Multimerization of Peptide Mimotopes for Blocking of Factor VIII Neutralizing Antibodies

About 30 % of patients with severe hemophilia A develop neutralizing antibodies (inhibitors) to coagulation factor VIII (FVIII) upon treatment with exogenous factor preparations. Two peptides, C6 (NPVENMMDRDSQ) and H10 (QSPWQTWFTRAL), that mimic putative inhibitor epitopes (mimotopes), were previously selected by phage display screening of plasma samples from patients with inhibitors. Synthetic peptide mimotopes inhibited IgG binding to FVIII (IC₅₀: 30–50 μM ). This effect was increased by an equimolar combination of both mimotopes. Mimotopes were fused to the C‐terminal multimerization domain of the C4bp α‐chain and expressed as multimers in 293T cells. Multimerized mimotopes showed improved binding to anti‐FVIII IgG and prolonged in vitro half‐life relative to synthetic peptides. The two mimotopes were combined in heteromultimers by co‐transfection of 293T cells with respective vectors, resulting in bi‐specific molecules that almost completely blocked polyclonal antibody binding to FVIII (IC₅₀: 2–3 μM ). This strategy is capable of functionally improving synthetic peptides by multimerization and could provide a basis for novel therapeutic approaches for patients with hemophilia A and inhibitors.     

以NiSO_4/γ-Al_2O_3为催化剂丙烯齐聚制十二烯和十八烯工艺的研究

以NiSO4/γ-Al2O3为催化剂,采取连续串联两段反应器的工艺,对丙烯齐聚合成十二烯和十八烯的工艺条件进行了研究。考察了温度、液态空速对丙烯转化率和目的产物选择性的影响。实验结果表明,最佳工艺条件为:压力2.0MPa、液态空速1.0h-1、第一段反应温度10℃、第二段反应温度80℃。在此反应条件下,丙烯总转化率达到97%以上,十二烯和十八烯的选择性分别达到52.84%和10.41%,且催化剂的稳定性好。     

Isolation and mapping of self-assembling protein domains encoded by the Saccharomyces cerevisiae genome using lambda repressor fusions

Understanding how proteins are able to form stable complexes is of fundamental interest from the perspective of protein structure and function. Here we show that lambda repressor fusions can be used to identify and characterize homotypic interaction domains encoded by the genome of Saccharomyces cerevisiae, using a selection for polypeptides that can drive the assembly of the DNA binding domain of bacteriophage lambda repressor. Three high complexity libraries were constructed by cloning random fragments of S. cerevisiae DNA as lambda repressor fusions. Repressor fusions encoding homotypic interactions were recovered, identifying oligomerization units in 35 yeast proteins. Seventeen of these interaction domains have not been previously reported, while the other 18 represent homotypic interactions that have been characterized at varying levels of detail. The novel interactions include several predicted coiled-coils as well as domains of unknown structure. With the availability of genomic sequences it should be possible to apply this approach, which provides information about protein-protein interactions that is complementary to that obtained from yeast two-hybrid screens, on a genome-wide scale in yeast or other organisms where large-scale protein-protein interaction data is not available.     

惰性组分对异丁烯齐聚反应的影响

以正已烷为惰性组分 ,利用高压反应釜实验装置研究了不同惰性组分添加量对异丁烯齐聚反应的影响 ,得到了惰性组分对异丁烯齐聚反应转化率、产物分布、齐聚反应级数的影响规律     

Catalytic Oligomerization of ethylene over nano-sized HZSM-5

The nano-sized HZSM-5 zeolites with different Si/Al ratios were pretreated, characterized, and tested in ethylene oligomerization performed in a fixed-bed reactor under relatively mild conditions. The effects of catalyst acidity and reaction temperature on the activity, selectivity and stability were investigated, and a possible reaction route of ethylene over acidic sites of nano-sized HZSM-5 catalyst was proposed. In comparison with micro-sized HZSM-5 zeolite, nano-sized HZSM-5 zeolites exhibited higher activity and better resistance to deactivation. Under optimal conditions (T = 275–300 °C, P = 3.0 MPa, WHSV = 1.0 h⁻¹), The average ethylene conversion was 62.5% over the nano-sized HZSM-5 with an Si/Al ratio of 80, while the selectivity to C₄₊ olefins and α-olefins was 64.3% and 13.3%, respectively. Furthermore, the products of ethylene oligomerization were a complex hydrocarbon mixture due to the acid-catalyzed secondary reactions, for which the distribution of even and odd numbered carbon atoms formed a continuous volcanic shape mainly centered on C₆–C₁₀. Furthermore, these tests demonstrate that the activity and selectivity of ethylene oligomerization depend on the operating conditions and the acidity of the catalysts. These results indicate that the Brønsted acid sites may be mainly responsible for secondary reactions and deactivation of the catalyst, whereas the Lewis acid sites may be more advantageous for ethylene oligomerization.     

硅藻土磷酸盐催化剂酸性及对丙烯齐聚的催化作用

游离磷酸作为硅藻土磷酸盐固体酸催化剂, 用于催化丙烯齐聚和其他反应。采用了离子色谱 （ Ｉ Ｃ）、 Ｈａｍ ｍ ｅｔｔ ｐ Ｈ 指示剂法和 Ｎａ Ｏ Ｈ 溶液化学滴定法, 研究了催化剂中游离磷酸的数量和组成与催化剂活性的关系。结果表明, 游离磷酸由 ５％ —３５％ 正磷酸 （ Ｈ３ Ｐ Ｏ４）、１％ —７％ 焦磷酸 （ Ｈ４ Ｐ２ Ｏ７） 和＜ １％ 的多聚磷酸组成。它直接影响催化剂的酸强度分布。含有 ８％ —１５％ Ｈ３ Ｐ Ｏ４和 ２％ —５％ Ｈ４ Ｐ２ Ｏ７ 的催化剂具有一定数量的中、高强度酸中心, 故其丙烯齐聚催化活性高。     

异丁烯齐聚固定床反应器的模拟

利用高压微反实验装置，在排除了外扩散影响的基础上，利用集总的方法建立了异丁烯齐取反应集总动力学模型，并对该模型进行了求解，获得了该反应集总宏观动力学方程；对φ30mm的固定床反应器建立了一维拟均相模型，结合集总动力学方程对该反应器进行了模拟，实验结果与模拟结果吻合，证明动力学模型与反应器模型是可行的。     

焙烧温度对HZSM-5分子筛催化1-丁烯齐聚性能的影响

考察焙烧温度对HZSM-5分子筛催化剂结构及1-丁烯齐聚性能的影响,采用XRD、SEM和NH3-TPD对催化剂进行表征。结果表明,升高焙烧温度,对HZSM-5分子筛催化剂的晶相和晶粒尺寸没有影响,催化剂中弱酸与强酸的酸强度和酸量均随焙烧温度的升高逐渐减弱。在催化剂晶粒尺寸一定条件下,催化剂酸性对催化剂的齐聚性能有较大影响,焙烧温度500℃时,C5+收率和C10+选择性最佳。     

双环戊二烯加压连续聚合制备高能量密度燃料

为制备密度大于1 g·ml^-1的高密度燃料母体化合物三环戊二烯（TCPD）,研究了双环戊二烯（DCPD）的加压连续聚合反应。分析了聚合反应产物组成和反应途径,研究了反应条件的影响。与常压间歇反应相比,加压连续反应能极大地提高反应转化率和收率,优化产物组成,TCPD中挂式/桥式（exo/endo）比例大大提高,并生成新的产物exo-DCPD。反应途径分析表明,TCPD中exo/endo比例与exo-DCPD选择性呈线性正相关。研究发现,为维持反应进行压力应不低于1.2 MPa,增加温度能提高反应转化率,而TCPD最高收率出现在160℃,TCPD的exo/endo比例随温度增加而降低,反应转化率和收率随停留时间增加而增加,但转化速率降低,缩短停留时间有利于提高TCPD的exo/endo比例,浓度对反应影响不大。在较优条件下,endo-DCPD转化率达82.2%,TCPD收率达41.7%。     

Oligomerizing Olefins in Light Coke Gasoline to Diesel

We prepare a catalyst for FCC gasoline polymerizing to produce diesel oil, which uses non-noble metal Ni as the main active component; here mesopore γ-Al₂O₃ is used as the carrier. The effects of mass fraction of active components and the condition of preparing were investigated simultaneously. The results show that mass fraction of the main active component is 8%, soakage time is 6 hr, and the roasting temperature is 500°C to roast for 4 hr, which are better conditions for preparing the catalyst. Under the condition of a reaction temperature of 210°C, reaction pressure is 3.0 Mpa, space velocity is 1.0 h^-1, and volumetric percent of diesel is 42.0%, which meet a criterion of -35^# diesel. At the same time we study the stability and regeneration of the catalyst with good results.