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1.
研究了温度、酶浓度、反应时间、几种有机溶剂等因素对PstⅠ星号活力的影响,并在有利于星号活力的反应条件下测定了星号活力及原活力的Km分别为1.46×10^-7mol/L和1.02×10^-8mol/L,Vmax分别为2.86×10^-18mol/s和3.06×10^-15mol/s。  相似文献   

2.
甲基营养细菌No1甲胺脱氢酶的纯化和性质研究   总被引:3,自引:1,他引:3  
甲基营养细菌Nol甲胺脱氢酶是以色所酸-色氨酰醌为辅基的一种特殊氧化还原酶,粗酶液经纯化后,其比活力和收得率分别为5.1nmol.g^-1和28%。该酶的分子量为67000,等电点为8.3和8.5,组成它的大,小两上亚基的分子量分别为37000和15000。甲胺脱氢酶有较好的耐热性,它能催化包括一级甲胺和二胺在内的底物反应,与甲胺反应的Km值为26.6μmol.L^-1,最适pH为8.0。其酶催化  相似文献   

3.
拟除虫菊酯对昆虫ATPse的影响研究   总被引:1,自引:0,他引:1  
美洲大蠊中枢神经系统ATPase活力测定的最适应条件是:对于Na+K^+-ATPase,蛋白质含量5-10μg,pH值7.0,反应温度30℃,反应时间15min.Km和Vmax分别为5.38*10^-3mol/L和143.75nmol/min.mg^-1,Ca^2+-Mg^2+-ATPase基本相同。  相似文献   

4.
聚苯乙烯载体亲和层析纯化尿激酶   总被引:2,自引:0,他引:2  
聚苯乙烯经磺化后连接手臂6-氨基己酸,然后偶联配基对氨基苯甲脒,制成亲水性的亲和载体。载体的最适配基密度为每克湿载体32μmol,最适吸附条件为pH7.5、0.05mol/L磷酸缓冲液(含NaCl0.5mol/L)。在pH4.0、0.1mol/L醋酸缓冲溶液(含NaCl0.5mol/L)中,采用0~1mol/L NaSCN梯度洗脱,可将比活8.33μmol·S-1·mg-1的粗酶纯化50倍,收率大于53%。  相似文献   

5.
通过对磺胺嘧啶在多种底液中的极谱伏安行为研究,发现磺胺嘧定在BR缓冲溶液(pH4.2)和HAc-NaAc缓冲液(pH4.32)中产生良好的还原峰,峰电位分别为-0.76V和-0.79V(vs.SCE),在这两种底液中,峰电流或其导数峰高与磺胺嘧啶浓度在5×10^-7~4×10^-4mol/L和5×10^-6~3×10^-4mol/L范围内呈良好的线性关系,检测限为8×10^-7mol/L,可望用于  相似文献   

6.
磷酸盐及其结构类似物对文昌鱼酸性磷酸酶的影响   总被引:3,自引:2,他引:3  
研究了磷酸盐(HPO ̄(2-)_4)及其结构类似物钼酸盐(MoO ̄(2-)_4),钒酸盐(HvO ̄(2-)_4),钨酸盐(WO ̄(2-)_4)对文昌鱼酸性磷酸酶活力的影响及其抑制机理。实验结果表明:磷酸盐对文昌鱼酸性磷酸酶的抑制作用表现为竞争性抑制类型,而其结构类似物则是通过非竞争性抑制的方式抑制酶活力.抑制常数Ki分别为:磷酸盐:3.0×10 ̄(-4)mol/L,钼酸盐:5.5×10 ̄(-7)mol/L,钒酸盐:7.0×10 ̄(-7)mol/L,钨酸盐:3.8×10 ̄(-8)mol/L,用酸盐对酶活力呈时间抑制过程,表明该类似物可能通过氧化—还原这种新的抑制机理来抑制酶的活力。  相似文献   

7.
在PH7.00缓冲溶液中,当有0.0020%OP在在时,泰尔登在-1.95V产生一灵敏极谱波,利用此波可测定痕量泰尔登,检测下限为5.4×10^-9mol/L。用恒电位库仑法,计量库仑法和循环伏安法测得反应电子数为2,吸附量为1.17×10^-10mol/cm^2,扩散系数为4.3×10^-5cm^2/s。  相似文献   

8.
拟除虫菊酯对昆虫 ATPase 的影响研究   总被引:3,自引:0,他引:3  
美洲大蠊中枢神经系统ATPase活力测定的最适反应条件是:对于Na+-K+-ATPase,蛋白质含量5~10μg,pH值7.0,反应温度30℃,反应时间15min.Km和Vmax分别为5.38×10-3mol/L和143.75nmol/min·mg-1.Ca2+-Mg2+-ATPase基本相同,只是pH值为7.4,Km和Vmax分别为2.64×10-4mol/L和46.28nmol/min·mg-1.初步研究了氯氰菊酯及氰戊菊酯的不同异构体对ATPase的影响,结果显示均对ATPase有不同程度的抑制,与生测结果不完全一致.  相似文献   

9.
曲马多PVC膜选择性电极的研制   总被引:1,自引:0,他引:1  
周玲妹  徐献军 《河南科学》1994,12(2):119-122
介绍了一种曲马多PVC膜电极。该电极以曲马多——四苯硼缔合物为电活性物质,线性范围为4.0*10 ̄(-5)—4.0*10 ̄(-2)mol/L,检测下限为1.4*10 ̄(-5)mol/L,斜率为59.8mV/pc。电极在pH=3.0-7.0之间对曲马多的回收率为96.7%,电极被用于曲马多片剂和针剂中曲马多的含量测定,取得了较为满意的结果。  相似文献   

10.
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   

11.
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   

12.
There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.  相似文献   

13.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

14.
本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。  相似文献   

15.
Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with  相似文献   

16.
The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to  相似文献   

17.
18.
The explosive growth of the Internet and database applications has driven database to be more scalable and available, and able to support on-line scaling without interrupting service. To support more client's queries without downtime and degrading the response time, more nodes have to be scaled up while the database is running. This paper presents the overview of scalable and available database that satisfies the above characteristics. And we propose a novel on-line scaling method. Our method improves the existing on-line scaling method for fast response time and higher throughputs. Our proposed method reduces unnecessary network use, i.e. , we decrease the number of data copy by reusing the backup data. Also, our on-line scaling operation can be processed parallel by selecting adequate nodes as new node. Our performance study shows that our method results in significant reduction in data copy time.  相似文献   

19.
R-Tree is a good structure for spatial searching. But in this indexing structure,either the sequence of nodes in the same level or sequence of traveling these nodes when queries are made is random. Since the possibility that the object appears in different MBR which have the same parents node is different, if we make the subnode who has the most possibility be traveled first, the time cost will be decreased in most of the cases. In some case, the possibility of a point belong to a rectangle will shows direct proportion with the size of the rectangle. But this conclusion is based on an assumption that the objects are symmetrically distributing in the area and this assumption is not always coming into existence. Now we found a more direct parameter to scale the possibility and made a little change on the structure of R-tree, to increase the possibility of founding the satisfying answer in the front sub trees. We names this structure probability based arranged R-tree (PBAR-tree).  相似文献   

20.
The geographic information service is enabled by the advancements in general Web service technology and the focused efforts of the OGC in defining XML-based Web GIS service. Based on these models, this paper addresses the issue of services chaining,the process of combining or pipelining results from several interoperable GIS Web Services to create a customized solution. This paper presents a mediated chaining architecture in which a specific service takes responsibility for performing the process that describes a service chain. We designed the Spatial Information Process Language (SIPL) for dynamic modeling and describing the service chain, also a prototype of the Spatial Information Process Execution Engine (SIPEE) is implemented for executing processes written in SIPL. Discussion of measures to improve the functionality and performance of such system will be included.  相似文献   

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