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5'...TC T A G A...3'
3'...A G A T CT...5'

Available as a FastDigest enzyme for rapid DNA digestion

Available as FastDigest Enzyme Works best in Tango Yellow Buffer Functions optimally at 37°C Sensitive to Dam methylation Inactivate by incubation at 65°C for 20 minutes Available at a high concentration (50 U/µL) Cleaves agarose-embedded DNA LO Certified

The XbaI restriction enzyme recognizes T^CTAGA sites and cuts best at 37°C in Tango buffer
Lambda DNA digested with XbaI

Lambda DNA (dam-) digested with XbaI, 0.7% agarose, 1 cleavage sites

Thermo Scientific conventional restriction endonucleases are a large collection of high quality restriction enzymes, optimized to work in one of the buffers of the Five Buffer System. In addition, the universal Tango buffer is provided for convenience in double digestions. All of the enzymes exhibit 100% activity in the recommended buffer and reaction conditions. To ensure consistent performance, Thermo Scientific restriction enzyme reaction buffers contain premixed BSA, which enhances the stability of many enzymes and binds contaminants that may be present in DNA preparations.


  • Superior quality – stringent quality control and industry leading manufacturing process
  • Convenient color-coded Five Buffer System
  • Includes universal Tango buffer for double-digestions
  • BSA premixed in reaction buffers
  • Wide selection of restriction endonuclease specificities


  • Molecular cloning
  • Restriction site mapping
  • Genotyping
  • Southern Blot
  • Restriction fragment length polymorphism (RFLP)
  • SNP


For methylation sensitivity refer to product specifications.

Compatible EndsBcuI, Eco130I, NheI, XmaJI.
Conditions for 100% Activity
  • 1X Buffer Tango: 33 mM Tris-acetate (pH 7.9 at 37°C), 10 mM Mg-acetate, 66 mM K-acetate, and 0.1 mg/mL BSA
  • Incubate at 37°C
Digestion of Agarose-embedded DNAMinimum 5 units of the enzyme are required for complete digestion of 1 µg of agarose-embedded lambda DNA in 16 hours.
Double DigestionPerform double digestion using DoubleDigest.
IsoschizomersSearch for commercial isoschizomers using REsearch.
  • Assayed using Lambda DNA (dam-) (#SD0021).
  • XbaI is blocked by overlapping dam methylation. To avoid dam methylation, use a dam-, dcm- strain such as GM2163.
Storage BufferXbaI is supplied in 10 mM Tris-HCl (pH 7.4 at 25°C), 100 mM KCl, 7 mM 2-mercaptoethanol, 1 mM EDTA, 0.2 mg/mL BSA, and 50% (v/v) glycerol.
Storage Condition-20 C

Reaction conditions

Recommended buffer for 100% activity Optimal temperature Enzyme activity in Thermo Scientific buffers, % Tango buffer for double digestion
B (blue)
G (green)
O (orange)
R (red)
1X / 2X
Tango 37°C 50-100 50-100 20-50 0-20 100 50-100 1X or 2X

Methylation Effects

  • Dam: may overlap – blocked.
  • Dcm: never overlaps – no effect.
  • CpG: never overlaps – no effect.
  • EcoKI: never overlaps – no effect.
  • EcoBI: never overlaps – no effect.
Methylation type Sequence Cleavage effect
Dam(GATC) 5'...TCTAGm6A TC...3'
3'...AGATC Tm6AG...5'

Cleavage efficiency close to the termini of PCR fragments

bp from the recognition site to fragment end
1 2 3 4 5
20-50 50-100

Number of recognition sites in DNA molecules

Lambda ΦX174 M13mp18/19 pBR322 puc18/19 pUC57
1 0 1 0 1 1
pTZ19R/U pTZ57R pBluescriptIIKS(-/+) pBluescriptIISK(-/+) pACYC177 pACYC184
1 1 1 1 0 1

New sites generated by ligation

Newly generated recognition sites resulting from ligation of protruding compatible DNA ends

Recognition SequenceSecond EnzymeEnzymes recognizing newly generated recognition sequence
  • BcuI (SpeI)/FastDigest SpeI (BcuI) (A^CTAGT)
  • Eco130I (StyI)/FastDigest StyI (Eco130I)* (C^CTAGG)
  • NheI/FastDigest NheI (G^CTAGC)
  • XmaJI (AvrII)/FastDigest AvrII (XmaJI) (C^CTAGG)
  • FspBI (BfaI)/FastDigest BfaI (FspBI)

Newly generated recognition sites resulting from fill-in of 5'-overhang and self-ligation

Recognition SequenceNewly generated sequence after reactionEnzymes that cleave the newly generated sequence
  • AluI/FastDigest AluI
  • CviJI
  • [FspBI (BfaI)/FastDigest BfaI (FspBI)]
  • SetI