交联酶聚体技术研究进展

交联酶聚体（CLEAs）是一类新型的固定化酶技术,具有制备简单、酶活回收率高、操作和保存稳定性强等优点。近年来,CLEAs技术与材料学、印迹工程、介质工程、反应工程学等相结合取得了一系列新进展,包括载体固定化CLEAs、包埋CLEAs、印迹法CLEAs、多酶CLEAs、CLEAs膜浆反应器等,在手性分子拆分与合成。抗生素生产等领域取得了一些成果。本文对CLEAs酶活影响因素及CLEAs技术的最新研究进展进行了分析与总结,并展望了需进一步深入开展的内容,有助于生物工程、酶工程、化学工程和材料科学等领域相关研究工作的开展。     

交联酶聚集体与仿生硅化技术结合制备固定化脂肪酶

将交联酶聚集体(CLEAs)与仿生硅化技术相结合,制备了交联脂肪酶Candidasp.99-125杂化生物催化剂.以京尼平为交联剂,在最佳条件下制得的脂肪酶CLEAs的酶活达771U/g,回收率达75%;保护剂聚乙烯亚胺(PEI)与Candidasp.99-125脂肪酶共沉淀制备P/CLEAs,其酶活达897U/g,回收率约88%;利用PEI的诱导作用,在P/CLEAs表面形成氧化硅涂层,制得的脂肪酶CLEAs(Coated-CLEAs)显示出良好的稳定性,特别是其抗蛋白酶水解能力、有机溶剂耐受能力、重复使用性能等方面明显提高.     

交联血管紧张素转化酶聚集体的制备及性质

制备了交联血管紧张素转化酶聚集体（ACE-CLEAs）,比较了ACE-CLEAs及游离ACE的酶学性质,包括最适酶促反应温度、最适pH值、Km、vmax、温度稳定性及pH稳定性等。 以酶活力回收率为参考,确定了制备ACE-CLEAs的最佳条件为：饱和度为80%的(NH4)2SO4溶液作为沉淀剂,沉淀时间0.5 h,质量分数为0.02%的戊二醛作为交联剂,交联时间1 h。 通过比较酶学性质发现,ACE-CLEAs比游离ACE具有更好的温度稳定性及pH稳定性,且与游离ACE接近的Km值表明,ACE-CLEAs对底物的亲和力与游离酶几乎相当。     

FITC标记脂肪酶的稳定性和荧光光谱

脂肪酶;异硫氰基荧光素(FITC);荧光光谱;稳定性     

1，4-环己烷二甲醇改性生物可降解聚酯PBS的合成与性能表征

用熔融缩聚法合成了一系列聚（丁二酸丁二醇酯丁二酸-1,4-环己烷二甲醇酯）无规共聚物。通过。H—NMR、FT—IR、DSC、TGA、XRD、酶降解测试等方法表征了材料的结构与性能。结果表明：合成得到的共聚酯为预期产物;共聚酯的晶体结构发生了改变,并产生了共晶行为;随着1,4-环己烷二甲醇（CHDM）含量的增加,产物的熔点由113．7℃降至64．6℃,然后升至114．2℃,玻璃化转变温度由-33．8℃单调升高至5．4℃;CHDM的引入增强了共聚酯的热稳定性;酶降解测试得出产物P51、P31具有良好的生物降解性,且P51降解最快。     

Comparison of Methods for the Preconcentration of Cadmium (II) Using Amberlite XAD-16 Resin Modified with Anoxybacillus caldiproteolyticus and Geobacillus stearothermophilus as Novel Biosorbents

Abstract

The isolation, identification and characterization of bacteria obtained from soil of Ergani Makam Mountain were performed and the results revealed that the bacteria were thermophilic Anoxybacillus caldiproteolyticus. The characterized bacteria and purchased Geobacillus stearothermophilus were immobilized on Amberlite XAD-16 in order to prepare two biosorbents for preconcentration experiments for the determination of cadmium (II) ions. The produced biosorbents were enriched separately using mini-columns and the analyte was determined by flame atomic absorption spectrometry. The effects of solution parameters were investigated for the separation and preconcentration yields. The recovery efficiencies of Amberlite XAD-16 immobilized separately with A. caldiproteolyticus and G. stearothermophilus were determined to be 98.23?±?2.40 and 98.93?±?1.3 (n?=?5) for the optimum working conditions, respectively. Moreover, the Cd (II) ion was recovered with 10?mL of 1?mol L^?1 of HCl and 2?mL of 0.5?mol L^?1 HNO₃ solutions. The optimum working conditions were determined to be at pH 6.0 and a flow rate of 2?mL min^?1 for both biosorbents. The recovery efficiencies of matrix ions were characterized to investigate the feasibility of the developed preconcentration methods. The accuracy of the proposed methods were controlled by analyzing a SCP Science EnviroMAT Waste Water, Low (EU-L-2) certified reference material. The obtained results were comparable to the certified values. These methods were also applied to the analysis of water samples from Dicle River, Hazar Lake and Diyarbak?r tap water for Cd (II).     

固定化脂肪酶催化合成生物柴油

固定化脂肪酶催化合成生物柴油;转酯反应;固定化脂肪酶;菜籽油;甲醇;生物柴油     

Octanuclear Ni4Ln4 Coordination Aggregates from Schiff Base Anion Supports and Connecting of Two Ni2Ln2 Cubes: Syntheses,Structures, and Magnetic Properties

A family of 3d–4f aggregates have been reported through guiding the dual coordination modes of ligand anion (HL^?) and in situ generated ancillary bridge driven self‐assembly coordination responses toward two different types of metal ions. Reactions of lanthanide(III) nitrate (Ln=Gd, Tb, Dy, Ho and Yb), nickel(II) acetate and phenol‐based ditopic ligand anion of 2‐[{(2‐hydroxypropyl)imino}methyl]‐6‐methoxyphenol (H₂L) in MeCN‐MeOH (3 : 1) mixture and LiOH provided five new octanuclear Ni‐4f coordination aggregates from two Ni₂Ln₂ cubanes. Single‐crystal X‐ray diffraction analysis reveals that all the members of the family are isostructural, with the central core formed from the coupling of two distorted [Ni₂Ln₂O₄] heterometallic cubanes [Ni₂Ln₂(HL)₂(μ₃‐OH)₂(OH)(OAc)₄]⁺ (Ln=Gd ( 1 ), Tb ( 2 ), Dy ( 3 ), Ho ( 4 ) and Yb ( 5 )). Higher coordination demand of 4f ions induced the coupling of the two cubes by (OH)(OAc)₂ bridges. Variable temperature magnetic study reveals weak coupling between the Ni²⁺ and Ln³⁺ ions. For the Tb ( 2 ) and Dy ( 3 ) analogs, the compounds are SMMs without an applied dc field, whereas the Gd ( 1 ) analogue is not an SMM. The observation revealed thus that the anisotropy of the Ln³⁺ ions is central to display the SMM behavior within this structurally intriguing family of compounds.     

重组HEV衣壳蛋白截短体的表达及鉴定

戊型肝炎(HE)是由戊型肝炎病毒(HEV)感染引起的肠道病毒性传染病. HEV是一种无囊膜的单股正链RNA病毒, 其编码区由3个开放阅读框(ORF)组成, 属戊型肝炎病毒科. HEV衣壳蛋白由ORF2编码. 本研究根据编码HEV ORF2 aa382~aa674的核苷酸序列克隆了p293基因, 并将其克隆入原核表达载体pET28a, 利用大肠杆菌BL21(DE3)对HEV衣壳蛋白截短体(p293)进行了表达. SDS-PAGE和Western blot检测结果表明, 在优化的表达条件下(1 mmol/L IPTG, 250 r/min, 37℃, 5 h), 重组蛋白p293能够在大肠杆菌内有效表达, 目的蛋白约占总蛋白的66.15%. TEM检测结果显示, 原核表达的p293能够在体外形成约30~40 nm的病毒样颗粒. 免疫印迹和免疫荧光检测结果表明, p293与HEV标准阳性血清具有良好的反应原性和反应特异性. 实验结果表明, p293可应用于HEV宿主吸附和病毒装配研究, 为HEV的预防与诊断研究奠定了基础.     

柱状假丝酵母脂肪酶同工酶的一种高效液相色谱分离新方法

建立一种“疏水界面亲和色谱”分离柱状假丝酵母脂肪酶同工酶的高效液相色谱新方法。将商品化的CRL经离子交换色谱分离为两个同工酶组分 (CRLA和CRLB) ,在极低离子强度下 ,根据同工酶活性中心周围处于“开放”构象的疏水腔具亲疏水界面的特性 ,用疏水界面亲和色谱在NucleosilC4 (10 μ ,3 0 0 ,2 5 0× 4.60mm)柱上将CRLA和CRLB都分离为 4种同工酶组分。疏水界面亲和色谱非常适用于分离这种结构差异轻微的同工酶组分     

十六烷基三甲基溴化铵/山梨醇酐硬脂酸酯微乳液凝胶固定化脂肪酶的催化活性及立体选择性

制备了能在水溶液中长时间稳定存在的十六烷基三甲基溴化铵/山梨醇酐硬脂酸酯（CTAB/Span-60）微乳液凝胶（MBG）,确定了Span-60在乳化剂EM（正丁醇与Span-60的混合物）中的质量分数范围;分别以正己酸与正己醇的酯化反应、α-单硬脂酸甘油酯的水解反应、消旋布洛芬与正辛醇的不对称酯化反应为指示反应,研究了CTAB/Span-60 MBG固定化脂肪酶的催化活性及立体选择性。 结果表明,Span-60在EM中的质量分数小于57%时可形成机械强度较好的CTAB/Span-60 MBG;其固定化脂肪酶在有机溶剂中的酯化活性随EM中Span-60含量的增加先是逐渐增大,35%时最大,后又逐渐小幅度降低,在所考察的Span-60含量范围内均比在CTAB MBG中高;在水溶液中固定化脂肪酶能顺利催化α-单硬脂酸甘油酯的水解反应,24 h后反应转化率不再随反应时间的延长而增加,其水解活性在重复使用9次后仅降低13.68%,表明CTAB/Span-60 MBG固定化脂肪酶能够顺利进行分离并重复使用;此体系的脂肪酶也选择性地催化生成S-构型布洛芬辛酯,产物对映体过量值（eee）随反应的进行缓缓下降,但降幅不大,即其立体选择性要比在CTAB MBG中高。 因此,CTAB/Span-60 MBG作为脂肪酶固定化载体既可用于有机溶剂中又可用于水溶液中的生物合成与生物转化反应,扩大了微乳液凝胶固定化脂肪酶的应用范围。     

预聚-酶催化缩聚法合成超支化聚酯及其结构表征

以丙三醇、1,6-己二醇和己二酸为共聚单体,以固定化脂肪酶Novozym435为催化剂,尝试先进行共聚单体的预聚后在有机介质中进行酶催化直接缩聚反应合成脂肪族超支化聚酯的新途径,考察了反应介质和反应温度对酶催化缩聚反应的影响,并采用凝胶渗透色谱和核磁共振确定产物的分子量和结构.结果表明,将单体的预聚与酶催化缩聚反应相结...     

Biocatalysts Synthesized with Lipase from Pseudomonas cepacia on Glycol-Modified ZIF-8: Characterization and Utilization in the Synthesis of Green Biodiesel

This research presents results on the production of biodiesel from the transesterification of acylglycerides present in palm oil, using the biocatalysts ZIF-8-PCL and Gly@ZIF-8-PCL synthesized by immobilization of Pseudomonas Cepacia Lipase as catalytic materials and using pure ZIF-8 and Gly@ZIF-8 (modified ZIF-8) as supports. The Gly@ZIF-8 carbonaceous material was prepared by wet impregnation of ZIF-8 with ethylene glycol as the carbon source, and then thermally modified. The calcination conditions were 900 °C for two hours with a heating rate of 7 °C/min in an inert atmosphere. A textural characterization was performed, and results showed superficial changes of materials at the microporous and mesoporous levels for the Gly@ZIF-8 material. Both the starting materials and biocatalysts were characterized by infrared spectroscopy (FTIR) and Raman spectroscopy. During the transesterification, using the two biocatalysts (ZIF-8-PCL and Gly@ZIF-8-PCL), two supernatant liquids were generated which were characterized by infrared spectroscopy (FTIR), gas chromatography coupled to mass spectrometry (GC-MS), and nuclear magnetic resonance (NMR). The results show that the two routes of synthesis of supports from ZIF-8 will be configured as effective methods for the generation of effective biocatalysts for biodiesel production.     

Enzymatic ring-opening copolymerization of trimethylene carbonate and ethylene ethyl phosphate

A growing interest in biodegradable polymers and their biomedical and pharmaceutical applications has developed since the past decade. Ring-opening polymerization has been regarded as an efficient route for the synthesis of the biodegradable polymers, such as polyester, polycar- bonates and polyphosphates[1—6]. However, chemical methods for the ring-opening polymerization of biodegradable polymers need extremely pure monomers and anhydrous conditions as well as metallic catalysts, which must …     

Preparation and Characterization of Magnetic Metal–Organic Frameworks Functionalized by Ionic Liquid as Supports for Immobilization of Pancreatic Lipase

Enzymes are difficult to recycle, which limits their large-scale industrial applications. In this work, an ionic liquid-modified magnetic metal–organic framework composite, IL-Fe₃O₄@UiO-66-NH₂, was prepared and used as a support for enzyme immobilization. The properties of the support were characterized with X-ray powder diffraction (XRD), Fourier-transform infrared (FTIR) spectra, transmission electron microscopy (TEM), scanning electronic microscopy (SEM), and so on. The catalytic performance of the immobilized enzyme was also investigated in the hydrolysis reaction of glyceryl triacetate. Compared with soluble porcine pancreatic lipase (PPL), immobilized lipase (PPL-IL-Fe₃O₄@UiO-66-NH₂) had greater catalytic activity under reaction conditions. It also showed better thermal stability and anti-denaturant properties. The specific activity of PPL-IL-Fe₃O₄@UiO-66-NH₂ was 2.3 times higher than that of soluble PPL. After 10 repeated catalytic cycles, the residual activity of PPL-IL-Fe₃O₄@UiO-66-NH₂ reached 74.4%, which was higher than that of PPL-Fe₃O₄@UiO-66-NH₂ (62.3%). In addition, kinetic parameter tests revealed that PPL-IL-Fe₃O₄@UiO-66-NH₂ had a stronger affinity to the substrate and, thus, exhibited higher catalytic efficiency. The results demonstrated that Fe₃O₄@UiO-66-NH₂ modified by ionic liquids has great potential for immobilized enzymes.     

Synthesis and Characterization of Guanidinium Difluoroiodate, [C(NH2)3]+[IF2O2]– and its Evaluation as an Ingredient in Agent Defeat Weapons‡

Ammonium and guanidinium difluoroiodate(V), [NH₄]⁺[IF₂O₂]^– ( 1a ) and [C(NH₂)₃]⁺[IF₂O₂]^– ( 1b ), and diazidoglyoxime, [N₃C=N–OH]₂ ( 2 ) were synthesized and the molecular structures in the solid state of 1b and 2 were elucidated by single‐crystal X‐ray diffraction. 1b : P$\bar{1}$ , a = 6.6890(5), b = 10.2880(6), c = 10.30.92(8) Å, α = 105.447(6), β = 108.568(7), γ = 91.051(5)°, V = 644.08(8) Å³, ρ = 2.650 g · cm^–3; 2 : P2₁/n, a = 4.4211(3), b = 13.7797(9), c = 4.9750(3) Å, β = 98.735(6), V = 299.57(3) Å³, ρ = 1.886 g · cm^–3. The suitability of compounds 1a and 1b as active ingredients for agent defeat weapons (ADW) with biocidal activity has been shown in detonation tests using geobacillus stearothermophilus spores. In addition, a complete energetic characterization of the promising primary explosive 2 is given.     

笼型倍半硅氧烷形态分析及对杂化材料相容性和机械性能的影响

采用水解缩合方法制备了八乙烯基笼型倍半硅氧烷(OVPOSS), 并将其引入到聚甲基丙烯酸甲酯(PMMA)自凝树脂中, 得到有机-无机杂化材料. 通过傅里叶变换红外光谱(FTIR)、X射线衍射(XRD)、透射电子显微镜(TEM)、扫描电子显微镜(SEM)、差示扫描量热仪(DSC)、塑料球压痕硬度计、高温高速摩擦磨损测试仪和悬臂梁冲击实验等对其形貌和性能进行了研究. 结果表明, OVPOSS以晶体状态存在于PMMA树脂中. 通过DSC热性能曲线、FOX方程和Gordon-Talyor方程曲线发现, 当POSS含量较高时, PMMA-POSS杂化体系能够发生相分离, 对杂化材料的机械性能有一定的影响.     

Phytochemical Characterization and Bioactivity of Asparagus acutifolius: A Focus on Antioxidant,Cytotoxic, Lipase Inhibitory and Antimicrobial Activities

The phytochemical composition of leaves, stems, pericarps and rhizomes ethanolic extracts of Asparagus acutifolius were characterized by HPLC-DAD-MS. A. acutifolius samples contain at least eleven simple phenolics, one flavonon, two flavonols and six steroidal saponins. The stem extracts showed the highest total phenolic acid and flavonoid contents, where cafeic acid and rutin were the main compounds. No flavonoids were detected in the leaf, pericarp or rhizome while caffeic acid and ferulic acid were the predominant. Steroidal saponins were detected in the different plant parts of A. acutifolius, and the highest contents were found in the rhizome extracts. The stem extracts exhibited the highest antioxidant activity against 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) and the highest 2,2-azino-bis (3 ethylbenzothiazoline-6-sulphonic acid) (ABTS) scavenging activity was found in the pericarp extracts. The rhizome and leaf extracts showed a potent cytotoxic activity against HCT-116 and HepG2 cell lines. Moreover, the pericarp and rhizome extracts revealed a moderate lipase inhibitory activity. The leaf and rhizome extracts were screened for their antimicrobial activity against human pathogenic isolates. The leaf extract exhibited a powerful inhibitory activity against all the bacteria and fungi tested.     

带有PPE侧链的聚合物的合成及其发光性质的研究

有机共轭聚合物发光材料成为近年来多学科交叉研究的热点[1~3]。作为共轭聚合物之一,聚对苯乙炔(Poly(p-phenyleneethynylene))(PPE)具有较高的电子亲合势、电致发光效率、对微量水和氧气稳定等优点,近年来受到很大的关注[4~7]。PPE分子链间通过π-π堆积效应(π-πstacking)在