• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 1995년도 춘계학술대회
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• pp.81-81
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• 1995

It is well known that Src Homology 2(SH2) domain in many intracellular signal transduction proteins is very important. The domain has about 100 amino acid residues and bind phosphotyrosine-containing peptide with high affinity and specificity. Lck SH2 domain is a Src-like, lymphocyte-specific tyrosine kinase. An 11-residue phosphopeptide derived from the hamster polvoma middle-T antigen, EPQp YEEIPIYL, binds with an 1 nM dissociation constant to Lck SH2 domain. And it is known that the phosphotyrosine and isoleucine residues of the peptide are tightly bound by two well-defined pockets on Lck SH2 domain's surface. To investigate the conformational changes during complexation of SH2 domain with phosphopeptide we have performed the molecular dynamics simulation for Lck SH2 domain with peptide and peptide-free form at look in aqueous solution. More than 3000 water molecules were incorporated to solvate Lck SH2 domain and peptide. Periodic boundary condition has been applied in molecular dynamics simulation. Data analysis with the results of that simulation shows that the phosphopeptide makes primary interaction with the Lck SH2 domain at six central residues, The comparison of the complexed and uncomplexed SH2 domain structures in solution has revealed only relatively small change. But the hydrophilic and hydrophobic pockets in the protein surface show the conformational changes in spite of the small structural difference between the complex and peptide-free forms.

• Journal of Animal Science and Technology
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• 제48권5호
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• pp.671-682
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• 2006

본 실험은 산란종계 노계에서 이소플라본과 CPP의 첨가 급여가 종란 생산성 및 후기 난각질에 미치는 영향과 Ca 대사에 미치는 영향을 검토하기 위한 목적으로 실시하였다. 56주령의 Hy-Line Brown 산란종계 암탉 360수와 수탉 36수를 공시하여 사료 내 Ca을 3.3% 및 3.6% 수준으로 하고 이소플라본과 CPP를 각각 0.2% 및 0.5% 수준으로 첨가한 총 6개의 실험사료(3반복)를 5주간 급여하였다. 주별로 사료섭취량을 조사하였고, 산란율과 난중은 매일 조사하였다. 주별로 생산된 종란으로부터 종란율과 부화율을 조사하였다. 실험사료 급여 후 생산된 계란을 반복구별로 수집하여 난각질 및 난각막 내 glycosaminoglycan과 uronic acid 분석에 이용하였다. 실험 종료 시 반복구별로 평균체중이 비슷한 개체를 선발하여 채혈 후 희생시킨 다음 경골을 적출하였다. 채취한 경골은 화학적 조성의 분석을 위한 시료로 이용하였고, 얻어진 혈액에서 화학성분 및 호르몬 분석을 실시하였다.사료섭취량, 난생산성 및 종란율에서는 처리간에 유의한 차이가 없었다. 사료 내 Ca 수준 및 이소플라본 첨가는 난각강도를 각각 유의하게 개선시킨 것으로 나타났으며, CPP의 첨가에 의해서는 특별한 변화가 관찰되지 않았다. 수정율 및 부화율에서도 처리간에 유의한 차이는 없는 것으로 나타났다. 경골강도 및 경골 내 성분 조성에서 사료 내 Ca 수준 및 이소플라본과 CPP의 첨가 효과는 발견되지 않았다. 혈중 Ca, P, estrogen 및 calcitonin 농도 역시 처리간에 차이가 없는 것으로 나타났다. 본 실험에서는 사료 내 Ca 수준의 증가 및 이소플라본 같은 Ca의 이용성에 영향을 미치는 성분을 적절히 활용함으로서 후기 난각질의 개선을 통해 생산성을 향상시킬 수 있을 것으로 사료된다. 그러나 종란 생산성에 대해서는 이소플라본 및 CPP의 첨가가 크게 영향을 미치지 않았다.

• Bulletin of the Korean Chemical Society
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• 제35권3호
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• pp.845-850
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• 2014

The rapid development of shotgun proteomics is paving the way for extensive proteome profiling, while providing extensive information on various post translational modifications (PTMs) that occur to a proteome of interest. For example, the current phosphoproteomic methods can yield more than 10,000 phosphopeptides identified from a proteome sample. Despite these developments, it remains a challenging issue to pinpoint the true phosphorylation sites, especially when multiple sites are possible for phosphorylation in the peptides. We developed the Phospho-UMC filter, which is a simple method of localizing the site of phosphorylation using unique mass classes (UMCs) information to differentiate phosphopeptides with different phosphorylation sites and increase the confidence in phosphorylation site localization. The method was applied to large scale phosphopeptide profiling data and was demonstrated to be effective in the reducing ambiguity associated with the tandem mass spectrometric data analysis of phosphopeptides.

• Molecules and Cells
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• 제23권3호
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• pp.340-348
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• 2007

Although considerable effort has been devoted in the mass spectrometric analysis of phosphorylated peptides, successful identification of multi-phosphorylated peptides in enzymatically digested protein samples still remains challenging. The ionization behavior of multi-phosphorylated peptides appears to be somewhat different from that of mono- or di-phosphorylated peptides. In this study, we demonstrate increased sensitivity of detection of multi-phosphorylated peptides of beta casein without using phosphopeptide enrichment techniques. Proteinase K digestion alone increased the detection limit of beta casein multi-phosphorylated peptides in the LC-MS analysis almost 500 fold, compared to conventional trypsin digestion (~50 pmol). In order to understand this effect, various factors affecting the ionization of phosphopeptides were investigated. Unlike ionizations of phosphopeptides with minor modifications, those of multi-phosphorylated peptides appeared to be subject to effects such as selectively suppressed ionization by more ionizable peptides and decreased ionization efficiency by multi-phosphorylation. The enhanced detection limit of multi-phosphorylated peptides resulting from proteinase K digestion was validated using a complex protein sample, namely a lysate of HEK 293 cells. Compared to trypsin digestion, the numbers of phosphopeptides identified and modification sites per peptide were noticeably increased by proteinase K digestion. Non-specific proteases such as proteinase K and elastase have been used in the past to increase detection of phosphorylation sites but the effectiveness of proteinase K digestion for multi-phosphorylated peptides has not been reported.

• Bulletin of the Korean Chemical Society
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• 제28권7호
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• pp.1195-1198
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• 2007

• Journal of Dairy Science and Biotechnology
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• 제38권3호
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• pp.161-167
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• 2020

Cheese pizzas fortified with casein phosphopeptide (CPP) and calcium were subjected to an in vitro digestion to assess whether CPP could prevent the precipitation of calcium. The total calcium content of the cheese pizzas was adjusted to 1,000 mg per pizza (~370 g) with the addition of calcium originating from eggshells. Two levels of trypsin-digested caseins (367 and 459 mg), with a CPP content of ~20%, were added to each pizza. The in vitro digested pizzas were then centrifuged and the supernatant was mixed with Na₂HPO₃ at 37℃ to estimate the possible soluble effect of CPP on calcium. After 24 h of reaction, the solution was centrifuged and the calcium content in the resultant supernatant was analyzed by inductively coupled plasma-atomic emission spectroscopy. One-way statistical analyses showed that CPP had a positive effect on the solubilization of calcium against phosphate (p<0.05). Cheese pizza supplemented with 459 mg of CPP powder was able to prevent precipitation of calcium by 98.8%, whereas no CPP-added cheese pizza solubilized 86.4% of the calcium. A sensory test was also carried out, revealing that panelists could not discern the bitter taste of the CPP added to the pizzas.

• 한국치위생학회지
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• 제10권3호
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• pp.473-481
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• 2010

Objectives : To evaluate the effect of fluoride application on the color and microhardness of bleached enamel and compare it to that of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) application. Methods : Twenty freshly extracted human adult molar were each sectioned into halves, the specimens divided and treated according to five experimental groups: Group 1, treatment with 10% carbamide peroxide (CP) bleaching agent; Group 2, treatment with 10% CP followed by a 1.23% fluoride gel application; Group 3, treatment with 10% CP followed by a 2.23% sodium fluoride varnish application; Group 4, treatment with 10% CP followed by a 0.11% sodium fluoride gel application; Group 5, treatment with 10% CP followed by a CPP-ACP gel application. All groups were treated 6 h per day for 14 days then immersed in distilled water for 2 weeks. Changes in enamel color were evaluated on Baseline and Day 14. Microhardness were evaluated on Baseline, Days 7 and 14. Statistical analysis was performed using one-way ANOVA and post-hoc Tukey tests. Results : All the bleached enamel specimens revealed increased whiteness and overall color value. Group 1 showed the lowest microhardness values than that of Groups 2, 3, 4 and 5. In all groups, the hardness of tooth after bleaching showed a significant decrease in the microhardness as compared with the one prior to tooth bleaching. The specimens treated with remineralizing agents showed relatively less reduction in enamel microhardness than control group. Conclusions : The addition of fluoride and CPP-ACP did not impede the whitening effect. The use of remineralizing agents during bleaching treatment can significantly enhance the microhardness of bleached enamel.

• 한국환경농학회지
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• 제25권4호
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• pp.371-381
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• 2006

New proteomic techniques have been pioneered extensively in recent years, enabling the high-throughput and systematic analyses of cellular proteins in combination with bioinformatic tools. Furthermore, the development of such novel proteomic techniques facilitates the elucidation of the functions of proteins under stress or disease conditions, resulting in the discovery of biomarkers for responses to environmental stimuli. The ultimate objective of proteomics is targeted toward the entire proteome of life, subcellular localization biochemical activities, and the regulation thereof. Comprehensive analysis strategies of proteomics can be classified into three categories: (i) protein separation via 2-dimensional gel electrophoresis (2-DE) or liquid chromatography (LC), (ii) protein identification via either Edman sequencing or mass spectrometry (MS), and (iii) proteome quantitation. Currently, MS-based proteomics techniques have shifted from qualitative proteome analysis via 2-DE or 2D-LC coupled with off-line matrix assisted laser desorption ionization (MALDI) and on-line electrospray ionization (ESI) MS, respectively, toward quantitative proteome analysis. In vitro quantitative proteomic techniques include differential gel electrophoresis with fluorescence dyes. protein-labeling tagging with isotope-coded affinity tags, and peptide-labeling tagging with isobaric tags for relative and absolute quantitation. In addition, stable isotope-labeled amino acids can be in vivo labeled into live culture cells via metabolic incorporation. MS-based proteomics techniques extend to the detection of the phosphopeptide mapping of biologically crucial proteins, which ale associated with post-translational modification. These complementary proteomic techniques contribute to our current understanding of the manner in which life responds to differing environment.

• BMB Reports
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• 제34권6호
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• pp.537-543
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• 2001

In the present study, an in vitro ELISA system to assess the interaction between Src homology (SH)2 domains and phosphotyrosine that contain peptides was established using purified GST-conjugated SH2 proteins and synthetic biotinylated phosphotyrosine that contain oligopeptides. The SH2 domains bound the relevant phosphopeptides that were immobilized in the streptavidin-coated microtiter plate in a highly specific and dose-dependent manner. The epidermal growth factor receptor (EGFR)-, T antigen (T Ag)-, and platelet-derived growth factor receptor (PDGFR)-derived phosphopeptides interacted with the growth factor receptor binding protein (Grb)2/SH2, Lck/SH2, and phosphatidyl inositol 3-kinase (PI3K) p85/SH2, respectively. No cross-reactions were observed. Competitive inhibition experiments showed that a short phosphopeptide of only four amino acids was long enough to determine the binding specificity. Optimal concentrations of the GST-SH2 fusion protein and phosphopeptide in this new ELISA system for screening the binding blockers were chosen at 2nM and 500nM, respectively. When two candidate compounds were tested in our ELISA system, they specifically inhibited the Lck/SH2 and/or p85/SH2 binding to the relevant phosphopeptides. Our results indicate that this ELISA system could be used as an easy screening method for the discovery of specific binding blockers of protein-protein interactions via SH2 domains.

• 대한소아치과학회지
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• 제41권3호
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• pp.218-224
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• 2014

이 논문은 법랑질의 표면미세경도와 QLF의 ${\Delta}F$ 값의 변화를 분석하여 5% 불화나트륨을 함유한 고분자 접착 테잎(NaF-PVA)이 법랑질의 재광화에 미치는 영향을 평가하고자하였다. 시편을 탈회한 후 표면미세경도가 평균 50-100 KHN의 범위를 갖고 QLF의 ${\Delta}F$ 값이 -25에서 -15 범위를 갖는 60개의 시편들을 4그룹으로 나누었다 : 그룹1(대조군), 그룹2(NaF-PVA), 그룹3(불소바니쉬, FluoroDose$^{(R)}$ varnish), 그룹4(Casein phosphopeptide-amorphous calcium phosphate, Tooth mousse plus$^{TM}$). 시편들에 각 제제들을 적용하고 인공타액(artificial saliva)에 담근 후 표면미세경도계와 정량 광 형광기를 이용하여 재광화율을 측정하였다. 그 결과 불소를 함유한 고분자 접착 테잎(NaF-PVA)은 그룹1과 4보다 뛰어나며 그룹3과 견줄만한 재광화 효과를 나타냈다 (p<0.05).