Deoxyribonuclease
DNase I cleaves DNA to form two oligonucleotide-end products with 5’-phospho and 3’-hydroxy ends and is produced mainly by organs of the digestive system.
The cleavage pattern of DNase II is altered in the presence of Dimethyl sulfoxide(DMSO), which significantly affects the structure of DNA.
The interior of the U-shaped clamp is largely electropositive, capable of binding negatively-charged DNA.
)[8] Some DNases are fairly indiscriminate about the DNA sequence at which they cut, while others, including restriction enzymes, are very sequence-specific.
DNase I catalyzes nonspecific DNA cleavage by nicking phosphodiester linkages in one of the strands.
It is common for the degraded and fragile cell membrane to be lysed, 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 to break it down.
As a result, several studies of inflammatory diseases have found that there are high concentrations of ecDNA in blood plasma.
Illnesses that result from DNA residue in blood have been targeted using the "breaking-down properties" of DNase.
[15] Cystic fibrosis is a genetic disorder that affects the production of mucus, sweat, and digestive fluids, causing them to become more viscous rather than lubricant.
Specifically, DNase I, also known as FDA approved drug Pulmozyme (also known as dornase alfa) is used as a treatment to increase pulmonary function.
Other respiratory illness such as asthma,[16] pleural empyema,[12] and chronic obstructive pulmonary disease have also been found to be positively affected by DNases properties.
Furthermore, recent studies show that intrapleural tissue plasminogen activator (tPA), a protein that is responsible for the breakdown of blood clots, combined with deoxyribonuclease increase pleural drainage, decreases hospital length of stay, and decreases the need for surgery in parapneumonic effusions and empyema.
It has been suggested that their difficulty might be due to the inability for the enzyme to break down the cell membrane of chromatin.
Studies have shown conflicting results on this treatment, however, further research is being conducted to examine the therapeutic benefits of DNase I.
High levels of DNA are found to be in cancer patients' blood, suggesting that DNase I might be a possible treatment.
Several mice studies have shown positive results in anti-tumor progression utilizing intravenous DNase I.
Single Radial Enzyme Diffusion (SRED) This simple method for DNase I activity measurement was introduced by Nadano et al. and is based on the digestion of DNA in the agarose gel by DNase, which is present in samples punched into the gel.
[14] DNase activity is represented by the size of a dispensed circular well in an agarose gel layer, in which DNA stained by ethidium bromide is uniformly distributed.
After the incubation, a circular dark zone is formed as the enzyme diffuses from the well radially into the gel and cleaves DNA.
SRED underwent many modifications, which led to an increase in sensitivity and safety, such as the replacement of ethidium bromide with SYBR Green I or other DNA gel stains.
The method was adjusted from a colorimetric endpoint enzyme activity assay based on the degradation of a DNA/methyl green complex.
