共查询到20条相似文献,搜索用时 7 毫秒
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IDA型Cu~(2 )-螯合亲和膜色谱法对牛肝过氧化氢酶纯化的研究(英文) 总被引:3,自引:0,他引:3
首次采用以改性纤维素为基质、亚氨二乙酸(IDA)为取代配基的铜离子螯合膜色谱法对牛肝过氧化氢酶(BLC)的分离纯化进行了研究。缓冲液的pH值对BLC与螯合配基的结合影响显著。在选定的色谱条件下,BLC粗酶液经IDA型Cu2+-螯合膜色谱柱一步纯化,比活性平均提高4.7倍,回收率为67.7%。金属螯合膜色谱柱可用含0.2mol/L的咪唑或50mmol/LEDTA-1mol/LNaCl的缓冲液再生,反复使用,后者比前者对柱子的再生效果更好。 相似文献
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采用静电纺丝法制备了丙烯腈/丙烯酸共聚物(PANCAA)纳米纤维膜, 研究了纺丝液浓度对纤维形态的影响, 以扫描电子显微镜观察纤维形貌, 遴选得到最佳纺丝条件. 以1-乙基-3-(N,N-二甲基氨基丙基)碳二亚胺/N-羟基丁二酰亚胺(EDC/NHS)为偶联剂, 在纤维膜表面引入壳聚糖修饰层, 采用衰减全反射傅里叶变换红外光谱(ATR/FTTIR)、水接触角和称重法考察了修饰前后膜的变化. 通过戊二醛将过氧化氢酶固定到壳聚糖修饰的PANCAA纳米纤维膜上, 研究了壳聚糖及戊二醛浓度对固定化过氧化氢酶的影响, 结果表明, 在壳聚糖浓度为25 mg/mL及戊二醛质量分数为5%条件下, 壳聚糖修饰膜的固定化酶活性比空白膜提高了41.7%, 稳定性也得到了不同程度的提高. 相似文献
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IDA型Cu~(2+):-螯合亲和膜色谱法对牛肝过氧化氢酶纯化的研究(英文): 总被引:1,自引:1,他引:0
首次采用以改性纤维素为基质、亚氨二乙酸(IDA)为取代配基的铜离子螯合膜色谱法对牛肝过氧化氢酶(BLC)的分离纯化进行了研究。缓冲液的pH值对BLC与螯合配基的结合影响显著。在选定的色谱条件下,BLC粗酶液经IDA型Cu2+-螯合膜色谱柱一步纯化,比活性平均提高4.7倍,回收率为67.7%。金属螯合膜色谱柱可用含0.2mol/L的咪唑或50mmol/LEDTA-1mol/LNaCl的缓冲液再生,反复使用,后者比前者对柱子的再生效果更好。 相似文献
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在电位型尿素酶电极的组装过程中,要求尽量不改变尿素酶的构型和构象,使其在酶膜中保持其自然状态,从而可获得较高的酶活力.用pH玻璃电极作原电极,将尿素酶固定在其表面,常用的有戊二醛交联法[1]和各种聚合物膜法[2~4].本文利用60%季铵化的聚(4-乙... 相似文献
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乳胶微球固定化碱性磷酸酶的研究 总被引:3,自引:0,他引:3
本文系统地研究了生物素化碱性磷酸酶在微球载体上的固定化,确定了在胺化聚苯乙烯微球上固载的最适条件,并对所得固相酶的最适pH值,最适温度,米氏常数Km值等性能进行了测试,结果发现生物素化碱性磷酸酶固定于胺化微球后其最适pH值从9.5降低至9.3;酶的最适温度没有发生变化,但范围稍加宽;在50℃温度下处理90分钟,固相酶活化保持在40%,稳定性增强,固定化后酶的Km减小。 相似文献
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DNA与邻苯二胺-过氧化氢-过氧化物酶体系相互作用的光谱研究 总被引:2,自引:0,他引:2
用光谱方法研究了邻苯二胺-过氧化氢-过氧化物酶体系与DNA的作用,认为二者之间发生的是嵌插作用。分别用UV-Vis光谱和荧光光谱求得了形成常数,两种方法具有一致性。讨论了pH值对嵌插作用的影响。 相似文献
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报道了一种新的L-氨基酸氧化酶电极,这种酶电极系由氨气敏电极和以氨基化玻璃布为载体的酶膜所组成;研究了固定化条件对酶膜活性的影响以及底物浓度、温度和pH对电极响应特性的影响。该电极在6.0×10^-5~4.0×10^-3mol/L的底物浓度范围内呈良好的线性关系,检测下限为5.0×10^-5mol/L。在最宜条件下,酶电极具有良好的稳定性。 相似文献
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In this study, microcapsules were prepared by solvent evaporation technique using ethyl cellulose component as wall and essential oil as core material. The synthesis of microcapsules was carried out using different oil masses. The analysis of the microcapsules was carried out using field emission scanning electron microscope (FE-SEM) and UV spectrophotometric analysis using absorption spectrophotometer. The obtained results confirm the regular spherical shape and size of the synthesized microcapsules. The qualitative and quantitative spectrophotometric analysis of the microencapsulated immortelle oil was measured at the wavelength of 265 nm. The calibration diagram was used to calculate the unknown concentrations of the microencapsulated oil. The obtained results confirm the application of the presented method as relevant for the possible determination of microencapsulated oil on textile materials. 相似文献
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S. Gaspard M. Oujja E. Rebollar C. Abrusci F. Catalina M. Castillejo 《Spectrochimica Acta Part B: Atomic Spectroscopy》2007,62(12):1612-1617
The emulsion-coated transparent plastic-base film has been the main carrier for production and preservation of motion picture contents since the 19th century. The knowledge of the composition of black and white silver gelatine cinematographic films is of great importance for the characterization of the photographic process and for identifying the optimum conditions for conservation. A cinematographic film is a multi-component system that consists of a layer of photographic emulsion overcoating a polymeric support (plasticized cellulose triacetate) and a protective transparent cross-linked gelatine layer coating the emulsion. In the present work, Laser Induced Breakdown Spectroscopy (LIBS) is used to characterize the composition of the materials of cinematographic films. LIB spectra of film samples and of different individual film components, polymeric support and reference gelatines, were acquired in vacuum by excitation at 266 nm (Q-switched Nd:YAG laser, 6 ns, 10 Hz). In the cinematographic film, silver lines from the light-sensitive silver halide salts of the photographic emulsion are accompanied by iron, lead, chrome and phosphorus lines. Iron and lead are constituents of film developers, chrome is included in the composition of the hardening agents and phosphorus has its origin in the plasticizer used in the polymeric support. By applying successive pulses on the same spot of the film sample, it was possible to observe through stratigraphic analysis the different layers composition. Additionally, the results obtained reveal the analytical capacity of LIBS for the study and classification of the different gelatine types and qualities used for the protecting layer and the photographic emulsion. 相似文献
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Kiyoshi Hayakawa Hiromi Yamakita Kaoru Kawase 《Journal of polymer science. Part A, Polymer chemistry》1970,8(5):1227-1237
Graft copolymerization of maleimide onto ethyl cellulose and polyethylene films by using its sublimation vapor was carried out under γ- or ultraviolet irradiation. When polyethylene film was used as a backbone polymer the grafting reaction proceeded without a perceptible sorption of monomer, while a considerable amount of monomer was captured into ethyl cellulose film and grafting of the sorbed monomer was observed. The monomer seemed to be monomolecularly dispersed in this film. The presence of air retarded the reaction. The grafted films were characterized by strong infrared absorption bands due to polymaleimide branching. The fractions assigned to the graft copolymer were isolated from the grafted films by selective elution. The grafted branches were supposed to be very short, judging from the polymaleimide contents of those fractions. 相似文献
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Eriksson J Malmsten M Tiberg F Callisen TH Damhus T Johansen KS 《Journal of colloid and interface science》2005,284(1):99-106
Enzymatic degradation of model cellulose films prepared by a spin-coating technique was investigated by ellipsometry. The cellulose films were prior to degradation characterized by ellipsometry, contact angle measurements, ESCA (electron spectroscopy for chemical analysis) and AFM (atomic force microscopy). At enzyme addition to preformed cellulose films an initial adsorption was observed, which was followed by a total interfacial mass decrease due to enzymatic degradation of the cellulose films. The degradation rate was found to be constant during an extended time of hours, whereafter the degradation leveled off. In parallel to the decreased interfacial mass, the cellulose degradation resulted in a thinner and more dilute interfacial film. At long degradation times, however, there was an expansion of the cellulose film. The enzyme concentration affected the degradation rate significantly, with a faster degradation at a higher enzyme concentration. The effects of pH, temperature, ionic strength and stirring rate in the cuvette were also investigated. 相似文献
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固定化过氧化氢酶的制备及其抗氧化作用 总被引:1,自引:0,他引:1
以烟用醋酸纤维的生物化学改性为目标,研究了以壳聚糖为载体时,吸附交联固定化过氧化氢酶的条件,并考察了固定化酶的性质。结果表明,固定化的最佳条件为:加酶量(酶活2×104C IU/m l)6m l,3%壳聚糖20m l,乙二醛浓度6%(w/v),交联剂用量100m l,吸附时间0.5 h,交联时间2.5h,酶活收率可达42.9%。过氧化氢酶固定化后,动学参数Km值为61.7mmol/L;对活性氧具有较好清除作用。 相似文献
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《Journal of membrane science》1999,157(1):53-61
A mixed ester of ethyl cellulose (EC) has been prepared by reaction of trifluoroacetic anhydride with the residual hydroxy groups of ethyl cellulose. The mixed ester is soluble in tetrahydrofuran, dichloromethane, chloroform, benzene and pyridine. FTIR and NMR spectra show that hydroxy groups of ethyl cellulose were replaced by trifluoroacetoxy groups. The trifluoroacetyl ethyl cellulose (TFAEC) has higher selectivity for oxygen relative to nitrogen, in gas transport, than unmodified EC. Annealing at an elevated temperature further improves selectivity for oxygen, whilst subsequent ageing at ambient temperature partially reduces oxygen selectivity. The tensile strength of TFAEC is virtually the same as that of unmodified EC, but the elongation to break is 200% higher than for EC. 相似文献
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Direct electrochemical and electrocatalytic behavior of hemoglobin (Hb) immobilized on glass carbon electrode (GCE) containing gelatine (Gel) films was investigated. The characteristics of Hb/Gel film modified GC electrode were performed by using SEM microscopy, UV-vis spectroscopy and electrochemical methods. The immobilized Hb showed a couple of quasi-reversible redox peak with a formal potential of −0.38 V (versus SCE) in 0.1 M pH 7.0 PBS. The formal potential changed linearly from pH 4.03 to 8.41 with a slope value of −52.0 mV pH−1, which suggested that a proton transfer was accompanied with each electron transfer (ET) in the electrochemical reaction. The Hb/gelatine/GCE displayed a rapid amperometric response to the reduction of H2O2 and nitrite. 相似文献
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Reyes-Melo Martín Edgar Miranda-Valdez Isaac Yair Puente-Córdova Jesús Gabino Camarillo-Hernández Carlos Adrián López-Walle Beatriz 《Cellulose (London, England)》2021,28(14):9227-9240
Cellulose - This work deals with a green route to fabricate a biocompatible hybrid film composed of silver nanoparticles (AgNPs) and ethyl cellulose (EC). The hybrid film (AgNP/EC), with a... 相似文献
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Regenerated cellulose blend film with thermoplastic polyurethane (TPU) was successfully prepared by coagulating cellulose/TPU
solution with water in the presence of a thermoplastic polyurethane elastomer (TPU). Compared with pristine regenerated cellulose
film, the toughness and thermal stability of the blend film was significantly improved. For example, the elongation at break
was increased from 11% of pristine cellulose film to 51% of blend film with 20 wt. % TPU. The 50% weight loss temperature
of this blend film was increased by 33 °C compared to neat cellulose. The relaxation transition temperature of cellulose was
decreased with the addition of TPU through dynamic mechanical thermal analysis. The oxygen permeability was decreased from
2.3 × 10−10 cm3 cm/cm2 s Pa of pristine cellulose film to 0.08 × 10−10 cm3 cm/cm2 s Pa of the blend film with 20 wt.%. TPU The X-ray diffraction spectra showed that the crystallinity of cellulose decreased
with incorporation of TPU. The images of scanning electron microscope discovered that there was good compatibility between
cellulose and TPU. TPU was nano-dispersed in cellulose matrix. The blend film still maintained quite good transparency. 相似文献