
E. coli Topoisomerase IV
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E. coli Topoisomerase IV

Topo IV (from Escherichia coli) is prepared by overexpressing the parC and parE subunits in E. coli and purifying them by methods adapted from Peng and Marians, 19991.
The parC and parE subunits are purified to >95% purity as judged by SDS-PAGE. The topo IV is supplied as a heterotetramer complex in Dilution buffer.
It is recommended that the enzyme is aliquoted to avoid repeated freeze-thaw cycles. Store at -80ºC.
All enzyme is supplied with 5X concentrated Assay Buffer and Dilution buffers which are also available separately.
See technical documents below for more detailed information and lot specific activities.
Technical Documents
E. coli Topoisomerase IV Relaxation Assay Kits

These contain the enzyme and the supercoiled DNA substrate in addition to the Assay and Dilution buffers for relaxation reactions. 1 U of topo IV will relax 0.5 µg supercoiled pBR322 DNA in 30 minutes at 37°C.
Technical Documents
E. coli Topoisomerase IV DecatenationAssay Kits

These contain the enzyme and the catenated kDNA substrate in addition to the Assay and Dilution buffers for decatenation reactions. 1 U of topo IV will decatenate 200 ng of kDNA when incubated in 1X Assay buffer in a total reaction volume of 30 µl at 37°C for 30 minutes.
Technical Documents
E. coli Topoisomerase IV Assay Kits for Cell Extracts

These kits are designed for assaying cell extracts and partially purified fractions containing over-expressed topo IV and contain supercoiled DNA substrate, Assay buffer, Dilution buffer, control relaxed DNA and stop buffer/loading dye.
Technical Documents
E. coli Topoisomerase IV Cleavage Assay Kits

These kits are designed specifically for cleavage reactions. They contain topo IV enzyme, supercoiled pBR322 DNA substrate and the Assay and Dilution buffers required for DNA cleavage reactions in addition to the enzyme and linearised pBR322 marker.
Cleavage specific enzyme available separately on request.
Technical Documents
E.coli Topoisomerase IV ATPase kits

These kits can be used to test the effects of potential ATPase inhibitors. For example, the coumarin drugs such as novobiocin inhibit the action of topoisomerase IV by competitively inhibiting the hydrolysis of ATP thus preventing supercoiling.
These assays are microtitre plate-based and thus large numbers of compounds can be screened in a relatively short period of time. They also continuous assays which can provide more information than an end point assay.
Technical Documents
High / Medium-Throughput Assay Kit - E. coli Topoisomerase IV

The kit is supplied with sufficient E. coli topo IV enzyme, plasmid DNA substrate, buffers and other assay components* for 100 assays. The enzyme is supplied at a concentration of 10 U/μl in Dilution Buffer. The kit is also supplied with sufficient wash buffers for one 96-well plate. These buffers are supplied as 20X concentrates and must be diluted with ultra pure water prior to use.
More information about this assay can be found on the "Services" page under "High/Medium Throughput Assay".
Kit issued with limited licence for individual use only.
Patent held by Inspiralis Ltd., Norwich, Norfolk, UK. (Patent No. GB0424953.8, US7838230)
Technical Documents
References
- Peng, H. and Marians, K.J. (1999) Overexpression and purification of bacterial topoisomerase IV, in DNA Topoisomerase Protocols Vol. I (Bjornsti, M-A., and Osheroff, N. eds.), Humana Press, Totowa, N.Jersey pp.163-169
- Maxwell, A., Burton, N.P. and O"Hagan, N. (2006) High-throughput assays for DNA gyrase and other topoisomerases. Nucleic Acid Res. 34 (15), e104
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请问BAC蛋白浓度测定波长是562,我们这边酶标仪的滤光片波长最接近的是595,这样也可以测吗
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首先,酶标仪是用于医疗卫生方面的,其次,酶标仪实际上就是一台变相的专用光电比色计或分光光度计,其基本工作原理与主要结构和光电比色计基本相同。比色计是被列入强制检定目录的,因此需要强制检定。
【酶标仪】即酶联免疫检测仪,是酶联免疫吸附试验的专用仪器,又称微孔板检测器。可简单地分为半自动和全自动2大类,但其工作原理基本上都是一致的,其核心都是一个比色计,即用比色法来进行分析。 测定一般要求测试液的最终体积在250μL以下,用一般光电比色计无法完成测试,因此对酶标仪中的光电比色计有特殊要求。
我需要做pcr,做之前用酶标仪测定同一管dna浓度时,数字相差很大,有100度的也有五六十的,这是正常现象么,因为要做正交实验,需要准确的浓度,这种状况,我应该怎么确定浓度呢?求助求助!!
我们的酶标仪是bio-tekSynergyHT的型号,在测96孔板细胞荧光的时候选择bottom,区域扫描5*5,但是数值出来以后每个孔只读了13个值而不是25个值,why?还有,激发光的光束是圆形的还是正方形的?区域扫描为什么不是整个孔的扫描,而只是中间一个很小的区域扫描?选择bottom和top模式的时候有什么区别?是激发光源一个从底部激发一个从顶部激发的吗?
求大神赐教!
从原理上说,酶标仪是通过对酶标板中液体的吸光值检测,获得一个OD值后进行定性或半定量的分析,达到检测的目的。其优点是仪器简单、价格低廉、方便操作;缺点是灵敏度低、检测范围窄、难以实现自动化等。
化学发光免疫分析仪是化学发光反应(酶促发光或直接发光)产生的光信号通过光电倍增管进行信号转换后等到相应的信号值,用RLU(相对光单位)表示,以达到定量或定性的检测目的。优缺点几乎就是酶标仪的反面。
ELISA试剂盒一般现在用的较多的是可拆的酶标板,假设你之前买了一些可拆酶标板,那么今后彻底可以只买些酶标板条就可以了。不一样的厂家做出来的酶标板整体看上去是差不多的,但是有些小的细节方面会做的不一样,比如结构等,这主要是因为要合作不一样酶标仪运用,因此,当你在选择收购酶标板时还要考虑一下你的酶标仪是什么姿态。不过一般都是适配的,只需单个的会有所不一样。
因为ELISA试剂盒酶标板的质料一般为聚苯乙烯(PS),而聚苯乙烯的化学稳定性较差,可以被多种有机溶剂(如:芳烃、卤代烃等)溶解,会被强酸强碱腐蚀,不抗油脂,在遭到紫外光照耀后易变色,所以在运用过程中一定要注意这些。而这时石英酶标板便是最佳选择了,即可重复运用,又可以耐酸碱及有机溶剂的腐蚀。
测器和微处理器控制系统等组成.
光源灯发出的光线经过滤光片或单色器后,成为一束单色光.该单色光束经过酶标板中的待测标本,被标本吸收掉一部分后,到达光电检测器.光电检测器将投照到
上面的光信号的强弱转变成电信号的大小.此电信号经前置放大、对数放大、模数转换等处理后,送人微处理器进行数据处理和计算,最后通过显示器和打印机输出
测试结果.

