Désoxyribonucléase

Deoxyribonuclease (DNase, for short) refers to a group of glycoprotein endonucleases which are enzymes that catalyze the hydrolytic cleavage of phosphodiester linkages in the DNA backbone, thus degrading DNA. The role of the DNase enzyme in cells includes breaking down extracellular DNA (ecDNA) excreted by apoptosis, necrosis, and neutrophil extracellular traps (NET) of cells to help reduce inflammatory responses that otherwise are elicited. A wide variety of deoxyribonucleases are known and fall into one of two families (DNase I or DNase II), which differ in their substrate specificities, chemical mechanisms, and biological functions. Laboratory applications of DNase include purifying proteins when extracted from prokaryotic organisms. Additionally, DNase has been applied as a treatment for diseases that are caused by ecDNA in the blood plasma. Assays of DNase are emerging in the research field as well. The two main types of DNase found in animals are known as deoxyribonuclease I (DNase I) and deoxyribonuclease II (DNase II). These two families have subcategories within them. The first set of DNases is DNase I. This family consisted of DNase I, DNase1L1, DNase 1L2, and DNase1L3. 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 DNase I family requires Ca2+ and Mg2+ cations as activators and selectively expressed. In terms of pH, the DNAses I family is active in normal pH of around 6.5 to 8. The second set of DNAases is DNase II. This family consisted of DNase II ɑ and DNase II ꞵ. Like DNAase I, DNAase II cleaves DNA to form two oligonucleotide-end products with 5’-hydroxy and 3’-phospho ends. This type of DNAase is more widely expressed in tissues due to high expression in macrophages but limited cell-type expression. Unlike DNAase I, they do not need Ca2+ and Mg2+ cations as activators. In terms of pH, the DNAase II family is expressed in acidic pH.