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Cat. No.: EXN1-1500 (for 1500U)

Cat. No.: EXN1-15k (for 15KU)

Description

Exonuclease I has exonuclease activity that degrades single-stranded DNA from 3' - 5' direction, and can gradually release 5' monophosphate of DNA, leaving a complete 5' terminal dinucleotide. The enzyme comes from the plasmid of the E.coli exo I gene and is obtained by recombinant expression and purification. Exonuclease I is mainly used to degrade digestion primers after PCR amplification. The enzyme has no activity for double-stranded DNA and 3' OH terminal DNA strand blocked by phosphoryl or acetyl groups.

Unit Definition

One unit is defined as the amount of enzyme required to catalyze the release of 10 nmol acid-soluble nucleosides within 30 minutes at 37°C.

Components

1500U

Exonuclease I(20 U/μl):    75 μl
10×ExoI Buffer:    1 ml

Applications

• Removal of primers from PCR mixtures

• Detection of the presence of single-stranded DNA containing 3' hydroxy terminal

• Removal of single-stranded DNA containing 3' hydroxy terminal from the nucleic acid mixture

• PCR mutation reaction with large primers in the single tube before sequencing

Storage

The minimum shelf life is 3 years at -20°C.

Note

• 1 × ExoI Buffer: 67mM Glycine-KOH pH 9.5, 6.7mM MgCl₂, 10mM 2-mercaptoethanol. The enzyme is also active in conventional PCR Buffer.

• The enzyme cannot cut double-stranded DNA, so single-stranded DNA containing a secondary structure needs to be denatured before it can be completely digested.

• The optimal reaction temperature of the enzyme is 37°C, and it can be inactivated at 80°C for 20 minutes.