HumanTopoIProductBackground
TopoGENnowoffersahighpurityandcatalyticallyactiveTop1Enzymeoverexpressedinthebaculovirussystemandpurifiedtosinglebandhomogeneity. ThesepreparationsarecheaperthannativetopoImadefromhumantissueandofferexcellentpurityandhighspecificactivity. Inaddition,the100kDaformof recombinanttopoIisstableandislesspronetoproteolysis,relativetothenativeproteinfromhumancells.
QualityControlTests:
- 1
- AtestfornucleasecontaxaminationwascarriedoutbyassayingfortheformationoflinearKDNAandlinearplasmidDNA. Incubationsof1µgofcatenatedKDNAorsupercoiledpUC19DNA(4hrs.at37°Cinthepresenceof10mMMgCl2)wereperformed. LinearDNAorbreakdownproductswerenotgeneratedundertheseconditions.
- 2
- AcheckforcrosscontaminationwithtopoIIwasnegative. TherewasnodecatenationofkDNAintopoIIreactionconditions.
- 3
- ThefinalfractionoftopoisomeraseIisacolumnpoolandisinthefollowingbuffer:20mMNaH2PO4(pH7.4),300mMNaCl,50ug/mlBSA,50%glycerol,50mMImidazole*. ThefinalfractionwasanalyzedbySDS-PAGEandshowntocontainasingle,predominantbandof100kDa.
*Actualconcentrationcanrangefrom25mM-100mM,accordingtohowstockenzymewasdilutedinstoragebuffer.
ActivityAssays:
Relaxationassayswerecarriedoutinafinalvolumeof25µlinrecombinanttopoIreactionbuffer(10Xreactionbuffer,suppliedwiththisproductis:100mMTris-Cl,pH7.9,1.5MNaCl,1%BSA,1mMSpermidine,50%glycerol). SupercoiledplasmidDNAwasincludedat0.25µg/reaction. Reactionsterminatedwith5µl(per20µlreactionvolume)ofstopbuffer(5%sarkosyl,0.0025%bromophenolblue,25%glycerol).Reactionproductswereanalyzedona1%nativeagarosegel. Undertheseconditions,relaxationactivityiseasilydetectable(typicallywesee10-40unitsofactivityperul). Atypicaltitrationisshownbelow:
- ReviewsandCitations:
- YoshizakiA,YanabaK,OgawaA,AsanoY,KadonoT,SatoS:ImmunizationWithDNATopoisomeraseIandFreund'sCompleteAdjuvantInducesSkinandLungFibrosisandAutoimmunityviaInterleukin-6Signaling. ArthritisandRheumatism2011,63:3575-3585. doi:10.1002/art.30539.
- ZhangL,SullivanP,SuyamaJ,et.al:Epidermalgrowthfactor-inducedheparanasenucleolarlocalizationaugmentsDNAtopoisomeraseIactivityinbrainmetastaticbreastcancer. MolecularCancerResearch2010,8:278-290.doi:10.1158/1541-7786.MCR-09-0375
IncludedMaterials:
10Xassaybufferanddilutionbufferisincluded. ThesemaybepurchasedseparatelyasTGS10XTopoIAssayBuffer(TG4095).