理想的胰岛素晶体

在自然界或实验室内 ,“理想化”总是一个难以实现的概念 .但最近美国休斯顿大学的P .Vekilov教授及其同事们发现 ,他们常常可以将胰岛素晶体生长成理想的晶体形式 .他们让胰岛素蛋白质在一个已有的胰岛素晶体的螺旋位错缺陷处进行生长 ,蛋白质将绕着这个缺陷发生晶化并形成一个理想晶状胰岛素 .这是因为螺旋位错常常使晶层间产生一个微小的角度偏差 .对于大多数的晶体来说 ,晶层间的相互作用能促进晶体生长时界面间的配置 ,并导致晶层阶跃发生束缚和形成一个有条纹的晶体 .除此之外 ,在溶液中输入被溶解物质也能引起晶层阶跃的约束 .胰岛…     

细胞色素C的电化学行为研究

本文评述了细胞色素Ｃ电化学研究的发展概况，重点介绍了细胞色素Ｃ在促进剂作用下的电化学行为，促进剂种类，影响促进作用的因素及促进机理。     

带肝细胞受体结合区的HBV表面抗原蛋白性质的研究——preS区有不同缺失的表面抗原蛋白性质的比较

本文用聚合酶链反应(PCR)构建了四对preS区有缺失突变的乙型肝炎病毒表面抗原基因。对这些突变体及我们以前构建的缺失突变体在哺乳动物细胞中的表达和产物性质进行了比较,结果表明,preS区的部分缺失并不影响羧端S区的基本结构和氨端preS区的表面分布性。当缺失preS1区滞留顺序(a.a.2—19)后,preS区对S区带主要抗原决定簇的区域的掩蔽明显减弱。我们发现过长的preS区严重影响表面抗原蛋白从哺乳动物细胞中的分泌,除已知的滞留顺序外,preS1的另一区域(a.a.48—65)可能也有阻滞表面抗原蛋白分泌的作用,而preS2区对LS蛋白分泌的阻滞不起主要作用。preS1的肝细胞受体结合区(a.a.21—47)和S区直接融合所得蛋白性质稳定,分泌良好,有很强的抗preS1抗原性,是值得发展为新型疫苗的带preS1肝细胞受体结合区的表面抗原蛋白。     

胰岛素样生长因子-1对血管平滑肌细胞PI3K／PTEN信号通路的影响

目的：探讨胰岛素样生长因子-1(IGF-1)促血管平滑肌细胞(VSMC)增殖的细胞内信号转导机制。方法：体外培养的兔血管平滑肌细胞分3组处理，以细胞计数、噻唑盐比色法测定细胞增殖能力，以磷脂酰肌醇-3激酶(PI3K)特异性抑制剂渥漫青霉素(WT)孵育细胞间接反映PI3K作用。Western Blot定量磷酸酶PTEN表达水平，免疫沉淀、特异底物diC16PIP3绿色试剂法测定PTEN脂质磷酸酶活性。结果：IGF-1(100μg／L)使细胞计数及MTT比色A值分别增加至对照组的2．8倍和3．8倍，WT抑制VSMC增殖，并完全逆转IGF-1的作用(均P<0.01)。各浓度IGF-1对PTEN蛋白表达水平无明显影响，其对PTEN活性的抑制呈浓度(10～100μg／L)及时间(3min～24h)依赖性(均P<0．01)。结论：IGF-I促VSMC增殖作用与活化PI3K蛋白激酶的促生长活性及抑制PTEN脂质磷酸酶的负性调节细胞生长作用有关。     

Synthesis and Insulin—sensitizing Activity of a Series of 2—Benzyl—1,3—dicarbonyl Derivatives

A series of 2-benzyl-1,3-dicabonyl derivatives was synthesized.Their insulin-sensitizing activity was evaluated in 3T3-L1 preadipocyte cells.Compounds3,26 and 27 were found to possess strong insulin-sensitizing activity in vitro and were selected for further hypoglycemic evaluation in vivo.     

Dependence of Elution Curve and Adsorption Isotherms of Insulin on composition of Mobile Phase of Frontal Analysis in Reversed Phase Liquid Chromatography

With frontal analysis(FA),the dependence of adsorption isotherms of insulin on the composition of mobile phase in reversed phase liquid chromatography (RPLC) has been investigated,This is also a good example to employ the stoichiometric displacement theory (SDT) for ivestigating solute adsorption in physical chemistry.Six kinds of mobile phase in RPLC were employed to study the effects on the elution curves and adsorption isotherms of insulin.the key points of this paper are:(1) the stability of insulin due to delay time after preparing,the organic solvent concentration,the kind and the concentration of ion-pairing agent in mobile phase were found to affect both elution curve and adsorption isotherm very seriously.(2)To obtain a valid and comparable result,the composition of the mobile phase employed in FA must be as same as possible to that in usual RPLC of either analytical scale or preparative purpose.(3)Langmuir Equation and the SDT were employed to imitate these obtained adsorption isotherms.The expression for solute adsorption from solution of the SDT was found to have a better elucidation to the insulin adsorption from mobile phase in RPLC.     

三氟化硼引发四氢呋喃聚合的研究——Ⅳ.1,4-丁二醇的影响

前报中已证明用三氟化硼-环氧氯丙烷(ECH)引发四氢呋喃(THF)聚合具有较高的引发效率,并对在Ac_2O、水和无水存在下的聚合反应进行了研究。本文报道1,4-丁二醇(BG)对BF_3引发THF聚合反应的影响。通常认为在BG存在下,BF_3是不能引发THF聚合的,但本工作证明BG是有效的分子量调节剂,制备分子量在     

高效液相色谱法测定橡胶促进剂TBBS

采用反相高效液相色谱法（HPLC）测定了橡胶促进剂N－叔丁基－2－苯并噻唑次磺酰胺（TBBS）的纯度，标准偏差小于0．3。     

Chemoenzymatic Synthesis of Cellular Adhesion Tripeptide RGD Precursor in Organic Media

IntroductionA characteristic tripeptide sequence Arg-Gly-Asp(RGD) that is found within fibronectin and other rela-ted adhesion molecules in extracellular matrices(ECM)has received considerable attention from researcherssince it was proved to be a recognit…