain. A variety of mechanisms are used in transducing the four primary tastes. Direct interaction of the stimuli with ion channels appears to be of particular importance in transducing stimuli reported as salty or sour, whereas tile second messenger systems cyclic AMP and inositol trisphosphate are important in transducing bitter and sweet stimuli. In addition to the four basic tastes, specific mechanisms exist for the amino acid glutamate, which is sometimes termed the fifth primary taste. The emerging picture is that not only do individual taste qualities use more than one mechanism, but multiple pathways are available for individual tastants as well.

• BMB Reports
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• 제29권3호
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• pp.248-252
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• 1996

The epidermal organ of the leech contains a complex glycoprotein molecule of mucus. The mucus excreted from annelids plays Significant role in protection against desiccation and parasites. Mucus from the Korean native leech, H. nipponia, was investigated for biochemical characteristics for possible development of biomaterials of cosmetic and pharmaceutical agents. The leech skin mucus was heavily glycosylated mucin-like protein with a high molecular weight comprised 80% carbohydrate and 20% protein. Threonine, serine, and glycine were the major components of the isolated protein and these accounted for 50% of total amino acids. The carbohydrate portion contained glucosamine, galactosamine. galactose, glucose. mannose and sialic acid in oligosaccharide form linked with threonine and serine residues of the glycoprotein.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제10권4호
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• pp.314-318
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• 2010

Predicting Alpha-helicies, Beta-sheets and Turns of a proteins secondary structure is a complex non-linear task that has been approached by several techniques such as Neural Networks, Genetic Algorithms, Decision Trees and other statistical or heuristic methods. This project introduces a new machine learning method by combining Bayesian Inference with offline trained Multilayered Perceptron (MLP) models as the likelihood for secondary structure prediction of proteins. With varying window sizes of neighboring amino acid information, the information is extracted and passed back and forth between the Neural Net and the Bayesian Inference process until the posterior probability of the secondary structure converges.

• BMB Reports
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• 제41권3호
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• pp.177-183
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• 2008

Ubiquitin is an essential, highly-conserved small regulatory protein in eukaryotic cells. It covalently modifies a wide variety of targeted proteins in the forms of monomer and polymers, altering the conformation and binding properties of the proteins and thus regulating proteasomal delivery, protein activities and localization. Mass spectrometry has emerged as an indispensable tool for in-depth characterization of protein ubiquitination. Ubiquitinated proteins in cell lysates are usually enriched by affinity chromatography and subsequently analyzed by mass spectrometry for identification and quantification. Ubiquitin-conjugated amino acid residues can be determined by unique mass shift caused by the modification. Moreover, the complex structure of polyubiquitin chains on substrates can be dissected by bottom-up and middle-down mass spectrometric approaches, revealing potential novel functions of polyubiquitin linkages. Here I review the advances and caveats of these strategies, emphasizing caution in the validation of ubiquitinated proteins and in the interpretation of raw data.

• BMB Reports
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• 제41권3호
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• pp.194-203
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• 2008

Nitrosative modifications regulate cellular signal transduction and pathogenesis of inflammatory responses and neuro-degenerative diseases. Protein tyrosine nitration is a biomarker of oxidative stress and also influences protein structure and function. Recent advances in mass spectrometry have made it possible to identify modified proteins and specific modified amino acid residues. For analysis of nitrated peptides with low yields or only a subset of peptides, affinity 'tags' can be bait for 'fishing out' target analytes from complex mixtures. These tagged peptides are then extracted to a solid phase, followed by mass analysis. In this review, we focus on protein tyrosine modifications caused by nitrosative stresses and proteomic methods for selective enrichment and identification of nitrosative protein modifications.

• International Journal of Industrial Entomology and Biomaterials
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• 제10권2호
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• pp.125-129
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• 2005

Ribosome-associated membrane protein 4 (RAMP4) is a membrane protein that exposes its N-terminal hydrophilic portion on the cytoplasmic side and spans the membrane close to the C-terminal end. RAMP4 has previously been reported to belong to the set of proteins that remains associated with membrane-bound ribosomes, and controls the glycosylation of major histocompatbility complex class II-associated invariant chain. RAMP4 also may be relative to the stabilization of membrane proteins in response to stress, with other components of translocon, and molecular chaperons in ER. Application of 5'-RACE technique with specially designed primer, we cloned a 715 bp cDNA fragment which contains a 195 bp ORF, termed RAMP4. The deduced protein has 64 amino acid residues and contains a putative transmembrane-spanning domain at the COOH terminus.

• 미생물학회지
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• 제15권3호
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• pp.131-138
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• 1977

The effects of various nitrogen soruces on the expression of nif gene were investigated using nif-lac fusants of Klebsiella pneumoniae. K. pneumoniae UK 2979 was infected with Mudl lysate prepared by heat induction of K. pneumoniae UK 4482. About 80 nif-lac fusants were greatly repressed. Amino acids, such as serine, glutamine and asparagine, were found to support the growth of K. pneumoniae M5al quite well, and showed a repressive effect on .betha.-galactosidase activities of nif-lac fusants LX-9 and LX-22 in NFHM. Glutamic acid, histidine and arginine rendered poor growth but high activities of .betha.-galactosidase. Good cell growth and high enzyme activity were observed when complex nitrogen sources, such as casitone, proteose pepone, were employed. .betha.-Galactosidase activities of LX-9 and LX-22 in nitrogen free minimal medium increased sharply within first 4 hours.

• Archives of Pharmacal Research
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• 제17권5호
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• pp.337-342
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• 1994

Carbohydrate analysis is important in studying structure and activity of complex polysaccharides. New analytical method was applied to get an information on the composition of polysaccharides showing antitumor activity. Monosaccharides were labeled with 7-amino-1, 3-naph-thalenedisulfonic acid (7-AGA) by reductive amination and separated by HPLC. Five kinds of polysaccharides from Basidiomycetes were hydrolyzed and analyzed in combination with electrophresis and HPLC. At the same time, alditol acetate derivatives were prepared and analyzed by gas chromatography. Two different techniques using different derivatization methods showed very similar results. The monosaccharides from Coriolus versicolor and Cordyceps militaris were glucose and galactose. Phellinus linteus composed of glucose, glactose, mannose, arabinose and fucose. The HPLC method with fluorescence detector was very sensitive compared to other methods.

• 한국생물물리학회:학술대회논문집
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• 한국생물물리학회 2002년도 제9회 학술 발표회 프로그램과 논문초록
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• pp.54-54
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• 2002

$\sigma$$\^$R/ is a sigma factor responsible for inducing the thioredoxin system in response to oxidative stress in Streptomyces coelicolor. RsrA, an anti-sigma factor, specifically binds to $\sigma$$\^$R/ and inhibits $\sigma$$\^$R/-directed transcription under reducing conditions. Exposure to H$_2$O$_2$ or thiol-specific oxidant diamide dissociates $\sigma$$\^$R/-RsrA complex. The redox-dependent regulation of $\sigma$$\^$R/-RsrA binding has been reported to involve thiol-disulfide exchange in RsrA, which contains 7 cysteines in 105 amino acid residues.(omitted)

• 통합자연과학논문집
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• 제10권1호
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• pp.20-26
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• 2017

Chemerin receptor, which predominantly expressed in immune cells as well as adipose tissue, was found to stimulate chemotaxis of dendritic cells and macrophages to the site of inflammation. Chemerin is a widely distributed multifunctional secreted protein implicated in immune cell migration, adipogenesis, osteoblastogenesis, angiogenesis, myogenesis, and glucose homeostasis. Recent studies suggest chemerin may play an important role in the pathogenesis of obesity and insulin resistance and it becomes a potential therapeutic target for treating type II diabetes. The crystal structure of chemerin receptor has not yet been resolved. Therefore, in the present study, homology modelling of CMKLR1 was done utilizing the crystal structure of human angiotension receptor in complex with inverse agonist olmesartan as the template. Since the template has low sequence identity, we have incorporated both threading and comparative modelling approach to generate the three dimensional structure. 3D models were generated and validated. The reported models can be used to characterize the critical amino acid residues in the binding site of CMKLR1.