DescriptionSpeI has a High Fidelity version SpeI-HF® (NEB #R3133).
High Fidelity (HF®) Restriction Enzymes have 100% activity in CutSmart™ Buffer; single-buffer simplicity means more straightforward and streamlined sample processing. HF enzymes also exhibit dramatically reduced star activity. HF enzymes are all Time-Saver™ qualified and can therefore cut substrate DNA in 5-15 minutes with the flexibility to digest overnight without degradation to DNA. Engineered with performance in mind, HF restriction enzymes are fully active under a broader range of conditions, minimizing off-target products, while offering flexibility in experimental design.
Product SourceAn E. coli strain that carries the SpeI gene from Sphaerotilus species (ATCC 13923).
The following reagents are supplied with this product:
|Store at (°C)||Concentration|
Properties and Usage
Unit DefinitionOne unit is defined as the amount of enzyme required to digest 1 µg pXba-XbaI DNA in 1 hour at 37°C in a total reaction volume of 50 µl.
1X CutSmart® Buffer
Incubate at 37°C
1X CutSmart® Buffer:
50 mM Potassium Acetate
20 mM Tris-acetate
10 mM Magnesium Acetate
100 μg/ml BSA
pH 7.9 @ 25°C
Activity in NEBuffersNEBuffer 1.1: 75%
NEBuffer 2.1: 100%
NEBuffer 3.1: 25%
CutSmart® Buffer: 100%
10 mM Tris-HCl
250 mM NaCl
1 mM DTT
0.1 mM EDTA
200 μg/ml BSA
0.15% Triton® X-100
pH 7.4 @ 25°C
Heat Inactivation80°C for 20 min
dam methylation: Not Sensitive
dcm methylation: Not Sensitive
CpG Methylation: Not Sensitive
Quality Control AssaysThe following Quality Control Tests are performed on each new lot and meet the specifications designated for the product. Individual lot data can be found on the Product Summary Sheet/Datacard or Manual which can be found in the Supporting Documents section of this page.
- Blue-White Screening (Terminal Integrity):
A sample of DNA vector linearized with a 10-fold excess of a restriction endonuclease, religated and transformed into an E. coli strain expressing the LacZ beta fragment gene results in less than 1% white colonies.
- Endonuclease Activity (Nicking):
The product is tested in a reaction containing a supercoiled DNA substrate. After incubation for 4 hours the percent converted to the nicked form is determined by agarose gel electrophoresis.
- Exonuclease Activity (Radioactivity Release):
The product is tested in a reaction containing a radiolabeled mixture of single and double-stranded DNA. After incubation for 4 hours the exonuclease activity is determined by the % release of radioactive nucleotides.
- Ligation and Recutting (Terminal Integrity):
After an over-digestion of DNA with a restriction endonuclease the percentage of the DNA fragments ligated with T4 DNA ligase and the percentage that can be recut are determined by agarose gel electrophoresis.
- Non-Specific DNase Activity (16 hour):
The product is tested for non-specific nuclease degradation in a reaction containing a DNA substrate. After incubation for 16 hours there is no detectable degradation of the DNA substrate as determined by agarose gel electrophoresis.
US 5,945,326, EP 0869174 (FR, GB, DE 69838012.6)
- Cleaves to leave a 5´ CTAG extension which can be efficiently ligated to DNA fragments generated by AvrII, NheI, or XbaI.
- Are there any common problems encountered when using SpeI?
- Can SpeI be used at alternative reaction temperatures?
- Is SpeI active at 25°C?
- Does SpeI produce commonly used compatible ends?
- What effect does BSA have on the performance of NEB’s restriction enzymes when included in the new buffers?
- Do I have to set-up digests with Time-Saver™ qualified enzymes for 5-15 minutes? Can I digest longer?
- How can I access the old NEBuffer Activity Chart?
- I tested your restriction enzyme on the substrate DNA recommended by NEB, and it appears to be active, however it does not digest my DNA. What could be the reason?