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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1、纳豆激酶是在纳豆发酵过程中由纳豆枯草杆菌(Bacillus subtilisl natto)产生的一种丝氨酸蛋白酶（单链多肽酶），分子量为27728道尔顿。
2、纳豆激酶在温度超过80℃时迅速变性失活，但反复冻融对其影响不大。
3、纳豆激酶在PH值从7升至12时，10min内稳定；PH值低于5时，迅速变性失活。胃酸环境中的PH值只有1.2到2之间，纳豆激酶根本无法通过。
4、纳豆激酶与粘性物质混合后，在PH值2-3的酸性环境中，还能保持不超过7.5%的活性。
5、纳豆激酶是大分子的单链多肽酶，可被肠道消化液（糜蛋白酶、胰蛋白酶、小肠液等）分解成氨基酸片段或分子量更小的肽链。
纳豆一词源于日本，是日本发酵食品，源自中国的咸豆豉，但并非中国豆豉，而是由黄豆通过纳豆菌（枯草杆菌）发酵制成豆制品，具有黏性，气味较臭，味道较甜，不仅保有黄豆的营养价值、富含维生素K2、提高蛋白质的消化吸收率，更重要的是发酵过程产生了多种生理活性物质，具有溶解体内纤维蛋白及其他调节生理机能的保健作用。
磷酸肌酸激酶（CPK），主要存在于骨骼肌和心肌，在脑组织中也存在，是参与体内的能量代谢的一种酶。在临床上主要用于诊断心肌梗塞。心肌梗塞患者发病后2－4小时，血液中此酶活动即开始升高。比血清中谷草转酸酶和乳酸脱氢酶的活力变化都出现得早。
临床意义：
（1）心肌梗塞后，CPK较谷草转氨酶和乳酸脱氢酶特异性高，但持续时间短，2－4天恢复正常。
（2）病毒性心肌炎，CPK也可升高，对诊断及预后有参考价值。
（3）进行性肌营养不良、多发性肌炎以及肌肉损伤时CPK也可升高。
（4）严重的心绞痛、心包炎、房颤、脑血管意外、脑膜炎以及心脏手术等，CPK可见升高。
根据PTK是否存在于细胞膜受体可将其分成受体型和非受体型。向左转|向右转
