Product Class: Nuclease


New size
recombinant unique buffer incubation temp heat inactivation
Catalog #SizeConcentration
M0338S20 units1,000 units/ml
M0338L100 units1,000 units/ml


XRN-1 is highly processive 5´→3´ exoribonuclease, requiring 5´ monophosphate. It also acts on 5´ monophosphate ssDNA with greatly reduced efficiency.

Product Source

Purified from E. coli carrying a plasmid overexpressing the yeast XRN-1 gene (1).

Reagents Supplied

The following reagents are supplied with this product:

Store at (°C)Concentration
NEBuffer™ 3-2010X

Properties and Usage

Unit Definition

One unit is defined as the amount of enzyme that digests 1 µg of phosphorylated yeast RNA in 60 minutes at 37°C.

Reaction Conditions

1X NEBuffer 3
Incubate at 37°C

1X NEBuffer™ 3:
100 mM NaCl
50 mM Tris-HCl
10 mM MgCl2
1 mM DTT
pH 7.9 @ 25°C

Storage Temperature


Storage Conditions

20 mM Tris-HCl
500 mM NaCl
2 mM DTT
0.1 mM EDTA
50% Glycerol
0.1% Triton® X-100

Heat Inactivation

70°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.
  • Endonuclease Activity (Circular Single Stranded DNA):
    The product is tested in a reaction containing circular single stranded DNA. After incubation the percent cleaved is determined by agarose gel electrophoresis.
  • 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.
  • 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 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. We recommend adding Murine RNase Inhibitor (NEB #M0314) in your reaction at 1 unit/µl to prevent non-specific RNA degradation.


  1. Stevens, A (1980). Biol. Chem. 255, 3080-3085.
  1. What is the molecular weight of XRN-1?
  2. Is XRN-1 a tagged protein?
  3. Can XRN-1 digest ssDNA containing 5’ monophosphates?
  4. Is XRN-1 identified with other names in the literature?
We strongly recommend wearing gloves, using nuclease-free tubes and reagents, and thoroughly cleaning pipettes and bench surfaces to avoid RNase contamination.