
S. pneumoniae Topoisomerase IV
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S. pneumoniae Topoisomerase IV

Topo IV (from Streptococcus pneumoniae) is prepared by overexpressing the subunits in E. coli and purifying them by methods developed in-house.
The 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
S. pneumoniae Topoisomerase IV Relaxation Assay Kits

These contain S. pneumoniae topo IV 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
S. pneumoniae Topoisomerase IV Decatenation Assay Kits

These contain S. pneumoniae topo IV 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
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酶标仪按照功能的不同划分,可以分为(1)光吸收酶标仪(可见酶标仪,紫外/可见酶标仪)(2)荧光酶标仪(3)化学发光酶标仪。
分光光度计按照波长及应用领域的不同可以分为:(1)可见光分光光度计(2)紫外分光光度计(3)红外分光光度计(4)荧光分光光度计(5)原子吸收分光光度计。
分光光度计和酶标板存在一些不同之处,具体差别体现在以下三个方面:
(1)盛装待测溶液的容器:
分光光度计用的是比色皿,酶标仪使用的是塑料微孔板(酶标板)。比色皿只能起到盛装溶液的作用,每个比色皿一次只能盛装一种溶液。酶标板常用透明的聚乙烯材料制成,对抗原抗体有较强的吸附作用,因此用它作为固相载体,酶标板通常为48孔或96孔,每个微孔可以盛装不同的溶液。
(2)光路的方向:
分光光度计是水平光路,而酶标仪则是垂直光路。由于酶标板盛样本的塑料微孔板是多排多孔的,光线只能垂直穿过,因此酶标仪的光束都是垂直通过待测溶液和微孔板的,光束既可是从上到下,也可以是从下到上穿过比色液。垂直光的特点是标本吸光度受液体浓缩或稀释的影响小,不足之处是受被测样本液面是否水平、酶标板透光性、孔底是否平整等的影响较大。
(3)光路的长度:
由于光密度(OD值)与吸光系数, 待测组分的浓度以及光路长度成正比关系。
分光光度计采用的比色杯的宽度通常是1cm,所以光路长度固定为1cm。因此不同仪器,不同批次测量的数据具有同样的可比性。
而酶标仪采用的是垂直光路, 所以光路的长度应该是液体液面的高度。所以测得的值受到样品的体积的影响。
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
各位前辈,MTT法加样后第一天阳性组镜下看细胞全死了,样品组和阴性组镜下状态还可以,加DMSO后样品孔和阴性孔颜色粉红,阳性孔红紫到发黑,酶标仪检测,样品组和阴性组大概0.2-0.4,阳性组却有1.2-1.4,请问,这是怎么回事?细胞接板密度为4*104,100μL。向各位求助了,万分感谢!

