Human Topoisomerase II alpha and beta
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Human Topoisomerase II Alpha
Human topoisomerase II alpha is prepared by overexpressing in baculovirus-infected insect cells (Spodoptera frugiperda) and purifying it by methods developed in-house.
The enzyme is supplied in Dilution Buffer.
Store at -80°C.
It is recommended that larger pack sizes (500U and above) of the enzyme are aliquoted to avoid repeated freeze-thaw cycles.
See technical documents below for more detailed information and lot specific activities.
Technical Documents
Human Topoisomerase II Beta
Human topoisomerase II beta is prepared by overexpressing in baculovirus-infected insect cells (Spodoptera frugiperda) and purifying it by methods developed in-house.
The enzyme is supplied at a concentration of 2-10 U/μl in Dilution Buffer.
Store at -80°C. (Stable for 3 months undiluted).
It is recommended that the enzyme is aliquoted to avoid repeated freeze-thaw cycles.
Technical Documents
Human Topoisomerase II Decatenation Assay Kits
These contain human topo II and the catenated kDNA substrate in addition to the Assay and Dilution buffers for decatenation reactions. 1 U of human topo II 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. The kits are available with either the alpha or beta forms of the enzyme.
Technical Documents
Human Topoisomerase II Relaxation Assay Kits
These contain human topo II and the supercoiled DNA substrate in addition to the Assay and Dilution buffers for relaxation reactions. 1 U of human topo II will relax 0.5 µg supercoiled pBR322 DNA in 30 minutes at 37°C. The kits are available with either the alpha or beta forms of the enzyme.
Technical Documents
Human Topoisomerase II Assay Kits For Cell Extracts
These kits are designed for assaying cell extracts and partially purified fractions containing human topo II. They contain kDNA substrate, Assay buffer, Dilution buffer, decatenated and linear DNA markers and stop buffer / loading dye.
The kit components are based on the standard assay which contains 500 ng substrate DNA per assay.
Technical Documents
High / Medium-Throughput Assay Kit - Human Topoisomerase II
The kit is supplied with sufficient human topo II 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. The kits are available with either the alpha or beta forms of the enzyme.
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
Human Topoisomerase II alpha 453 subunit
Human topoisomerase II alpha amino acids 1-453. This contains the ATPase domain, the activity of which can be stimulated by DNA (see Campbell and Maxwell (2002), J.Biol.Chem. 320 p.171. The protein is expressed in E.coli.
Technical Documents
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炎性体（inflammasome）是细胞内的一类多蛋白复合物，在炎性反应中发挥着至关重要的作用。炎性体包括半胱天冬酶-1（caspase1）、PYCARD和NALP，有时也包括半胱天冬酶-5（caspase5，也被称作半胱天冬酶-11或ICH-3）。它是在骨髓细胞（myeloidcell）中产生的，也是先天性免疫系统的一个组分。炎性体的确切组成依赖于启动炎性体组装的激活物，如双链RNA和石棉会引发不同的炎性体组成。炎性体促进炎性细胞因子IL-1β和IL-18成熟。
在一项新的研究中，来自比利时法兰德斯生物技术中心/根特大学（VIB/UGent）的LieselotteVandeWalle博士、DanielJiménezFernández以及教授MoLamkanfi研究团队对半胱天冬酶-12（caspase12）的功能产生新的认识。基于此，他们打破了这个领域对半胱天冬酶-12的固执观念：半胱天冬酶-12是炎性体的负调节物。这些新的认识为研究人员挣脱现有的研究路线和鉴定它的真正生理学功能铺平道路。相关研究结果发表在2016年6月2日那期Nature期刊上，论文标题为“Doescaspase-12suppressinflammasomeactivation?”。
研究人员也指出这将需要进行大量的“重新研究（re-researching）”。之前所谓的半胱天冬酶-12在细胞死亡、应激反应、疟疾和败血症等中的作用---引用了9000多次---必需复核，这是因为这些作用经常是基于不正确的小鼠模型得出的。
VIB/UGent教授MoLamkanfi说，“我们发现在很多情形下，对半胱天冬酶-12的研究是基于对半胱天冬酶-11（caspase11）和半胱天冬酶-12都进行基因敲除的小鼠模型开展的。因此从研究结果中推断半胱天冬酶-12的作用是不可能的。我们如今引入新的选择性半胱天冬酶-12基因敲除小鼠，这应当能够让我们追踪半胱天冬酶-12的确切功能。”
利用这些新的小鼠，Lamkanfi团队证实在体外模拟的BMDM（bonemarrow-derivedmacrophage,骨髓衍生性巨噬细胞）和体内接种的小鼠中，半胱天冬酶-12缺乏都不能增加半胱天冬酶-1激活。剔除半胱天冬酶-12也不会增强炎性体途径释放出成熟的IL-1β和IL-18。他们的发现表明不论半胱天冬酶-11的表达状态如何，半胱天冬酶-12都不会作为半胱天冬酶-1激活的生理学上负显性调节物，因而也不会作为炎性体的生理学上负显性调节物。
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