Deoxyribonuclease I [SEP] found in taxon
Deoxyribonuclease I
Deoxyribonuclease I (usually called DNase I), is an endonuclease coded by the human gene DNASE1.
DNase I is a nuclease that cleaves DNA preferentially at phosphodiester linkages adjacent to a pyrimidine nucleotide, yielding 5'-phosphate-terminated polynucleotides with a free hydroxyl group on position 3', on average producing tetranucleotides. It acts on single-stranded DNA, double-stranded DNA, and chromatin. In addition to its role as a waste-management endonuclease, it has been suggested to be one of the deoxyribonucleases responsible
, releasing unwanted DNA and the desired proteins. The resulting DNA-protein extract is highly viscous and difficult to purify, in which case DNase is added. The DNA is hydrolyzed but the proteins are unaffected and the extract can undergo further purification.
Types.
The two main types of DNase found in metazoans are known as deoxyribonuclease I and deoxyribonuclease II.
Other types of DNase include micrococcal nuclease.
Assay.
DNA absorbs UV light with a wavelength of maximal absorbance near 260 nm. This absorption is due