BstEII has an HF version  supplied with CutSmart Buffer.
cloned at neb recombinant timesaver 5min incubation temp heat inactivation no
Catalog #SizeConcentrationPriceQtyAdd to Cart
R0162S2,000 units10,000 units/ml$60.00Add to Cart
R0162L10,000 units10,000 units/ml$242.00Add to Cart
R0162M10,000 units50,000 units/ml$242.00Add to Cart
Restriction Endonucleases: B,
Time-Saver™ Qualified Restriction Enzymes
Restriction Enzyme Digestion


BstEII has a High Fidelity version BstEII-HF® (NEB #R3162).

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 Source

An E. coli strain that carries the BstEII gene from Bacillus stearothermophilus ET (N. Welker).

Reagents Supplied

The following reagents are supplied with this product:

Store at (°C)Concentration
NEBuffer 3.1-2010X

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 60°C in a total reaction volume of 50 µl.

Reaction Conditions

1X NEBuffer 3.1
Incubate at 60°C

1X NEBuffer 3.1:
100 mM NaCl
50 mM Tris-HCl
10 mM MgCl2
100 μg/ml BSA
pH 7.9 @ 25°C

Activity in NEBuffers

NEBuffer 1.1: 10%
NEBuffer 2.1: 75%
NEBuffer 3.1: 100%
CutSmart® Buffer: 75%

Diluent Compatibility

Storage Temperature


Storage Conditions

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

Heat Inactivation


Methylation Sensitivity

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

Activity at Temperature

@37°C: 50%


  1. Of the over 3,000 known restriction endonucleases, BstEII is one of the few that produces extensions of more than 4 bases.
  2. May exhibit Star Activity in NEBuffer 2.1 and CutSmart Buffer.
  3. Based on the stability of the enzyme in the reaction, incubations longer than 1 hr will not result in improved digestion, unless additional enzyme is added. Please refer to Restriction endonuclease survival in a reaction for more information regarding this topic.
  4. Star activity may result from a glycerol concentration of >5%


  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. Why is my Restriction Enzyme not cutting DNA?
  5. Why do I see a DNA smear on an agarose gel after a restriction digest?
  6. Why do I see additional DNA bands on my gel after a restriction digest?
  7. How many nucleotides do I have to add adjacent to the RE recognition site in order to get efficient cutting?

Tech Tips

BstEII will exhibit star activity in a low salt buffer.
You will not get additional cutting after incubation at 60C for 1-2hr.


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

Selection Charts

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.
  • 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.

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.