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FastDigest Bsu15I

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

FastDigest buffer for 100% activity Optimal incubation at 37°C Cleavage blocked or impaired by CpG methylation Cleavage blocked or impaired by overlapping Dam methylation Thermal inactivation at 65°C in 15 min LO certified

The FastDigest Bsu15I restriction enzyme recognizes AT^CGAT sites and cuts best at 37°C in 5-15 minutes using universal FastDigest Buffer. This enzyme is an isoschizomer of ClaI having the same recognition and cleavage specificity (Isoschizomers: BanIII, Bsa29I, BseCI, BshVI, BspDI, BspXI, BsuTUI, ClaI).
Lambda DNA digested with ClaI (Bsu15I)

Lambda DNA digested with Bsu15I, 0.7% agarose, 15 cleavage sites

Thermo Scientific FastDigest enzymes are an advanced line of fast restriction enzymes that are all 100% active in the universal FastDigest and FastDigest Green reaction buffers.

The universal buffer allows rapid single-, double- or multiple DNA digestion within 5-15 minutes eliminating any need for buffer change or subsequent DNA clean-up steps. DNA modifying enzymes, such as Klenow Fragment, T4 DNA Ligase, alkaline phosphatases and T4 DNA Polymerase all have 100% activity in FastDigest Buffer. Therefore, enzymes for downstream applications can be directly added to the FastDigest reaction mix.

For additional convenience FastDigest Green Buffer includes a density reagent and two tracking dyes for direct loading of digestion reaction products on gels.

Short incubation times and optimal composition of the universal FastDigest Buffer eliminate star activity effects.


  • 100% activity of all FastDigest enzymes in the universal buffer
  • 100% buffer compatibility with downstream applications
  • Complete digestion in 5-15 minutes
  • Direct loading on gels
  • No star activity
  • 176 FastDigest enzymes available


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


The FastDigest Green Buffer offers the same high performance in DNA digestion and downstream applications as the colorless FastDigest Buffer. For applications that require product analysis by fluorescence excitation (e.g. concentration measurements in UV light) the colorless FastDigest Buffer is recommended.

For methylation sensitivity refer to product specifications.

Compatible EndsFastDigest XmiI, FastDigest SsiI, FastDigest Psp1406I, FastDigest Hin1I, FastDigest Bsp119I, FastDigest Hin6I, FastDigest Hpall, FastDigest MspI, FastDigest TaqI, AciI, AccI, AclI, BsaHI, Bsp119I, Hin1I, Hin6I, HinP1I, HpaII, MaeII, MspI, NarI, Psp1406I, SsiI, TaqI, XmiI.
Formulation1 μL of enzyme (1 FDU) cleaves 1 μg of lambda DNA in 5 minutes at 37°C in 1X FastDigest Buffer.
IsoschizomersSearch for commercial isoschizomers using REsearch.
Recommended Reaction Conditions

1X FastDigest buffer or 1X FastDigest Green buffer at 37°C.
1 µL of FastDigest ClaI (Bsu15I) is formulated to digest up to:

  • 1 µg of lambda DNA in 5 minutes
  • 1 µg of plasmid DNA in 5 minutes
  • 0.2 µg of PCR product in 5 minutes
  • 1 µg of genomic DNA in 5 minutes or 5 µg of genomic DNA in 30 minutes
Storage Condition-20 C

Reaction conditions

Reaction temperature Digestion time with 1 µL of FastDigest enzyme, min bp from end of DNA required for complete digestion Thermal inactivation Incubation time without star activity, hours
Lambda, 1 µg/20 µL Plasmid DNA, 1 µg/20 µL PCR product, ~0.2 µg/30 µL Genomic DNA, 1 µg/10 µL
37°C 5 5 5 5 2 65°C, 5 min 16

Methylation Effects

Methylation type Sequence Cleavage effect
Dam(GATC)5'...ATCGm6A TC...3'
3'...TAGC Tm6AG...5'

Number of recognition sites in DNA molecules

Lambda ΦX174 M13mp18/19 pBR322 puc18/19 pUC57
15 0 2 1 0 0
pTZ19R/U pTZ57R pBluescriptIIKS(±) pBluescriptIISK(±) pACYC177 pACYC184
0 0 1 1 1 1

New sites generated by ligation

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

Recognition Sequence Second Enzyme Enzymes recognizing newly generated recognition sequence
  • BmeT110I* (CY^CGAG)
  • Bsp119I (BstBI)/FastDigest Bsp119I (TT^CGAA)
  • TaqI/FastDigest TaqI (T^CGA)
  • XmiI (AccI)/FastDigest AccI (XmiI)* (GT^CGAC)
  • TaqI/FastDigest TaqI

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

Recognition Sequence Newly generated sequence after reaction Enzymes that cleave the newly generated sequence
  • Bsh1236I (BstUI)/FastDigest Bsh1236I
  • Hpy188III
  • Bsp68I (NruI)/FastDigest RruI