DigestssDNA,butnotdsDNA,ina3´to5´direction
Specific:ProcessivelydigestssDNAina3´to5´directionwithoutharmingdsDNA-short3´overhangsinDNAarenotdigested- FlexIBLe:Activeunderawidevarietyofbufferconditionsandcanbeaddeddirectlyintomostreactionmixes
- HeatInactivated:Destroytheenzymeactivitybyincubatingat80°Cfor15minutes
ExonucleaseIdigestsssDNAina3´to5´direction,1-3butdoesnotdigestdsDNA.Althoughitrequiresthepresenceofmagnesiumandafree3´-hydroxylterminusforactivity,itisactiveunderawidevarietyofbufferconditionsandcanbeaddeddirectlyintomostreactionmixes.ExonucleaseIcanbeheat-inactivatedbyincubationat80°Cfor15minutes.
Applications
- RemovalofresidualssDNA,includingoligos,fromreactionmixes.
- RemovalofssDNAfromnucleicacidmixtures.
UnitDefinition:OneunitofExonucleaseIcatalyzesthereleaseof10nmolofacid-solublenucleotidesfromheat-denaturedcalfthymusDNAin30minutesat37°Cunderstandardassayconditions.
StorageBuffer:50%glycerolcontaining50mMTris-HCl(pH7.5),0.1MNaCl,0.1mMEDTA,1mMDTT,and0.1%Triton®X-100.
QualityControl:ExonucleaseIistestedindegradationofssDNAandisfreeofdetectableRNase,endonuclease,anddouble-strandedexonucleaseactivities.
References
- Lehman,I.R.andNussbaum,A.L.(1964)J.Biol.Chem.239,2628.
- Kushner,S.R.etal.(1971)Proc.Natl.Acad.Sci.USA68,824.
- Kushner,S.R.etal.(1972)Proc.Natl.Acad.Sci.USA69,1366.
 | Figure1.SpecificityofExonucleaseIforssDNA.200ngofEcoRI-linearizedpUC19dsDNAand1µgofa100-merssDNAoligoweremixedin1XTABufferandincubatedat37°Cfor20minintheabsenceorpresenceof10unitsofExonuclease I.Asseenonthis1%agarosegel,ExonucleaseIcompletelydigestedthelinearssDNAoligo,butleftthelinearizedplasmiddsDNAintact.Lane1,sizeMarkers;Lane2,minusExoI;Lane3,plusExoI. | |
