Product Class: Nuclease

DNase I (RNase-free)

cloned at neb recombinant unique buffer incubation temp heat inactivation
Catalog #SizeConcentration
M0303S1,000 units2,000 units/ml
M0303L5,000 units2,000 units/ml



Isolated from a recombinant source
Supplied with 10X Reaction Buffer DNase I, (RNase-free) is an endonuclease that nonspecifically cleaves DNA to release di-, tri- and oligonucleotide products with 5´-phosphorylated and 3´-hydroxylated ends (1,2). DNase I acts on single- and double-stranded DNA, chromatin and RNA:DNA hybrids.

Product Source

An E. Coli strain that carries an MBP fusion clone of Bovine Pancreatic DNase I.

Reagents Supplied

The following reagents are supplied with this product:

Store at (°C)Concentration
DNase I Reaction Buffer-2010X

Advantages and Features


  • Degradation of DNA template in transcription reactions
  • Removal of contaminating genomic DNA from RNA samples
  • DNase I footprinting
  • Nick Translation

Properties and Usage

Unit Definition

One unit is defined as the amount of enzyme which will completely degrade 1 µg of pBR322 DNA in 10 minutes at 37°C in DNase I Reaction Buffer.

Complete degradation is defined as the reduction of the majority of DNA fragments to tetranucleotides or smaller.

Reaction Conditions

1X DNase I Reaction Buffer
Incubate at 37°C

1X DNase I Reaction Buffer:
10 mM Tris-HCl
2.5 mM MgCl2
0.5 mM CaCl2
pH 7.6 @ 25°C

Usage Concentration

2,000 units/ml

Storage Temperature


Storage Conditions

10 mM Tris-HCl
2 mM CaCl2
50% Glycerol
pH 7.6 @ 25°C

Heat Inactivation

75°C for 10 min

Heat Inactivated


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.
  • RNase Activity (2 Hour Digestion):
    The product is tested in a reaction containing a RNA substrate.  After incubation for 2 hour there is no detectable degradation of the RNA substrate as determined by gel electrophoresis.

Supporting Documents

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]
The following is a list of Safety Data Sheet (SDS) that apply to this product to help you use it safely.
The Product Summary Sheet, or Data Card, includes details for how to use the product, as well as details of its formulation and quality controls. The following file naming structure is used to name the majority of these document files: [Catalog Number]Datasheet-Lot[Lot Number]. For those product lots not listed below, please contact NEB at or fill out the Technical Support Form for appropriate document.


  1. EDTA should be added to a final concentration of 5 mM to protect RNA from being degraded during enzyme inactivation (3).


  1. Kunitz, M. (1950). J. Gen. Physiol . 33, 349-362.
  2. Vanecko, S. and laskowski, M. (1961). J. Biol. Chem . 236, 3312-3316.
  3. Huang, Z. et al. (1996). Biotechniques . 20, 1012-1020.
  1. What is the specific activity of DNase I(RNase-free)?
  2. Will DNase I work in NEB buffers 1-4?
  3. What is the best way to remove DNase I from my reaction?
  4. Will DNase I work in CutSmart buffer?
  1. A Typical DNase I Reaction Protocol (M0303)