Exonuclease I (E. coli)

Description:
Exonuclease I cleaves single-stranded DNA in the 3' -> 5' direction, releasing 5'-mono/di-nucleotides and leaving double-stranded DNA molecules and the 5'-terminus intact. The enzyme is processed through digestion and is inhibited by the presence of a 3'-terminal phosphate. Exonuclease I is tolerant of a wide-range of buffer conditions and can typically be added to reactions containing magnesium^(1-3).

Specific Activity: 185,000 U/mg

Application:
- Removal of residual ssDNA, including oligos, from reaction mixes

Source:
Purified from a strain of E. coli that expresses the recombinant Exonuclease I gene.

Supplied in:
10 mM Tris-HCl
100 mM NaCl
1 mM DTT
0.5 mM EDTA
50% Glycerol
pH 7.5 @ 25°C
 

10x Exonuclease I Buffer
670 mM Glycine-KOH
67 mM MgCl₂
100 mM 2-mercaptoethanol
(pH9.5@25°C)

Unit Definition:
One unit is defined as the amount of enzyme required to produce 10 nmol of acid-soluble total nucleotide in 30 minutes at 37°C.

Recommended Storage Condition: -20°C

Reference:
1. Lehman, I.R. and Nussbaum, A.L. (1964) J. Biol. Chem. 239, 2628.
2. Kushner, S.R. et al. (1971) Proc. Natl. Acad. Sci. USA 68, 824.
3. Kushner, S.R. et al. (1972) Proc. Natl. Acad. Sci. USA 69, 1366.