Lucigen/Exonuclease I, E. coli/X40520K/20,000 Units

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

1. Lehman,I.R.andNussbaum,A.L.(1964)J.Biol.Chem.239,2628.
2. Kushner,S.R.etal.(1971)Proc.Natl.Acad.Sci.USA68,824.
3. 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.