• My NEB
  • Print
  • PDF
  • CspCI


    Product Source

    An E.coli strain that carries the CspCI gene from Citrobacter species 2144 (C. Nkenfou).

    Reagents Supplied

    The following reagents are supplied with this product:

    Store at (°C)Concentration
    CutSmart® Buffer-2010X
    S-adenosylmethionine (SAM)-2032 mM

    Properties and Usage

    Unit Definition

    One unit is defined as the amount of enzyme required to digest 1 µg of λ DNA in 1 hour at 37°C in a total reaction volume of 50 µl.

    Reaction Conditions

    1X CutSmart® Buffer
    Supplement with 20 μM S-adenosylmethionine (SAM)
    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

    Usage Concentration

    5,000 units/ml

    Activity in NEBuffers

    NEBuffer 1.1: 10%
    NEBuffer 2.1: 100%
    NEBuffer 3.1: 10%
    CutSmart® Buffer: 100%

    Diluent Compatibility

    Storage Temperature


    Storage Conditions

    10 mM Tris-HCl
    100 mM NaCl
    1 mM DTT
    0.1 mM EDTA
    200 μg/ml BSA
    50% Glycerol
    pH 7.4 @ 25°C

    Heat Inactivation

    65°C for 20 min

    Methylation Sensitivity

    dam methylation: Not Sensitive
    dcm methylation: Not Sensitive
    CpG Methylation: Not Sensitive


    1. CspCI cleaves on both sides of its recognition sequence excising a ~35 base-pair fragment with 2-base 3´-overhangs.
    2. The exact positions of cleavage can vary ± one base depending on the sequence of the DNA flanking the recognition site and the digestion conditions
    3. S-adenosylmethionine or SAM is supplied as a 32 mM solution in 0.005 M sulfuric acid and 10% ethanol. Under these conditions SAM is stable for up to 9 months when stored at -20°C. 


    1. What effect does BSA have on the performance of NEB’s restriction enzymes when included in the new buffers?
    2. Do I have to set-up digests with Time-Saver™ qualified enzymes for 5-15 minutes? Can I digest longer?
    3. How can I access the old NEBuffer Activity Chart?
    4. 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?
    5. Why is my Restriction Enzyme not cutting DNA?
    6. Why do I see a DNA smear on an agarose gel after a restriction digest?
    7. Why do I see additional DNA bands on my gel after a restriction digest?
    8. How many nucleotides do I have to add adjacent to the RE recognition site in order to get efficient cutting?


    1. Optimizing Restriction Endonuclease Reactions
    2. Double Digest Protocol with Standard Restriction Enzymes
    3. Time-Saver Protocol for Restriction Enzyme Digests

    Selection Charts

    Feature Articles

    Usage Guidelines & Tips

    Troubleshooting Guides

    Interactive Tools

    Quality Control

    Quality Control Assays

    The 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. Further information regarding NEB product quality can be found here.
    • 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.
    • 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.

    Certificate of Analysis

    The Certificate of Analysis (COA) is a signed document that includes the storage temperature, expiration date and quality control's for an individual lot. The following file naming structure is used to name these document files: [Product Number]_[Size]_[Version]_[Lot Number]


    The Specification sheet is a document that includes the storage temperature, shelf life and the specifications designated for the product. The following file naming structure is used to name these document files: [Product Number]_[Size]_[Version]

    Safety Data Sheet

    The following is a list of Safety Data Sheet (SDS) that apply to this product to help you use it safely.