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  • 【论文】 dPPA对阿尔茨海默病相关蛋白FURIN的基因调控研究

    作者:查静思 关键词:阿尔茨海默病 ; 弗林蛋白酶 ; 中药单体 ; 佛波酯类蛋白激酶C激动剂 机构:重庆医科大学 ; 重庆医科大学 年份:2016
    摘要:Furin作为一种前体蛋白转化酶,可促进神经营养因子的转化成熟,保护神经细胞、对抗内质网/氧化应激损害;并可能通过影响APP代谢、自噬等机制参与AD的发生和发展。为研究furin在AD中的潜在作用,我们构建携带了人furin P1启动子的荧光素酶报道基因质粒,稳定转染细胞后进行中药单体高通量药物扫描,发现4种佛波酯类PKC激动剂能有效促进furin P1荧光素酶活性。选取其中两种不致癌的dPA、d PPA进行研究,发现它们均能增加furin的mRNA和蛋白水平的表达。通过对furin的基因调控分析,发现dPA、dPPA并非通过TGFβ信号通路、蛋白磷酸化信号通路参与对furin的调控;而PKC抑制剂calphostin C能有效阻断dPA、dPPA对furin表达的促进作用,提示是它们通过PKC蛋白质的相互作用介导了furin基因的表达调控。已知furin P1的调控元件包括CEBPβ和GATA1,我们将furin P1截断为若干片段,分别转染细胞并用4种PKC激动剂处理,找到荧光素酶活性表达强度最高的片段,并对其进行核酸序列和调控元件分析,发现该片段可能包含调控元件CEBPβ的结合位点序列。用si-RNA分别抑制CEBPβ和GATA1表达后,发现dPPA主要通过CEBPβ参与furin基因的调控。
  • 【期刊】 DPPA催化芴-9-羧酸的新颖脱羧反应

    刊名:化学试剂 作者:丛晓丽 ; 倪帅帅 ; 朱进 关键词:DPPA ; 芴-9-羧酸 ; 脱羧反应 机构:华东理工大学药学院 ; 华东理工大学药学院 ; 民生药业滨江分公司 年份:2012
    摘要:以0.096 mmol叠氮磷酸二苯酯(Diphenylphosphorazidate,DPPA)为催化剂,在极性溶剂和0.48 mmol的三乙胺存在的条件下,0.48 mmol芴-9-羧酸可以发生新颖的脱羧反应。考察了水、有机溶剂以及不同物质的量的DPPA和三乙胺对反应收率的影响。并针对反应结果,提出了可能的反应机理,即:反应中芴-9-羧酸形成的碳负离子可以被结构中的五元环稳定,亲核进攻DPPA形成六元环状过渡态,并发生分子内消除反应,得到脱羧产物。
  • 【期刊】 高效液相色谱法测定叠氮磷酸二苯酯(DPPA)的含量

    刊名:郑州大学学报(工学版) 作者:赵建宏 ; 李磊 ; 武红旗 ; 王留成 ; 宋成盈 关键词:高效液相色谱 ; 叠氮磷酸二苯酯 ; 相转移催化 机构:郑州大学化工学院 ; 郑州大学化工学院 ; 郑州大学化工学院 ; 郑州大学化工学院 ; 郑州大学化工学院 ; 郑州大学化工学院 年份:2008
    摘要:采用高效液相色谱法,紫外检测器(检测波长254 nm),在C18(150 mm×4.6 mm i.d.)色谱柱上,以V(甲醇)∶V(水)=70∶30为流动相,对由氯代磷酸二苯酯和叠氮钠为原料,相转移催化法合成的DPPA进行定量分析.结果表明,该方法的相对标准偏差为0.3%,平均回收率99.60%,线性相关系数为0.999 9.
  • 【期刊】 膜脂分子DPPA的喇曼谱退偏比的测量

    刊名:光谱学与光谱分析 作者:贾惟义 ; 孙永泰 机构:中国科学院物理研究所 ; 中国科学院物理研究所 ; 中国科学院生物物理研究所 年份:1987
    摘要:提出了利用90度旋光器测量喇曼散射退偏比的两种方法,并利用这些方法测量了膜脂分子DPPA的偏振喇曼谱。根据退偏比的大小,振动模分属于三种类型:全对称、部分对称和不对称振动。对有关振动模的归属进行了初步的讨论。
  • 【期刊】 Diphenylphosphoryl Azide (DPPA) - A Reagent with Manifold Applications

    刊名:Synlett 作者:Liang ; Huan 年份:2008
    摘要:http://www.thieme-connect.de/DOI/DOI?10.1055/s-2008-1067132
  • 【期刊】 Role of the Escherichia coli Hfq protein in GcvB regulation of oppA and dppA mRNAs

    刊名:Microbiology 作者:Pulvermacher, S. C. ; Stauffer, L. T. ; Stauffer, G. V. 年份:2009
    摘要:http://mic.sgmjournals.org/cgi/doi/10.1099/mic.0.023432-0
  • 【期刊】 Miscibility of DPPC and DPPA in monolayers at the air/water interface

    刊名:Chemistry and Physics of Lipids 作者:I. Estrela-Lopis ; G. Brezesinski ; H. M?hwald 年份:2004
    摘要:Monolayers of mixtures of 1,2-dipalmitoylphosphatidylcholine (DPPC) as the substrate and 1,2-dipalmitoylphosphatidic acid (DPPA) as the product of the hydrolysis reaction catalyzed by phospholipase D (PLD) were investigated in the presence of Ca2+. The miscibility behavior and the microstructure of mixed domains have been studied by gracing incidence X-ray diffraction (GIXD), Brewster angle microscopy and film balance measurements. The phase diagram reveals partial miscibility on both sides and a wide miscibility gap, which becomes narrower at high pressure. At low pressure, the segregation of condensed DPPA-rich domains in a fluid-like DPPC matrix was detected already at small DPPA concentrations and their structure was determined. A small amount of DPPC mixed into the segregated DPPA domains induces the transformation from rectangular to an oblique unit cell and increases the tilt angle in the condensed domains. At high pressure, two types of condensed phase domains were found: DPPC-rich and DPPA-rich. A drastic reduction of the tilt angle in the DPPC-rich domains with increasing amount of DPPA was observed. The decrease of the tilt angle must be connected with a change of the head group conformation of DPPC in such mixed domains. Copyright 2004 Elsevier Ireland Ltd. All rights reserved.
  • 【期刊】 New Cu(i) and Ag(i) binuclear complexes containing the dppa ligand

    刊名:Journal of the Chemical Society, Dalton Transactions 作者:Liu, Huizhang ; Jos?? Calhorda, Maria ; Drew, Michael G. B. ; F??lix, Vitor ; Novosad, Josef ; Veiros, Lu??s F. ; Fabrizi de Biani, Fabrizia ; Zanello, Piero 年份:2002
    摘要:http://xlink.rsc.org/?DOI=b205922n
  • 【期刊】 Reliable Protocol for the Large Scale Synthesis of Diphenylphosphoryl Azide (DPPA)

    刊名:Synthesis 作者:Wolff, Oliver ; Waldvogel, Siegfried R. 年份:2004
    摘要:http://www.thieme-connect.de/DOI/DOI?10.1055/s-2004-815965
  • 【期刊】 Organization of collagen in the presence of diphenyl phosphoryl azide (DPPA): An in vitro study

    刊名:Colloids and Surfaces B: Biointerfaces 作者:Usha, R. ; Sreeram, K.J. ; Mandal, A.B. 关键词:Diphenyl phosphoryl azide (DPPA) ; Collagen ; Stabilization ; Organization ; Reconstituted collagen fibrils 年份:2013
    摘要:Collagen, an important fibrous protein and its stability is closely related to organizational order. In this work, organization of collagen in the presence of diphenyl phosphoryl azide (DPPA) was studied using circular dichroic spectroscopy, stress-strain characteristics and fibrillogenesis. The reconstituted collagen fibrils in the presence of DPPA were characterized using Fourier transform infrared spectroscopy, differential scanning calorimetry, X-ray diffraction and polarizing light microscopy. CD spectra show that the secondary structure of the collagen molecule is preserved when the concentrations of DPPA is less than 0.018 mu M. The Increase in shearing stress with shearing speed is 5-8% higher in the presence of DPPA may be due to the rigidity of the collagen chains. DPPA facilitates self assembly processes, thinner fibrils are seen in polarizing light microscopy and seem to favor the molecular and phase structure of collagen. Thermal stability of collagen in the presence of DPPA ensured the integrity and stabilization of reconstituted collagen fibrillar matrices. Collagen fibrils have higher denaturation enthalpy 15 J/gm at 0.5 mu M (DPPA) when compared to 10.5 J/gm for native collagen fibrils which is an indication of more stable fibrils. As a result, the reconstituted collagen fibrils in the presence of DPPA brought about the stabilization of the secondary structure of collagen molecules at lower concentrations of DPPA. (C) 2013 Elsevier B.V. All rights reserved.
  • 【期刊】 Organization of collagen in the presence of diphenyl phosphoryl azide (DPPA): An in vitro study

    摘要:Collagen, an important fibrous protein and its stability is closely related to organizational order. In this work, organization of collagen in the presence of diphenyl phosphoryl azide (DPPA) was studied using circular dichroic spectroscopy, stress-strain characteristics and fibrillogenesis. The reconstituted collagen fibrils in the presence of DPPA were characterized using Fourier transform infrared spectroscopy, differential scanning calorimetry, X-ray diffraction and polarizing light microscopy. CD spectra show that the secondary structure of the collagen molecule is preserved when the concentrations of DPPA is less than 0.018 μM. The Increase in shearing stress with shearing speed is 5-8% higher in the presence of DPPA may be due to the rigidity of the collagen chains. DPPA facilitates self assembly processes, thinner fibrils are seen in polarizing light microscopy and seem to favor the molecular and phase structure of collagen. Thermal stability of collagen in the presence of DPPA ensured the integrity and stabilization of reconstituted collagen fibrillar matrices. Collagen fibrils have higher denaturation enthalpy 15 J/gm at 0.5 μM (DPPA) when compared to 10.5 J/gm for native collagen fibrils which is an indication of more stable fibrils. As a result, the reconstituted collagen fibrils in the presence of DPPA brought about the stabilization of the secondary structure of collagen molecules at lower concentrations of DPPA.