|SMART accession number:||SM00476|
|Description:||Deoxyribonuclease I catalyzes the endonucleolytic cleavage of double-stranded DNA. The enzyme is secreted outside the cell and also involved in apoptosis in the nucleus.|
|Interpro abstract (IPR008185):|
Deoxyribonuclease I (DNase I) (EC 18.104.22.168) [(PUBMED:3713845)] is a vertebrate enzyme which catalyzes the endonucleolytic cleavage of double-stranded DNA to 5'- phosphodinucleotide and 5'-phosphooligonucleotide end-products. DNase I is an enzyme involved in DNA degradation; it is normally secreted outside of the cell but seems to be able to gain access to the nucleus where it is involved in cell death by apoptosis [(PUBMED:8428592)].
As shown in the following schematic representation, DNase I is a glycoprotein of about 260 residues with two conserved disulphide bonds.
DNase I has a pH-optimum around 7.5 and requires calcium and magnesium for full activity. It causes single strand nicks in duplex DNA. A proton acceptor-donor chain composed of an histidine and a glutamic acid produce a nucleophilic hydroxyl ion from water, which cleaves the 3'-P-O bond [(PUBMED:3352748)].
DNase I forms a 1:1 complex with G-actin, resulting in the inhibition of DNase activity and loss of the ability of G-actin to polymerise into fibres [(PUBMED:2395459)].
DNase I has been used in the treatment of lung problems in patients with cystic fibrosis: here it acts by degrading DNA found in purulent lung secretions, reducing their viscosity and making it easier for the patient to breathe [(PUBMED:2251263)].
The sequence of DNase I is evolutionary related to that of human muscle-specific DNase-like protein and human proteins DHP1 and DHP2. However, the first disulphide bond of DNase I is not conserved in these proteins.
|GO process:||DNA catabolic process (GO:0006308)|
|GO function:||deoxyribonuclease activity (GO:0004536)|
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