首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 46 毫秒
1.
通过DEAE-CelluloseDE-52和DEAE-SePhadexA-50离子交换层析等提纯步骤,对解脂假丝酵母胞外脂肪酶进行了纯化,得到了层析纯样品,比活提高27.4倍,得率11%.该酶反应最适温度为40℃;最适PH为7.5;等电点约在PH4.5~5.0之间;8℃以下存放,酶活力损失较少,30℃以上存放,酶活力有明显损失.金属离子Sr2+,Ba2+,Zn2+和Mg2+对该酶的激活作用为Sr2+>Ba2+>Zn2+>Mg2+.Cu2+和Na+对酶活性有抑制作用.NaN3对保持酶活性有重要作用.  相似文献   

2.
木霉4131菌株纤维素酶的分离纯化和部分性质研究   总被引:6,自引:0,他引:6  
绿色木霉(Trichoderma Viride)突变菌株4131^[1]产生的纤维素酶经过sephadexG-75和DEAE-sephadex-A-25两种层析分离,分离得到具有内切α-葡聚糖酶(CMCase)活性的纯组分,提纯后酶的比活力提高到原来的26.2倍;回收率为32.8%,分子量为56900,等电点为4.0,最适反应温度为55℃,最适pH为4.5,金属离子K^+,Na^+,Mg^2+对其  相似文献   

3.
背角无齿蚌酸性磷酸酶的分离、纯化及部分性质研究   总被引:6,自引:0,他引:6  
从背角无齿蚌外套膜中,经盐析,DEAE-Sephadex A-50离子交换柱层析及Sephadex,G-150凝胶过滤等步骤,分离提纯到一种酸性磷酸酶,提纯倍数88.25酶液比活力为24.7U/mg,通过动力学方法测得其最适pH值为4.8,最适温度为50℃,同样以对硝基苯磷酸二钠作底物测得其Km值为0.73mmol/L ,Zn^2+对酶有激活作用,而F^-,Pb^2+和Ba^2+则对酶有一定的抑制  相似文献   

4.
生淀粉糖化菌NL—3的发酵条件   总被引:5,自引:0,他引:5  
以黑曲霉(Aspergilusniger)523原生质体为对象,经激光、紫外线和亚硝基胍复合诱变,选育出高产生淀粉糖化酶突变株黑曲霉NL3,其生淀粉酶活力为156U/ml.产酶最适培养条件为:起始pH45,30℃,96h产酶量达最高.K+,Mg2+对NL3产生淀粉糖化酶有促进作用;Zn2+对产酶有抑制作用.酶的最适作用条件为:以玉米淀粉为底物的最适温度50℃,最适pH45;以甘薯淀粉、马铃薯淀粉为底物时最适温度60℃,最适pH40~45.酶在60℃保温15min,玉米淀粉为底物时酶剩余活力为80%;甘薯淀粉、马铃薯淀粉为底物时酶剩余活力为98%.  相似文献   

5.
嗜碱细菌NTT33碱性β—甘露聚糖酶的纯化与性质研究   总被引:6,自引:0,他引:6  
根据了嗜碱芽孢杆菌NTT33产生的碱性β-甘露聚糖酶经纯化后,在PAGE电泳上呈现一条蛋白带,分子量为3.89×10^7,等电点为3.0 ̄4.0,酶反应最适pH为9.0 ̄10.0,最适作用温度为80℃,稳定pH为6.0 ̄9.0,稳定温度为60℃以下,金属离子Cu^2+,Mg^2+,Al^3+,Co^2+对该酶有一定的激活作用,而Ag^+,Hg^2+,Mn^2+对该酶有明显抑制作用,经薄层层析鉴定,  相似文献   

6.
黑曲霉(Aspergillusniger728)的粗酶液,经硫酸铵沉淀,SephadexG-25柱凝胶过滤脱盐,DEAE-Toyopearl离子交换柱层析和SephacryS-100凝胶层析纯化,经PAGE鉴定为一条带SDS凝胶电泳测定分子量为70000.金属离子Fe3+对该酶有一定的抑制作用,该酶的等电点为3.7,最适pH为4,最适温度为60℃.E2801%为15.72,Km值为0.112×10-3m.  相似文献   

7.
木聚糖降解菌的筛选和木聚糖酶性质的研究   总被引:15,自引:0,他引:15  
筛选两株生长快、产木聚糖酶活力高的菌种;黑曲霉(Aspergillusniger,AN01)、链霉菌(Streptomycessp.Str7B),酶活力分别达128mg/L·min和176mg/L·min;酶反应最适温度分别为60℃与50℃;最适pH值为5.0和6.0,并分别在pH2.2~5.0,5.8~6.4酶活性稳定;在60℃条件下保温1.5h,酶活力分别剩余20.5%,88.5%,其中AN01株原酶液在90℃保温10min,活力仍剩余14.5%.Cu2+对酶活表现出极强抑制,Fe2+,Mg2+,Ca2+等离子则有促进作用;用纸层析法探讨了不同培养时间各种产物产生的情况.  相似文献   

8.
福寿螺β-葡萄糖苷酶的分离纯化及性质的初步研究   总被引:12,自引:5,他引:7  
以福寿螺内脏为材料,经本实验室开发的工业生产法制备粗酶粉,进一步采用葡聚糖凝胶(SephadexG-200)和DEAE-SephadexA-50柱层析纯化,获得经SDS-聚丙烯酰胺凝胶电泳鉴定为单一纯的β-葡萄糖苷酶制剂.测定该酶的最适反应温度为43℃,最适反应pH为5.1;在pH5.1,45℃下,该酶催化水杨素水解的Km值为3.40mmol/L,活化能为50.63kJ/mol.研究几种效应物对酶活力的影响,结果表明:Mn2+、Co2+对酶有激活作用,而Cu2+、Hg2+、Pb2+、SDS及脲对酶有不同程度的抑制作用,其中Cu2+和Hg2+对该酶的抑制作用最强,其抑制机理均表现为非竞争性抑制  相似文献   

9.
黑曲霉A3(AspergilusnigerA3)为高产木聚糖酶菌株。该菌所产生的木聚糖粗酶经硫酸铵、乙醇沉淀,SephadexG-100和DEAE-SephadexA-50分离纯化后,获得3个组分,分别称为X1、X2、X3。它们的最适反应温度和pH依次为40、50、50℃和35、45、50。  相似文献   

10.
激光复合诱变黑曲霉原生质体选育热稳定菊粉酶高产菌   总被引:1,自引:0,他引:1  
以菊粉酶产生菌黑曲霉AS-4原生质体为对象,经激光和亚硝基胍复合诱变,从大量突变株中最终选育出高产热稳定的菊粉酶产生菌AL-154.在以菊芋提取液为碳源、玉米浆加0.3%酵母膏为氮源的基本培养基中,菊粉酶活力达146.3u/mL,比出发株提高近3倍.其产酶最适营养条件为:起始pH4.5~5.0,28~30℃,36h时产酶量达最高.酶作用最适条件为pH5.0,60℃;该酶遗传性能稳定,热稳定性强,60℃保温处理2h,其酶活性不变,65℃保温30min,仍保留98%的初始酶活  相似文献   

11.
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.  相似文献   

12.
The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.  相似文献   

13.
王慧 《科技信息》2008,(10):240-240
Wuthering Heights, Emily Bronte's only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.  相似文献   

14.
何延凌 《科技信息》2008,(4):258-258
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.  相似文献   

15.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

16.
Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.  相似文献   

17.
以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.  相似文献   

18.
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。  相似文献   

19.
Quality traits in wheat (Triticum aestirum L.) were studied by quantitative trait locus (QTL) analysis in a recombinant inbred line (RIL) population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross (ChSh). Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.  相似文献   

20.
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.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号