壳聚糖固定化果胶酶的制备及其酶学性质研究

以1％壳聚糖与5％戊二醛交联8h制得交联壳聚糖载体,1g载体固定10mg的果胶酶,载体先与酶液缓慢振荡混合30min后,在固定化体系（pH3．4,4℃）中固定反应12h,该条件下制得的固定化酶强度大韧性好。酶活力回收率高达56．31％;固定化酶的最适温度50℃,最适pH3．4,Km^app值为5．42mg·mL^-1,连续使用7次后,酶活力还保留70．45％以上,具有较好的操作稳定性。     

温敏性大孔聚(丙烯酰胺-co-N-异丙基丙烯酰胺)微球在固定化果胶酶中的应用

采用在反相悬浮聚合中加入致孔剂的方法制备温敏性大孔PAM-co-PNIPAM微球,并以该微球为载体固定化果胶酶,探讨了温度、pH值、时间、加酶量、戊二醛浓度、交联温度、交联时间对果胶酶固定化效果的影响,同时对固定化果胶酶的酶学特性进行研究.结果表明:该微球具有很好的比表面积和温度敏感性;当固定化果胶酶的载酶量高达322.6mg/g时,载体本身仍能保持较好的稳定性.固定化果胶酶在pH为3.0～4.5,温度为50～60℃的范围内仍能保持较高的酶催化活性.在存储30d后固定化酶的活性仍能保持为原来的80%左右,而且具有较高的操作稳定性,在连续使用20次后,仍有68%以上的活性.     

聚苯乙烯阴离子交换树脂吸附交联法固定α—淀粉酶

用聚苯乙烯阴离子交换树脂作载体,戊二醛为交联剂,采用吸附交联法固定α＿淀粉酶,研究了固定化条件和固定化酶的性能．结果表明,最佳固定化条件为：酶浓度１２ｇ／Ｌ,吸附温度６～９℃,吸附时间２０ｈ,戊二醛浓度４％,交联时间８ｈ,交联温度６～９℃,ｐＨ７．２．固定化酶的热稳定性、贮存稳定性、ｐＨ稳定性均比自由酶提高．最适作用温度５０℃,最适作用ｐＨ７．２,且适宜作用温度及ｐＨ均较自由酶宽,批式及连续操作实验显示出较好的操作稳定性．吸附交联联用法所得固定化α＿淀粉酶稳定性较好,克服了吸附法所得固定化酶稳定性差的缺点．     

大孔树脂吸附固定化脂肪酶机理研究

目的 探讨大孔树脂吸附固定化脂肪酶机理.方法 选取4种不同树脂(XAD1180,XAD7HP,A568,XAD18),通过氮气低温吸附法对栽酶树脂的孔径分布情况进行分析,对吸附-交联法制备固定化脂肪酶的工艺条件进行考察.结果 XAD1180为最适的固定化载体,其最佳固定化条件为:给酶量1 400～1 600μg/mL,戊二醛浓度为0.05%(体积分数),缓冲液pH7.5,吸附温度30℃,吸附时间10 h.结论 XAD1180树脂为南极假丝酵母脂肪酶理想的吸附固定化栽体.吸附同时用戊二醛交联,可以起一定加固脂肪酶的作用.     

壳聚糖固定化木瓜蛋白酶的制备及性质

以壳聚糖为载体，戊二醛为交联剂制备固定化木瓜蛋白酶，研究了固定化时间、温度、pH值、给酶量和戊二醛浓度对固定化木瓜蛋白酶活力的影响，结果表明：木瓜蛋白酶最佳经条件是给酶量为每克载体10mg，戊二醛浓度0.5%，pH7.5，室温下（25℃）反应10h。所制备的固定化木瓜蛋白酶的最适pH8.0，最适温度70℃，与溶液酶相比，固定化酶的热稳定性显著提高。     

壳聚糖固定化蚯蚓纤溶酶及其性质

以壳聚糖为载体,戊二醛为交联荆,用吸附交联法固定蚯蚓纤溶酶,对蚯蚓纤溶酶的固定化条件及固定化酶的各种性质进行了研究,确定了酶固定的最适条件:1 g用pH为6.5的磷酸盐缓冲液浸泡的壳聚糖载体与5 mL体积分数为1%戊二醛在25℃交联8 h,充分洗去戊二醛之后,加入蚯蚓纤溶酶13 U,4℃吸附6 h,充分洗去未交联的游离酶,酶活力回收最高大约为63%,固定化酶的比活为0.082 U/mg.固定化酶,游离酶的最适温度均为50℃,游离酶的最适pH值为8.5,而固定化酶的最适pH值为8.0,固定化酶的热稳定性,pH稳定性均比游离酶有所提高,游离酶、固定化酶都能水解纤维蛋白原和纤维蛋白,固定化酶不再水解BSA.     

修饰性载体固定化漆酶

采用壳聚糖铜固定化和交联酶聚集体的方法固定化漆酶.探索了固定化前后漆酶的最适温度、pH,热稳定性和金属离子对其活性的影响,交联漆酶聚集体制备的条件.结果为:游离漆酶的最适温度是20℃,最适pH是4.6;壳聚糖铜固定化漆酶的最适温度是25℃,最适pH是4.0;交联漆酶聚集体的最适温度是15℃,最适pH是3.6.固定化后漆酶的热稳定性提高,不同金属离子影响固定化漆酶的活性,其中K+的激活作用尤为明显.制备交联漆酶聚集体最适戊二醛浓度为1%,最适交联时间是2 h.     

壳聚糖固定化风味蛋白酶的制备及其酶学特性

研究了球形交联壳聚糖固定化风味蛋白酶的制备工艺及其酶学特性.以壳聚糖为载体、戊二醛为交联剂,采用共价交联法制备固定化风味蛋白酶的较适条件为ω(壳聚糖)=2.5％、ω(NaOH) =3％、ω(戊二醛)=0.5％,交联时间6h,载体中∞(酶)=40 mg/g,于35℃、pH值5.5条件下固定化反应10h.固定化后,风味蛋白酶较适反应温度从50℃提高至70℃,较适pH值从7.0提高至8.0,且可在更宽温度与pH值范围内保持较高的酶活力.固定化风味蛋白酶具有良好的储存稳定性和操作稳定性,可反复多次使用,适宜于在工业生产中推广应用.     

以卵清蛋白为载体的固定化木瓜蛋白酶的制备及其性质

以变性的卵清蛋白为载体, 用戊二醛为交联剂固定木瓜蛋白酶. 通过正交实验考察了固定化pH值、 交联剂戊二醛浓度、 交联时间和酶用量对固定化木瓜蛋白酶活力的影响,确定了最适固定化条件： 5%戊二醛, pH 6.0, 交联时间20 h, 每克载体含酶量12 mg. 对比研究了游离木瓜蛋白酶和固定化木瓜蛋白酶的性质, 所得到的固定化木瓜蛋白酶最适温度90 ℃, 最适pH 9.0, 米氏常数53.6　mg/mＬ, 其热稳定性及耐热性均较游离酶显著提高.     

壳聚糖固定化木瓜蛋白酶的制备及性质

以壳聚糖为载体 ,戊二醛为交联剂制备固定化木瓜蛋白酶 .研究了固定化时间、温度、pH值、给酶量和戊二醛浓度对固定化木瓜蛋白酶活力的影响 ,结果表明 :木瓜蛋白酶最佳固定化条件是给酶量为每克载体 10mg ,戊二醛浓度0 .5 % ,pH7.5 ,室温下 (2 5℃ )反应 10h .所制备的固定化木瓜蛋白酶的最适pH8.0 ,最适温度 70℃ ,与溶液酶相比 ,固定化酶的热稳定性显著提高     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with     

Journal of Donghua University ( English Edition) Contents of Volume 31

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