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A deoxyribonuclease (DNase, for short) is any enzyme that catalyzes the hydrolytic cleavage of phosphodiester linkages in the DNA backbone, thus degrading DNA. Deoxyribonucleases are one type of nuclease, a generic term for enzymes capable of hydrolising phosphodiester bonds that link nucleotides. A wide variety of deoxyribonucleases are known, which differ in their substrate specificities, chemical mechanisms, and biological functions. == Modes of action == Some DNases cut, or "cleave", only residues at the ends of DNA molecules (exodeoxyribonucleases, a type of exonuclease). Others cleave anywhere along the chain (endodeoxyribonucleases, a subset of endonucleases). Some are fairly indiscriminate about the DNA sequence at which they cut, while others, including restriction enzymes, are very sequence-specific. Some cleave only double-stranded DNA; others are specific for single-stranded molecules; and still others are active toward both. DNase enzymes can be inhaled using a nebuliser by cystic fibrosis sufferers. DNase enzymes help because white blood cells accumulate in the mucus, and, when they break down, they release DNA, which adds to the 'stickiness' of the mucus. DNase enzymes break down the DNA, and the mucus is much easier to clear from the lungs. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Deoxyribonuclease」の詳細全文を読む スポンサード リンク
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