Lambda Exonuclease

Description: It is a 5 ´ → 3 ´ nucleic acid exonuclease that specifically acts on DNA. It can selectively digest the phosphorylated double stranded DNA at the 5 ´ → 3 ´ end along the 5 ´ → 3 ´ direction. The enzyme digestion activity of single stranded DNA and non phosphorylated DNA at the 5 ´ end is low, and it cannot start digestion from the cut or notch of DNA. Lambda Exonuclease cuts the 5 ´ - 0H end about 20 times slower than the 5 ´ - P end. The enzyme digestion speed of single stranded DNA is about 100 times slower than that of double stranded DNA.

Application: To generate single strand PCR products for DNA sequencing; DNA single strand conformation polymorphism (SSCP) analysis; Roll ring amplification; Generate single stranded DNA from double stranded DNA fragments; Cloning of PCR products; Plasmid preparation and purification.

Source: Recombinant E.coli strain carrying E. coli lambda exonuclease gene.

Activity: Lambda exonuclease is a highly processive 5'→3' exodeoxyribonuclease, selectively digests the 5’-phosphorylated strand of double-stranded DNA, exhibits low activity on single-stranded DNA and non-phosphorylated DNA, and has limited activity at gaps in DNA.

Unit definition：One unit is defined as the amount of enzyme required to produce 10nmol of acid-soluble deoxyribonucleotide from double-stranded substrate in a total reaction volume of 50μl in 30minutes at 37°C in 1X Lambda Exonuclease Reaction Buffer with 1μg sonicated duplex [3H]-DNA.

Purity: It does not contain exonuclease, endonuclease, RNA enzyme or phosphatase of other kinds except Lambda Exonuclease.

Storage buffer：25mM Tris-HCl, 50mM NaCl, 1mM DTT, 0.1mM EDTA, 50% Glycerol, (pH8.0 @25°C)。

10X Reaction Buffer: 670mM Glycine-KOH, 25mM MgCl2, 500µg/ml BSA, (pH9.4 @25°C)。

Deactivation or inhibition: Add EDTA until the final concentration is at least 10mM, and incubate at 75°C for 10 minutes to inactivate lambda Exonuclease.

Storage condition: - 20°C, for 2 years.

Note: The best reaction temperature of Lambda Exonuclease is 37°C. It can be completely deactivated after incubating at 75°C for 10 minutes