• 약학회지
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• 제39권5호
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• pp.516-520
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• 1995

The anti-dansyl antibodies were specifically labeled with stable isotope by growing hybridoma cells in serum-free medium. Assignments of the observed carbonyl carbon resonances have been determined by using $^{13}C-{15}N$ double labeling method in order to assign the Leu resonances. However, when the identical dipeptide appears more than twice in the polypeptide sequences, we applied the proteolytic fragments in the fragment-specific method. Carboxypep-tidase B-treated antibody has also been used to assign the Lys-447 in C terminal amino acid. These unambiguously assigned carbonyl carbon resonances in antibodies are thought to be useful in elucidating not only the structure of antibodies but also the structure-function relationship in the antibody by $^{13}C$ neuclear magnetic resonance spectroscopy.

• Bulletin of the Korean Chemical Society
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• 제19권2호
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• pp.189-193
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• 1998

Carboxypeptidase-B (CPB) is involved in the biosynthesis of numerous peptide hormones and neurotransmitters. CPB catalyzes hydrolysis of the basic amino acids from the C-terminal position in polypeptides during posttranslational prohormonal processing. Various peptides containing thiaarginine residue at C-terminal position were synthesized and tested for their hydrolysis by CPB. A colorimetric assay, employing Ellman's reagent to detect the thioguanidine released upon hydrolysis of the dipeptide substrates, showed that thiaarginine is a suitable mimetic for arginine. Kinetic studies on the four substrates, Z-L-Ala-DL-thia-Lys, Z-L-Ala-DL-thia-Arg, Z-L-Lys-DL-thia-Arg, and Z-L-Lys(Boc)-DL-thia-Arg, gave Km (mM) of 0.66, 5.08, 0.024, and 0.006 and kcat (min-1) of 340, 5200, 151 and 335, respectively.

• 대한화학회지
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• 제51권4호
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• pp.318-323
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• 2007

양성자가 결합된 티로신-알라닌 펩타이드 이온(YAH+)의 전자전이 광분해 스펙트럼을 이 이온의 가 장 낮은 에너지의 전자전이가 관측되는 34500~36700 cm-1 영역에서 얻었다. YAH+ 이온은 전자분무 이온화법 을 이용하여 기체상에서 생성하였고 생성된 이온의 저장 및 검출은 4중극자 이온 트랩과 반사판 비행시간 질 량분석기가 결합된 혼성 질량분석기를 이용하였다. 이온 트랩에 저장된 YAH+ 이온에 레이저 펄스를 쪼여주어 광분해 반응을 유발한 후 그 광분해 정도를 레이저 파장에 따라 측정함으로써 전자전이 광분해 스펙트럼을 얻 었다. 이 스펙트럼에는 두 개의 넓은 폭을 가진 피크가 관측되었으며 시간-의존 밀도함수 법(Time-dependent density functional method, TD-DFT)을 이용한 계산을 통해 각각 YAH+의 S1과 S2 전이로 지정하였다. 관측된 피 크들의 넓은 폭은 상온에서 존재 가능한 YAH+의 여러 이형태체들의 전자전이 간 겹침과 또한, 상온에서 형성 된 이온의 들뜬 진동에너지 준위로부터의 전자전이 즉, 뜨거운 띠(hot band)들 때문인 것으로 설명하였다.

• 대한수의학회지
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• 제34권4호
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• pp.857-866
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• 1994

톡소플라즈마 과면역(過免疫) 우혈청(牛血淸)에서 유래된 면역증강제인 obioactin으로 처리한 마우스 복강 macrophages내(內)에서의 톡소플라즈마 증식억제 활성을 검토하였다. obioactin 및 lonomycin A로 처리한 macropohages에서는 첨가농도의 증가에 따라 세포내의 톡소플라즈마 증식이 현저하게 억제되었다. 그러나 macrophages 활성물질인 muramyl dipeptide(MDP)는 톡소플라즈마의 증식억제 효과가 없었다. 이와같이 obioactin 및 lonomycin A의 첨가에 의해 macrophages내(內)에서 톡소플라즈마의 증식이 억제되는 기전의 일부를 해명하기 위한 일환으로 활성산소 중간체 및 lysozyme 분비량을 검토하였다. obioactin과 MDP로 처리한 macrophages에서는 활성산소 중간체인 superoxide anion($O_2{^-}$)과 hydropen peroxide($H_2O_2$)의 생산은 첨가농도에 의존해서 증가하였으나 lonomycin A 첨가군에서는 대조군과 차이가 없었다. 한편 세포내에서 분비되는 lysozyme의 양은 obioactin, lonomycin A 및 MDP를 첨가한 각각의 macrophages에서 첨가농도의 증가에 따라 무처지 대조군에 비해 감소되었다. 이러한 결과로 부터 obioactin은 macrophages를 활성화시켜 세포내에서 활성산소 중간체($O_2{^-}$ 및 $H_2O_2$)를 발생시켜 이것들에 의해 톡소플라마즈의 증식이 억제되는 것으로 사료되었다. 그러나 macrophages내에서 분비되는 lysozyme은 톡소플라즈마의 증식억제와는 무관하였다.

• 생명과학회지
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• 제8권4호
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• pp.410-415
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• 1998

HPLC 및 electrospary mass spectrum으로부터 L-L dipeptide의 존제하에서 pepsin은 hexapeptide인 L-S-pNF-Nle-A-OMe를 가수분해하여 가수분해물외의 새로운 생성물을 합성하는 것이 확인되었다. 이 생성물은 254nm에서 p-nitro-Phe 잔기를 포함하는 peptide였다. 실험결과로부터 E(L-S-pNF)와 L-L 사이의 acyl transpeptidation에 의해 L-S-pNF-L-L가 생성됨을 뒷받침한다. 이러한 transpeptidation 결과는 product 저해실험에 의한 결과에 기초한 것과는 반대로 L-S-pNF가 해리되기전에 Nle-A-L-OMe가 먼저 한다는 것을 보여준다. 그리고, electrospray mass spectrum 으로부터 위에서 검출된 새로운 펩티드에 해당하는 peak (MW 636.1)을 얻었는데, 이는 새 펩티드의 생성을 확실히 증명하는 증거이다. 한편, Nle-A-L-OMe 생성에 대한 solvent isotope effect는 1.736$\pm$0.121이며 L-S-pNF는 2.28$\pm$0.184 그리고 L-S-pNF-L-L의 생성에는 inverse isotope effect로서 0.576$\pm$0.045였는데, 이는 상기 생성물 해리 순서를 확인시켜 준다. D$_{2}$에서 transpeptidation은 더 빠르기 때문에 isotopically-sensitive단계는 Nle-A-L-OMe해리후에 존재하는 것을 알 수 있다. 본 실험결과는, Rebholz and Northrop$^{1)}$ 및 Cho등의 $^{2)} iso-mechanism이론의 타당성을 제시한다.

• 한국축산식품학회지
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• 제34권1호
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• pp.127-132
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• 2014

Optimization of carnosine and anserine extraction from chicken breast was performed using response surface methodology (RSM) to obtain the maximized physiological activities for anti-glycation and anti-oxidation. The optimum extraction conditions were water extraction for 1.6 h in the case of the 20-wk laying hen muscle and water extraction for 2.12 h in the case of 90-wk laying hen muscle. Higher carnosine and anserine contents were measured in the 20-wk laying hen muscle, along with higher physiological activities, which increased in direct proportion with the dipeptide contents. The extracts prepared from the 20-wk laying hen under optimum conditions showed 57% inhibition of advanced glycated end-product formation, 64% inhibition of lipid peroxidation, and 61% of DPPH radical scavenging effects. On the other hand, 52% inhibition of AGE formation, 62% inhibition of lipid peroxidation, and 53% of DPPH radical scavenging effect were demonstrated within the 90-wk laying hen. In addition, the ratio of carnosine was a key indicator for the physiological activities of the extracts.

• BMB Reports
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• 제45권2호
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• pp.114-119
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• 2012

Salsolinol (1-methyl-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline) is a compound derived from dopamine metabolism and is capable of causing dopaminergic neurodegeneration. Oxidative modification of neurofilament proteins has been implicated in the pathogenesis of neurodegenerative disorders. In this study, oxidative modification of neurofilament-L (NF-L) by salsolinol and the inhibitory effects of histidyl dipeptides on NF-L modification were investigated. When NF-L was incubated with 0.5 mM salsolinol, the aggregation of protein was increased in a time-dependent manner. We also found that the generation of hydroxyl radicals (${\bullet}OH$) was linear with respect to the concentrations of salsolinol as a function of incubation time. NF-L exposure to salsolinol produced losses of glutamate, lysine and proline residues. These results suggest that the aggregation of NF-L by salsolinol may be due to oxidative damage resulting from free radicals. Carnosine, histidyl dipeptide, is involved in many cellular defense processes, including free radical detoxification. Carnosine, and anserine were shown to significantly prevent salsolinol-mediated NF-L aggregation. Both compounds also inhibited the generation of ${\bullet}OH$ induced by salsolinol. The results indicated that carnosine and related compounds may prevent salsolinol-mediated NF-L modification via free radical scavenging.

• 한국생물정보학회:학술대회논문집
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• 한국생물정보시스템생물학회 2000년도 International Symposium on Bioinformatics
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• pp.32-34
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• 2000

Computational chemistry is a discipline using computational methods for the calculation of molecular structure, properties, and reaction or for the simulation of molecular behavior. Relating and turning the complexity of data from genomics, high-throughput screening, combinatorial chemical synthesis, gene-expression investigations, pharmacogenomics, and proteomics into useful information and knowledge is the primary goal of bioinformatics. In particular, the structure-based molecular design is one of essential fields in bioinformatics and it can be called as structural bioinformatics. Therefore, the conformational analysis for proteins and peptides using the techniques of computational chemistry is expected to play a role in structural bioinformatics. There are two major computational methods for conformational analysis of proteins and peptides; one is the molecular orbital (MO) method and the other is the force field (or empirical potential function) method. The MO method can be classified into ab initio and semiempirical methods, which have been applied to relatively small and large molecules, respectively. However, the improvement in computer hardwares and softwares enables us to use the ab initio MO method for relatively larger biomolecules with up to v100 atoms or ∼800 basis functions. In order to show how computational chemistry can be used in structural bioinformatics, 1 will present on (1) cis-trans isomerization of proline dipeptide and its derivatives, (2) positional preference of proline in ${\alpha}$-helices, and (3) conformations and activities of Arg-Gly-Asp-containing tetrapeptides.

• 한국식품영양학회지
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• 제26권1호
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• pp.117-124
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• 2013

근내지방도(IMF)가 한우육의 품질 및 기능성분에 미치는 영향을 조사하기 위하여, 250두의 한우를 근내지방 함량에 따라 Low(<14%, n=96), Medium(14~17%, n=83), High(>17%; n=71) 세 그룹으로 분류하고, 7일간 숙성 후 등심육의 품질 및 기능성분을 분석하였다. 한우 등심육의 수분 함량은 IMF와 반비례하였으며, High IMF 그룹은 Low IMP 그룹에 비하여 낮은 드립 감량을 나타내었다. 기능성 didpeptide 함량은 IMF에 따라 유의적 차이가 없었으나, High IMF 그룹은 다른 그룹보다 낮은 inosine monophosphate, 높은 hypoxanthine, 낮은 histidine 함량은 나타내었다. 불포화지방산의 비율은 IMF에 따라 유의적 차이가 없었다. 저지방육의 건강지향적 가치를 고려할 때 지나친 IMF를 목표로 하는 육종 및 사양은 지양되어야 할 것으로 판단되었다.

• Biomolecules & Therapeutics
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• 제16권4호
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• pp.356-363
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• 2008

A bacterial strain with good antibacterial activities against Staphylococus aureus and Escherichia coli was isolated from a marine sponge Stelleta sp., and it was identified as a Psychrobacter sp. by comparative 16S rDNA sequence analysis. In our search for bioactive secondary metabolites from this psychrophillic and halotolerent bacterium, sixteen cyclic dipeptides (1-16) were isolated and their structures were identified on the basis of NMR analysis. In the test of the compounds for the protective effect against Vibrio vulnificusinduced cytotoxicity in human intestinal epithelial cells, cyclo-(L-Pro-L-Phe) (5) exhibited significant protective effect. Compounds 2, 6, and 11, which contain D-amino acid, were first isolated from bacteria.