多糖的共价键合对7S球蛋白凝胶性能的影响

引入细胞学说中的大分子拥挤体系并在该体系通过Maillard反应制备了大豆7S球蛋白(b-conglycinin,7S)和葡聚糖(dextran,Dex)的共价复合物,利用转谷氨酰胺酶(transglutaminase,TGase)的交联作用制得蛋白-多糖共价复合物凝胶.对其流变学、质构特性及微结构进行分析.结果表明,在大分子拥挤环境下,7S-葡聚糖比例为2:1的共价复合物制得具有致密且孔洞分布均匀的凝胶网络结构.单纯的蛋白自聚集或者与多糖的共混状态时形成的凝胶弹性模量都较高,但蛋白过度的聚集并不能得到孔洞均匀的凝胶网络结构,共价复合物制备的凝胶中葡聚糖的共价键合作用抑制了TGase交联过程中蛋白质分子间发生过度的相互作用.形貌学观察表明,共价复合物制备的凝胶形成了网络孔径均匀且非常致密的凝胶网络结构.     

多糖的共价键合对7S球蛋白凝胶性能的影响

引入细胞学说中的大分子拥挤体系并在该体系通过Maillard反应制备了大豆7S球蛋白（β-conglycinin,7S）和葡聚糖（dextran,Dex）的共价复合物,利用转谷氨酰胺酶（transglutaminase,TGase）的交联作用制得蛋白-多糖共价复合物凝胶。对其流变学、质构特性及微结构进行分析。结果表明,在大分子拥挤环境下,7S-葡聚糖比例为2：1的共价复合物制得具有致密且孔洞分布均匀的凝胶网络结构。单纯的蛋白自聚集或者与多糖的共混状态时形成的凝胶弹性模量都较高,但蛋白过度的聚集并不能得到孔洞均匀的凝胶网络结构,共价复合物制备的凝胶中葡聚糖的共价键合作用抑制了TGase交联过程中蛋白质分子间发生过度的相互作用。形貌学观察表明,共价复合物制备的凝胶形成了网络孔径均匀且非常致密的凝胶网络结构。     

大豆7S球蛋白与葡聚糖共价键合纳米凝胶的制备与表征

基于蛋白质与多糖的Maillard反应与自组装制备一种新型的绿色的具备核壳结构的纳米凝胶。利用干热反应制备大豆7S球蛋白与葡聚糖的共价接枝物(soy β-conglycinin-dextran conjugates,SDC),通过对SDC热处理使其自组装成大豆7S球蛋白-葡聚糖纳米凝胶(soy β-conglycinin-dextran nanogels,SDN),对其形貌、结构及性质进行分析,并利用多糖的空间位阻效应抑制蛋白质宏观过度聚集的理论指导,探讨尺寸均一SDN的形成机制。形貌学与zeta电位分析表明SDN为具备核壳结构的球状粒子,其外壳由亲水性的葡聚糖构成,内核由凝胶化的蛋白构成;表面疏水性分析表明内核蛋白的三级结构发生转变,疏水基团暴露,从而形成多个疏水空腔;稳定性分析表明SDN具有高度的pH稳定性与储存稳定性,对疏水活性物质的输送载体构建具有重要的借鉴意义。     

大豆7S球蛋白与葡聚糖共价键合纳米凝胶的制备与表征

基于蛋白质与多糖的Maillard反应与自组装制备一种新型的绿色的具备核壳结构的纳米凝胶。利用干热反应制备大豆7S球蛋白与葡聚糖的共价接枝物（soy β-conglycinin-dextran conjugates,SDC）,通过对SDC热处理使其自组装成大豆7S球蛋白-葡聚糖纳米凝胶（soy β-conglycinin-dextran nanogels,SDN）,对其形貌、结构及性质进行分析,并利用多糖的空间位阻效应抑制蛋白质宏观过度聚集的理论指导,探讨尺寸均一SDN的形成机制。形貌学与zeta电位分析表明SDN为具备核壳结构的球状粒子,其外壳由亲水性的葡聚糖构成,内核由凝胶化的蛋白构成;表面疏水性分析表明内核蛋白的三级结构发生转变,疏水基团暴露,从而形成多个疏水空腔;稳定性分析表明SDN具有高度的pH稳定性与储存稳定性,对疏水活性物质的输送载体构建具有重要的借鉴意义。     

酪蛋白酸钠-燕麦β-葡聚糖美拉德产物的制备及其性质

以酪蛋白酸钠（Sodium Caseinate，SC）和燕麦β-葡聚糖(oat β-glucan，OG)利用干法美拉德反应制备酪蛋白酸钠-燕麦β-葡聚糖美拉德产物。利用单因素试验，以接枝度和褐变度为评价指标，对其制备条件进行研究，确定酪蛋白酸钠-燕麦β-葡聚糖美拉德产物最佳反应条件为：酪蛋白酸钠：燕麦β-葡聚糖为1:2，反应温度为60 ℃，反应时间为24 h，反应湿度为78 %，反应pH值为7。SDS-PAGE 电泳结果表明，酪蛋白酸钠和燕麦β-葡聚糖之间共价交联形成大分子聚合物。红外光谱分析表明糖苷键成功连接到蛋白质分子。内源荧光光谱表明引入多糖亲水性羟基，酪蛋白酸钠空间结构改变。最终得到美拉德产物的接枝度为50.01 %，褐变L值为85.06，乳化活性提高了85.12 %，乳化稳定性提高了11.24 %。本文改善了酪蛋白酸钠在一定pH范围内的溶解性和乳化性，拓展了酪蛋白酸钠在食品医药的应用范围。     

壳聚糖-海藻酸钠载药微球的缓释性能研究

采用乳化交联法制备出负载5-氟尿嘧啶(5-Fu)的壳聚糖-海藻酸钠磁性载药微球。利用红外(FIRT)、X射线衍射(XRD)、热重(TG)、紫外-可见分光光度计(UV)对1其进行结构表征和缓释性能研究,考察了不同因素对载药微球缓释性能的影响。结果表明,油水相体积比为1∶1时载药性能最佳,载药量为6.69%,包封率为22.00%,产物发生交联反应且保持原有晶型,同时在不同p H值环境下载药微球相对5-Fu药物有明显的缓释作用,并且在p H=8.4时药物达到最大释放量,微球适用于给肠癌细胞靶向供药。     

DBSA掺杂聚苯胺及其碳纳米管复合物的合成与表征

分别采用乳液聚合法和原位聚合法制备出十二烷基苯磺酸(DBSA)掺杂的聚苯胺和聚苯胺/碳纳米管复合物。使用电子探针、傅里叶变换红外光谱仪、紫外-可见分光光度计、同步热分析仪等对合成的产物进行了表征,并通过化学结构分析了碳纳米管和聚苯胺之间的相互作用。结果表明:聚苯胺分子链上的苯环和醌环的共振频率与碳纳米管发生共轭效应而降低,使得复合物电导率提高了3.69倍;复合物的形成促进了聚苯胺分子链上的醌环与碳纳米管之间的电荷转移,提高了复合物对紫外-可见光的吸收强度和热稳定性。     

明胶/Fe_2S_3纳米生物复合物形成反应的热力学及明胶构象变化

在pH=7.40条件下,采用一锅化学反应法制得水溶性明胶/Fe2S3纳米生物复合物,扫描电镜照片显示Fe2S3颗粒为棒状。根据吸光度与Fe2S3浓度关系,由Benesi-Hildebrand方程计算了不同温度下反应的形成常数K(293K:14.47×102L·mol-1;297K:9.24×102 L·mol-1;309K:1.70×102L·mol-1)及对应温度下反应的热力学参数(ΔrGm=-17.88/-16.68/-13.09kJ·mol-1;ΔrHm=-105.57kJ·mol-1;ΔrSm=-299.28J·K-1·mol-1),结果表明明胶/Fe2S3纳米生物复合物的形成反应是自发的放热过程,且为焓驱动。傅里叶变换红外光谱表明,Fe2S3主要与明胶大分子肽链中的酰胺键结合;对红外光谱进行去卷积拟合,结果表明:明胶蛋白质的α-螺旋含量减少,β-折叠含量明显增加。结合紫外和红外光谱测试结果对复合物的形成机理作了初步的推测:首先Fe3+与明胶大分子中的酰胺键结合形成明胶/Fe3+复合物,然后S2-与明胶/Fe3+中的Fe3+形成明胶/Fe2S3复合物。     

甘氨酸席夫碱(Ni)配合物法不对称合成2S,7S-二氨基辛二酸

以S-2-N-(N′-苄基-S-脯氨酰)-氨基二苯甲酮-镍(Ⅱ)-甘氨酸(BPB-Ni(Ⅱ)-Gly)复合物为手性助剂,与1,4-二溴丁烷反应制备了标题化合物.探讨了反应时间以及反应物配比对反应产率影响,确定了最佳反应条件:BPB-Ni(Ⅱ)-Gly复合物与1,4-二溴丁烷的物质的量比为1∶0.5,反应时间为10 min.2S,7S-二氨基辛二酸的总产率为63%.同时用核磁共振、高分辨质谱及旋光技术对产物进行了表征.     

MTG酶诱导大豆11S球蛋白透明冷致水凝胶的制备

水凝胶的制备逐步朝向安全无毒、高生物相容性的方向发展。本工作着重探究一种大豆球蛋白透明冷致水凝胶的制备方法。首先利用葡聚糖硫酸盐（dextran sulphate, DS）与大豆11S球蛋白（glycinin, 11S）在加热过程中形成多阴离子复合物,继而采用微生物转谷氨酰胺酶（microbial transglutaminase, MTG酶）在pH 7.0、一定离子强度条件下,通过分子间ε-（γ-谷氨酰胺基）赖氨酸共价键交联,制备了透明冷致水凝胶,并对其流变学、质构特性、持水性及微结构进行研究。结果表明：葡聚糖硫酸盐（DS）的添加赋予大豆11S球蛋白溶液较高的荷电量,在中性条件下,MTG酶具有交联此高荷电多阴离子复合物的能力,从而在较低温度下形成透明冷致水凝胶。通过控制相似文献   

右旋糖酐-阿司匹林偶联物的合成

以右旋糖酐和乙酰水杨酰氯为原料,合成了高分子偶联物右旋糖酐 阿司匹林,并用FTIR、1HNMR对其结构进行了表征。考察了缚酸剂、右旋糖酐重均相对分子质量、反应温度和物料比对酯化反应的影响。结果表明,三乙胺和吡啶均可作为该酯化反应的缚酸剂,而浓氢氧化钠水溶液则不适合;乙酰水杨酰基的接入率随右旋糖酐重均相对分子质量的增大而减小,但随乙酰水杨酰氯与右旋糖酐的质量比的增加而增大;当选用Mw=20 000的右旋糖酐、缚酸剂三乙胺,反应温度在 60℃左右、m(乙酰水杨酰氯) /m(右旋糖酐 ) =3. 06时,乙酰水杨酰基的接入率和其有效转化率分别为 9. 30%和 3 .07%。     

Plastic performance of soybean protein components

Soybean proteins recently have been considered as petroleum polymer alternatives in the manufacture of adhesives, plastics, and various binders. The objective of this work was to characterize the plastic performance of soybean protein components during molding processes. Two major soybean protein fractions, 7S-rich globulin (7S-RG) and 11S-rich globulin (11S-RG) were separated from defatted soybean flour, and their purity was examined by sodium dodecyl sulfate-polyacrylamide gel eletrophoresis and high-performance liquid chromatography. The thermal transition properties of the two fractions at 10% moisture content were 137.6°C for 7S and 163°C for 11S, as analyzed using differential scanning calorimetry (DSC). Plastics were prepared using a hot press at various molding temperatures that were selected based on the proteins’ thermal transition temperatures obtained by DSC. The plastics were evaluated for mechanical properties, water absorption, and microstructure. The plastics prepared with temperatures at or close to the thermal transition temperature showed a smooth, uniform, and complex structure. Results showed that the plastics made from 11S-RG at its thermal transition temperature were stronger (35 MPa) and had lower water absorption than those made from 7S-RG at 145°C (26 MPa). The plastics made from the 7S- and 11S-RG mixture had the highest tensile strength (39 MPa) and medium water absorption compared to those made from 7S- and 11S-RG alone. These mechanical properties and water absorption behaviors were significantly affected by molding temperatures. The results obtained from this research indicated that interaction between 7S- and 11S-RG could occur during molding and that thermal transition temperature played an important role in thermal processing of soybean proteins.     

Modification of Sodium Lignosulfonate and Evaluation of its Potential Use as Detergent Builders

Sodium lignosulfonate (LS) was modified by polypropylene glycol diglycidyl ether (PPGDE) for the preparation of a surfactant (GLS), and firstly used for detergent builder. The effects of PPGDE content on the reaction and the properties of GLS were investigated. The structure of GLS was studied by Fourier transform infrared spectra (FTIR), ultraviolet spectrophotometer (UV), and gel permeation chromatography (GPC). The surface tension, critical micelle concentration (CMC), emulsifying ability, lime soap dispersing power (LSDP), and detergency were characterized. The results showed that GLS had higher surface activity and better emulsifying ability, LSDP, and detergency than that of LS. After decolorized by H₂O₂, the whiteness retention value of decolorized LS on white cloth reached 91.9%, while that of decolorized GLS increased up to 99.4%. These results suggested that the decolorized GLS may provide a new perspective for detergent builders.     

甲型副伤寒多糖-破伤风类毒素结合疫苗的制备及安全性和免疫原性

目的制备甲型副伤寒多糖-破伤风类毒素结合疫苗,并检测其安全性与免疫原性。方法副甲O-SP溶液加入CDAP活化,己二酰肼(ADH)衍化,在碳二亚胺(EDAC)作用下与破伤风类毒素(TT)偶联,反应物经柱层析纯化,制得多糖蛋白结合物,经质量检测后,进行安全性及免疫原性试验。结果所制备的结合物多糖蛋白比稳定在0.6~0.8之间,CL-4B检测Kd≤0.2时的回收率大于75%,高相对分子质量结合物含量不低于90%。免疫双扩散试验显示结合物与副甲家兔超免血清和TT抗血清均产生可见沉淀线。动物安全试验均合格。结合物免疫小鼠后,其血清副甲LPS抗体滴度显著增长,阳转率达到100%。结论用CDAP活化多糖制备的甲型副伤寒-破伤风类毒素结合疫苗质量稳定,安全可靠,且具有良好的免疫原性。     

Evaluation of the contents and ratios of five fractionated proteins to elucidate the protein composition in soybean seeds

Selecting suitable soybean cultivars is important for food processing and exploring their endowment with desirable physiological functions. We applied the fractionation method previously established to compare soy protein composition among cultivars to promote such a selection. More than 95% of the proteins in soybean cotyledons were extracted from 13 soybean cultivars using a high-concentration salt solution. The extracted proteins were fractionated into five fractions, namely oil body-associated protein (OBAP), polar lipid-associated protein (PLAP), globulins (11S and 7S), and whey by centrifugation after tuning the solubility behavior of the proteins with various solutions. Protein species in each fraction were analyzed by SDS-PAGE. Protein content in the total extract and five fractions was quantified to characterize the protein composition of soybean cultivars. The correlation between the protein content of each fraction and the total protein in cotyledon was investigated. A strong positive correlation was found only for the 11S fraction (r = 0.82), followed by a positive correlation in the 7S fraction (r = 0.65). Thus, we surmised that the increased protein content in soybean was due to increased globulin content. Furthermore, the calculation of the average ratio of protein content in each fraction indicated the globulin fraction (7S and 11S) to be 52%, the lipophilic protein fraction (OBAP and PLAP) to be 33%, and the whey fraction to be 13%. The preparation method employed in this study is a promising tool for efficiently comparing the protein composition of soybean cultivars to evaluate the potential use of cultivars for food production.     

TRAIL-Inspired Multivalent Dextran Conjugates Efficiently Induce Apoptosis upon DR5 Receptor Clustering

Triggering apoptosis of tumor cells has been in focus of cancer-inspired research since decades. As clustering of death receptor 5 (DR5), which is overexpressed on various cancer cells, leads to formation of the death-inducing signaling cascade (DISC), DR5 has recently become a promising target for tumor treatment. Herein, we demonstrate that covalent multimerization of a death receptor targeting peptide (DR5TP) on a dextran scaffold generates potent apoptosis-inducing conjugates (EC₅₀=2–20 nm ). A higher conformational flexibility compared to reported DR5TP multimerization approaches, introduced by the polysaccharide framework compensates the reported need for the defined ligand orientation that was considered as essential prerequisite for effective receptor clustering and apoptosis induction. Enzyme-catalyzed ligation of a hydrophilic dextran conjugate bearing multiple DR5-targeting sites to a human fragment crystallizable (Fc) receptor did not affect the potency (EC₅₀=2–7 nm ), providing an option for improved in vivo half-life and prospective conjugation to an antibody of interest in view of bispecific tumor targeting.     

聚乙烯己内酰胺的制备与表征

以乙烯己内酰胺单体(VCL)为原料,偶氮二异丁腈(AIBN)为引发剂,在水溶液中通过自由基聚合合成了聚乙烯己内酰胺. 考察了引发剂用量、溶剂用量、聚合反应时间和聚合反应温度对产物分子量和产率的影响,阐述了水溶液中自由基聚合的反应机理. 在VCL:AIBN:H2O=1:0.05:15(质量比),75℃下反应5 h的优化工艺条件下,产率能达到97%,并通过凝胶渗透色谱仪测定了聚合物的平均分子量. 以红外光谱和核磁共振对产品结构进行了表征,用分光光度计测定其临界溶解温度为32℃.     

葡聚糖的环氧化修饰与表征

以1，4-丁二醇二缩水甘油醚（BDE）为环氧化试剂，对葡聚糖（Dex）进行功能化修饰，探讨了投料比、pH值、反应时间等条件对环氧取代度的影响。通过核磁共振氢谱（1HNMR）表征产物的结构，采用多角激光光散射与尺寸排阻色谱联用分析系统（MALLS-SEC）考察产物的分子量及其分布。采用Axen方法测定产物的环氧取代度，并通过检测产物中环氧量随时间的变化情况考察了产物的稳定性。结果表明。环氧基团被成功地引入到葡聚糖的单元节上。并且通过改变反应条件可以对环氧取代度进行调控，得到稳定的环氧化葡聚糖产物；在反应温度为37℃、投料比n（Dex）：n（BDE）=1；30、pH=12．6、反应时间为12h的条件下，环氧取代度高达16％，且4℃的低温下环氧化葡聚糖在水中的稳定性良好。