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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非病理原因导致转氨酶高得情况
1、健康人如果剧烈运动后检查转氨酶就会发现转氨酶升高。
2、如果过于劳累，会导致转氨酶升高。
3、检查前如果吃过油腻的食物或酗酒都会导致转氨酶升高。
4、怀孕的人，也会导致内分泌失调，使得转氨酶升高;
5、营养不足 饮食结构不合理如低蛋白饮食，尤其是当食物中缺乏胱氨酸、维生素E时，亦可使ALT升高。
6、日常服用的药物所产生的副作用也会导致转氨酶升高，比如红霉素、安眠药、解热镇痛药、避孕药膏还有半夏、槟榔、青黛等中药。
病理性原因导致转氨酶高得情况
1、病毒性肝炎这是引起转氨酶高常见的疾病，其他类型的肝炎也可导致转氨酶高。
2、多种药物和化学制剂都能引起转氨酶高，但停药后可恢复正常。
3、肝硬化与肝癌肝硬化活动时，一般都会出现转氨酶高。
4、胆道疾病如胆囊炎、胆石症急性发作时，除伴有发热、腹痛、恶心、呕吐、黄疸等情况外，还可引起血胆红素及转氨酶高。转氨酶是从胆管排出的，如果有胆管、胆囊及胰腺疾患，胆管梗阻，也可使转氨酶升高。病床上常见的有胆囊炎、胆管蛔虫、肝胆管结石、胆囊及胆管肿瘤、壶腹部周围癌症、先天性胆管扩张症、急慢性胰腺炎、胰头痛以及出血坏死性胰腺炎。
5、心脏疾病急性心肌梗塞、心肌炎、心力衰竭时，可引起转氨酶高。
6、其他某些感染性疾病，：除肝脏外，体内其他脏器组织如心、肾、肺、脑、睾丸、肌肉也都含有此酶。因此，当心肌炎、肾盂肾炎、大叶性肺炎、肺结核、多发性肌炎、甲状腺功能亢进症、急性败血症、肠伤寒、流脑、疟疾、钩端螺旋体病、流行性感冒、麻疹、血吸虫病、挤压综合征等患者中，亦可见血中转氨酶升高。
7、是否服用过对肝脏有损害的药物，如果有，一定要注意药物性肝炎的可能；
8、女性还要注意有无自身免疫性肝炎的可能，检查自身免疫抗体（抗核抗体、抗平滑肌抗体等）是否为阳性；
9、既往是否有胆囊炎、心脏病、肾炎等疾病，这些病也可以引起转氨酶升高；
综上所述，引起转氨酶升高的原因很多，必须认真检查，明确病因，针对病因加以治疗。
转氨酶水平在0—40之间是正常的。如果超出正常范围，医生会建议再查一次，排除由于实验室设备故障和操作错误等因素造成误差的可能。如果转氨酶水平还高，多半是由病毒性肝炎或其他肝病所致。但要确定是不是病毒性肝炎，还需要做其他检查，结合病史、症状、体征等全面分析。展开
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Exercisedampensaromataseinhibitor–relatedjointpain
http://www.internalmedicinenews.com/specialty-focus/oncology-hematology/single-article-page/exercise-dampens-aromatase-inhibitor-related-joint-pain/33383ff19a0cd42399a7cf8590708ebf.html
SANANTONIO–Adoptingastandardexerciseprogramresultedinaclinicallymeaningful30%reductioninaromataseinhibitor-associatedjointpaininbreastcancerpatientswhoparticipatedinayear-longrandomizedtrial.
TheexerciseprescriptionutilizedintheHOPE(HormonesandPhysicalExercise)trialwaswhat’srecommendedinnationalguidelinesbothforcancersurvivorsandhealthyadults:150minutesperweekofatleastmoderate-intensityaerobicactivity,suchasbriskwalking,alongwithtwostrength-trainingsessionsperweek,MelindaL.Irwin,Ph.D.,explainedattheSanAntonioBreastCancerSymposium.
TheHOPEstudiesenrolled121postmenopausalwomenwhohadstage1-3,hormonereceptor–positivebreastcancersandwerephysicallyinactiveandoverweightyetphysicallyabletoexercise.Atenrollment,theywereexperiencingmoderatearomataseinhibitor(AI)–associatedjointpain,definedasascoreof5-7onthe0-10BriefPainInventory(BPI),afterabout18monthsonthemedication.Roughlytwo-thirdsofparticipantshadnohistoryofjointpainpriortostartingAItherapy;therestreportedtheAIexacerbatedtheirpreexistingjointpain.Subjectswererandomizedtotheexerciseprogramortousualcare,whichincludedwritteninformationabouttheimportanceofexercise.
Theprimarystudyendpointwasthe12-monthchangeinBPIworstpainscore,whichdroppedbyanaverageof30%amongtheexercisegroup.Thistranslatedtoanimprovementinpainlevelfrommoderateatbaselinetomildatfollow-up.Inaddition,BPIscoresratingpainseverityandpaininterferenceimprovedbyabout20%.Incontrast,patientsintheusualcarecontrolgroupexperiencedaslightincreaseinBPIscoresinallthreedomainsovertime,addedDr.Irwin,co-leaderofthecancerpreventionandcontrolresearchprogramatYaleUniversityCancerCenter,NewHaven,Conn.
TheHOPEresultsreceivedanenthusiasticaudiencereception.Physicianswereparticularlyimpressedwiththe70%exerciseadherencerateoverthecourseofayear.Theyaskedhowtheycankeeptheirpreviouslysedentarypatients’commitmenttoregularexercisefromwaningafteraninitialburstofenthusiasm,assooftenhappens.
Dr.Irwinrepliedthatadherencetolifestylechangeisalwaysachallenge.Socialsupportisquitehelpful.TheexercisegroupinHOPEreceivedapaidgymmembershipandmetinsmallgroupswithapersonaltrainertwiceweekly.
"Thewomenreallybondedwitheachother.Andtherearenowagrowingnumberoffreeprogramsthroughoutthecountry,whichgivecancersurvivorsastartonanexerciseprogramwithafreegymmembershipforseveralmonths.Forexample,theLivestrongFoundationhaspartneredwiththeYMCAtoofferfreeexerciseprogramsforcancersurvivorsatlocalYs,"shesaid.
TheHOPEtrialwasfundedbytheNationalCancerInstitute.Dr.Irwinreportedhavingnofinancialconflictsofinterest.
Thisdegreeofimprovementinjointpainisgreaterthanreportedinstudiesofglucosamine,acupuncture,orvitaminDsupplementation,shenoted.
Theimprovementinpainscoresintheexercisegroupwasgreaterat12monthsthanat3or6,suggestingthatayear-longexerciseprogramisprobablynecessarytoseesustainedreductioninjointpain.
At12monthsoffollow-up,womenintheexercisegroupaveraged159minutesofphysicalactivityperweek,110minutesmorethancontrols.Compliancewiththesupervisedexerciseprogramwasnotablygood,withwomenattendinganaverageof70%ofthetwice-weeklysmall-groupstrength-trainingsessions.
InadditiontotheimprovementinAI-relatedarthralgias,theexercisegroupexperiencedancillarybenefits:amean6.5%improvementinpeakoxygenconsumption,orVO2max,comparedwithbaseline,alongwitha3%reductioninbodyweight.
HOPEwasthefirstrandomizedtrialtoexaminetheeffectsofexerciseonAIsideeffectsinbreastcancerpatients.TheimpetusforthestudywastherecognitionthatarthralgiasarethemostcommonreasonforpooradherencetoanddiscontinuationofAItherapy.Upto20%ofbreastcancerpatientsdiscontinuetheirAIwithinthefirstyear.Andbothearlydiscontinuationandpooradherencehavebeenshowntobepredictiveofincreasedmortalityrisk.
入院10天，伴有肩部肌肉刺痛，已有好转，但今天的肝功能常规检查，转氨酶突然从140多升到310多，入院一直有互肝措施，静脉输液。无不良饮食习惯。有慢性浅表性胃炎病史。问，转氨酶突然升高的原因？各项肝炎检查无问题，ct x 光无问题
现在在做酶抑制剂，通过检测酶催化反应中吸光度的变化来判断酶活，从而评定酶抑制剂的好坏。
简单的来说，抑制剂浓度增加，酶活变小，吸光度应该持续变小
然而实验测试中发现，酶抑制剂浓度增加时（由10e-9到10e-5），酶活先增加再急剧减小，求问原因？
怀疑过是我自己测吸光度不准的原因，但是平行试验，发现每次都是10e-8和10e-7这两个浓度的酶活有问题，它们甚至比不加抑制剂下的酶活更高。
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