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1.
嗜盐菌碱性淀粉酶特性研究   总被引:4,自引:0,他引:4  
碱性嗜盐菌HalobacteriumspH-371产生的淀粉酶经超滤、硫酸铵沉淀和DEAE-纤维素纯化后,SDS-PAGE凝胶电泳为一条带,分子量为27000,等电点3.7,最适反应pH9.0,最适反应温度65℃.NaCl是维持酶活性的必需因子,酶解产物为麦芽糖、麦芽三糖、麦芽四糖和麦芽五糖  相似文献   

2.
黑曲霉单宁酶的纯化及部分性质研究   总被引:7,自引:0,他引:7  
黑曲霉在五倍子单宁的诱导下产生单宁酶。通过(NH4)2SO4分形沉淀,DEAE-Sepharose离子交换层析,Sephadex G-150凝胶过滤,从黑曲霉的发酵液和菌丝中纯化得到凝胶电泳均一的单宁酶。酶作用的最适温度为30℃,最适pH值为5.5,在温度10-30℃和pH4-6之间保持稳定,金属离子对单宁酶没有的激活作用,Fe^2+和Mn^2+则对酶有抑制作用。  相似文献   

3.
棒曲霉UA—2木聚糖酶的蔗渣固态发酵   总被引:3,自引:0,他引:3  
棒曲霉(Aspergilusclavatus)UA-2固态发酵蔗渣产木聚酶的培养基为每克蔗渣加营养液5ml,初始pH8.5.营养液的适宜组成为每升含:NH4NO310g、K2HPO46g、MgSO4·7H2O0.75g、CaCl20.75g、FeSO4·7H2O11.25mg、MnSO4·H2O3.75mg、ZnSO43.0mg、CoCl24.5mg.在上述培养基中接入其湿重10%(W/W)的新鲜的UA-2种子曲,28℃培养108h,其木聚糖酶,滤纸降解酶和羧甲基纤维素酶的活力分别为2695.6、28.5和42.7u/g蔗渣.酶反应的最适pH5.0,最适温度50℃;在pH4.0~11.0内酶活性十分稳定.50℃保温1h,酶活剩余55%,8℃下放置23d,活力几乎不变.磷酸盐,半胱氨酸对酶有激活作用,EDTA和对氯汞本甲酸对酶有抑制作用  相似文献   

4.
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   

5.
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   

6.
诺卡氏菌株82(Nocardiasp.82)可产生一种β一淀粉酶,经50%硫酸铵沉淀、DEAE一纤维素离子交换层析,将其纯化21倍。该酶在60℃,pH7.0条件下酶活最高;100℃处理30min仍具有40%的最初酶活力。  相似文献   

7.
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   

8.
染料脱色酶特性研究   总被引:4,自引:1,他引:3  
从脱色优势菌ND1 提取脱色酶,对酶特性进行研究.结果表明酶的最适作用条件为pH 7,37℃,无氧环境,反应需NADH 的参与;纯化结果表明经DEAE柱层析及Sephadex G-100 凝胶层析后脱色速率分别提高10 倍和50倍,Sephadex G-100 凝胶层析中2~4 管蛋白具有偶氮和蒽醌染料脱色酶活性,6~12 管具有蒽醌染料脱色酶活性.  相似文献   

9.
以赤子爱胜蚓为材料制得蚯蚓纤溶酶,测得该酶最适温度和最适pH值分别为55℃和9。其分子量分布范围为1.8×104~4.2×104道尔顿。在最适温度和最适pH条件下,该酶动力学参数km和V(max)以分别为0.5345g/L和18.0728unit/min,PSMF对该酶活性抑制率为70%。  相似文献   

10.
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   

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.
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   

15.
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   

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.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  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   

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