Deoxyribonuclease II (, ''

DNase 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 ...

II'', ''pancreatic DNase II'', ''deoxyribonucleate 3'-nucleotidohydrolase'', ''pancreatic DNase II'', ''acid deoxyribonuclease'', ''acid DNase'') is an endonuclease that hydrolyzes phosphodiester linkages of

deoxyribonucleotide A deoxyribonucleotide is a nucleotide that contains deoxyribose. They are the monomeric units of the informational biopolymer, deoxyribonucleic acid (DNA). Each deoxyribonucleotide comprises three parts: a deoxyribose sugar (monosaccharide), a ni ...

in native and denatured

DNA Deoxyribonucleic acid (; DNA) is a polymer composed of two polynucleotide chains that coil around each other to form a double helix. The polymer carries genetic instructions for the development, functioning, growth and reproduction of al ...

, yielding products with 3'-phosphates and 5'-hydroxyl ends, which occurs as a result of single-strand cleaving mechanism. As the name implies, it functions optimally at

acid An acid is a molecule or ion capable of either donating a proton (i.e. Hydron, hydrogen cation, H+), known as a Brønsted–Lowry acid–base theory, Brønsted–Lowry acid, or forming a covalent bond with an electron pair, known as a Lewis ...

pH because it is commonly found in low pH environment of

lysosome A lysosome () is a membrane-bound organelle that is found in all mammalian cells, with the exception of red blood cells (erythrocytes). There are normally hundreds of lysosomes in the cytosol, where they function as the cell’s degradation cent ...

s. The action of DNase occurs in three phases. The initial phase introduces multiple nicks in the

phosphodiester backbone Deoxyribonucleic acid (; DNA) is a polymer composed of two polynucleotide chains that coil around each other to form a double helix. The polymer carries genetic instructions for the development, functioning, growth and reproduction of all ...

. The second phase produces acid-soluble nucleotides. The third phase, which is the terminal phase, consists of hyperchromic shift resulting from reduction of oligonucleotides. There are several known

s II, including: * DNase II alpha (usually known as DNase II), which is thought to be ubiquitously expressed in human tissue. It has been shown that a mutation in this enzyme of mice leads to DNA degradation by apoptosis. * DNase II beta (also called DLAD, or DNase II-Like Acid DNase), which is mainly expressed in the

eye lens The lens, or crystalline lens, is a transparent biconvex structure in most land vertebrate eyes. Relatively long, thin fiber cells make up the majority of the lens. These cells vary in architecture and are arranged in concentric layers. New laye ...

and

salivary glands The salivary glands in many vertebrates including mammals are exocrine glands that produce saliva through a system of Duct (anatomy), ducts. Humans have three paired major salivary glands (Parotid gland, parotid, Submandibular gland, submandibula ...

. One of its functions is to clear DNA from eye lens. Low levels have also been detected in the lung, prostate and lymph nodes. Deficiency of this enzyme in mice lead to the development of cataracts.

References

External links

* EC 3.1.22 {{3.1-enzyme-stub