Deoxyribonucleases (DNases) | Thermo Fisher Scientific

stylized illustration representing Deoxyribonucleases (DNases)

Enzymes that hydrolyze phosphodiester bonds, used in various molecular biology applications.

Properties of deoxyribonucleases (DNases)

Nuclease	Applications	Substrate	Specificity, polarity of cleavage	Reaction products
DNase I, RNase-free DNase I, RNase-free with MnCl₂ DNase I, RNase-free, HC	Preparation of DNA-free RNA Removal of template DNA following in vitro transcription Preparation of DNA-free RNA prior to RT-PCR DNA labeling by nick-translation DNase foot printing	ssDNA¹ dsDNA DNA in RNA-DNA hybrids	Sequence and base unspecific	5’-dNMPs 5’-oligonucleotides
*Endonuclease IV, E. coli* (Endo IV)**	Studies of DNA damage and repair Single cell electrophoresis SNP analysis	AP DNA	5' to an abasic site, 3'→ 5' exonuclease	DNA with nicks 5' to AP sites
*Endonuclease V, T. maritima* (Endo V)**	High-throughput methods for mutation research Studies of mutagenesis and DNA repair Mismatch cleavage Genotyping	Deaminated DNA	Second phosphodiester bond 3' to the lesion	Nicked DNA²
Exonuclease I (Exo I)	PCR product clean-up Removal of ssDNA from nucleic acid mixtures	ssDNA³	3'→ 5'	5'-dNMPs 5'-terminaldinucleotides
Exonuclease III (Exo III)	Creation of unidirectional deletions in DNA fragments Generation of ssDNA for sequencing Site-directed mutagenesis Preparation of strand specific probes	dsDNA (with nicks, blunt ends, 5’-overhangs)⁴	3'→ 5'	5'-dNMPs ssDNA
		AP DNA	5' to an abasic site	DNA with nicks 5' to AP sites
		RNA in RNA-DNA hybrids	3'→ 5'	NMP's
		DNA with 3’-phosphorylated ends	N/A	3'-OH ends of DNA
Exonuclease VII	Bi-directional exonuclease activity with single-stranded specificity Removal of ssDNA from nucleic acid mixtures	ssDNA³	3'→ 5' 5'→ 3'	Oligonucleotides
Exonuclease, T7 Gene 6	Controlled stepwise digestion of double-stranded DNA from the 5' termini Generation ssDNA templates for sequencing or SNP analysis	dsDNA and RNA:DNA hybrids	5'→ 3'	Oligonucleotides 5'-dNMPs
Lambda Exonuclease	Generation of ssPCR products for sequencing, SSCP analysis, rolling circle amplification Producing ssDNA from dsDNA fragments	5'-phosphorylated dsDNA⁵	5'→ 3'	5'-dNMPs

1 - ssDNA is cleaved slower than dsDNA.

2 - when enzyme is in excess, complimentary strand is also nicked, generating a double-stranded break.

3 - does not cleave DNA chains with terminal 3'-phosphoryl or acetyl groups. Not suitable for removing 3'- overhang ends of dsDNA - this activity is greatly reduced.

4 - not active on 3'-overhang ends of DNA that are at least 4 base long or on phosphorothioate-linked nucleotides or ssDNA.

5 - selectively digests the 5'-phosphorylated strand of dsDNA. Exhibits greatly reduced activity on ssDNA and non-phosphorylated DNA; has limited activity at gaps in DNA and no activity at nicks.