DescriptionFspEI, an EpiMark® validated product, is a modification-dependent endonuclease which recognizes CmC sites and generates a double-stranded DNA break on the 3´ side of the modified cytosine at N12/N16. Recognized cytosine modifications include C5-methylation (5-mC) and C5-hydroxymethylation (5-hmC) (1).
This enzyme is provided with an Enzyme Activator Solution which may be used for efficient digestion by FspEI.
The most common epigenetic modifications found in eukaryotic organisms are methylation marks at CpG or CHG sites. A subset of these modified sites are recognized and cleaved by FspEI.
At fully methylated CpG sites:
5´. . . C mC G G . . . 3´
3´. . . G G mC C . . . 5´
or CHG sites:
5´. . . C mC H G G . . . 3´
3´. . . G G D mC C . . . 5´
H = A or C or T (not G)
D = A or G or T (not C)
FspEI recognizes each hemi-methylated site individually and cleaves bidirectionally to generate 32 base or 31 base fragments, respectively. These fragments contain the central methylated site and have 4-base 5´ overhangs at each end. FspEI does not cleave unmodified DNA.
Product SourceAn E. coli strain that carries the synthetic FspEI gene from Frankia species EAN1pec.
The following reagents are supplied with this product:
|Store at (°C)||Concentration|
|Enzyme Activator Solution||30X|
|Purified BSA||-20||10 mg/ml|
Properties and Usage
Unit DefinitionOne unit is defined as the amount of enzyme required to digest 1 µg of pBR322 (dcm+) DNA in 1 hour at 37°C in a total reaction volume of 50 µl.
1X NEBuffer 4
Supplement with Purified BSA and 1X Enzyme Activator Solution
Incubate at 37°C
1X NEBuffer 4:
50 mM Potassium Acetate
20 mM Tris-acetate
10 mM Magnesium Acetate
1 mM DTT
pH 7.9 @ 25°C
Activity in NEBuffersNEBuffer 1.1: 10%
NEBuffer 2.1: 10%
NEBuffer 3.1: 10%
CutSmart® Buffer: 100%
10 mM Tris-HCl
300 mM NaCl
1 mM DTT
0.1 mM EDTA
500 μg/ml BSA
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.
- 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.
- 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.
- Zheng, Y. et al. (2010). Nucl. Acids Res. doi:10, 1093/nar/gkq327.
- U.S. Publication No. 2010-0167942 Unpublished observation