Nuclease


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nuclease

[′nü·klē‚ās]
(biochemistry)
An enzyme that catalyzes the splitting of nucleic acids to nucleotides, nucleosides, or the components of the latter.

Nuclease

 

a phosphodiesterase enzyme that splits nucleic acids into mononucleotides and oligonucleotides.

Nucleases are widely distributed in the cells of microorganisms, plants, and animals. These enzymes are especially abundant in pancreatic juice and in the saliva of mammals and man. A distinction is made between 3′ and 5′ nucleases, depending on whether the enzyme splits the phosphodiester bonds of the nucleic acid to form nucleotides that contain phosphoric acid residues on the 3’- or 5’-carbon of the carbohydrate fragment. The terminal mononucleotides are separated by exonucleases; nucleases that split bonds within the polynucleotide chain are called endonucleases. Ribonucleases and deoxyribonucleases are distinguished according to whether they split ribonucleic or deoxyribonucleic acids. Nonspecific nucleases are able to split chains of both types of acids.

Nucleases are proteins—usually basic—with a comparatively low molecular weight; for example, the pancreatic ribonuclease molecule consists of 124 amino-acid residues. The biological function of nucleases is to digest and split nucleic acids that are foreign to the organism, for example, nucleic acids of invasive viruses. This is the rationale for using nucleases to treat certain viral diseases. Nucleases participate in the repair of deoxyribonucleic acid (DNA) by eliminating the fragmented portions of the DNA molecule from the polynucleotide chain. Nucleases also appear to play a major role in regulating the synthesis and decomposition of nucleic acids in cells. A nuclease enzyme can be used in laboratories to free preparations from a specific nucleic acid, to determine the structure of nucleic acids, and to study the mechanism of nucleic acid decomposition and synthesis.

REFERENCE

Shapot, V. S. Nukleazy. Moscow, 1968.

I. B. ZBARSKII

References in periodicals archive ?
Novel genetic tools allowing for targeted changes via homologous recombination with higher frequency have been designed, including zinc finger nucleases (ZFN), transcription activator-like effector nucleases (TALEN), and clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9.
The researchers, however, feel that further studies are essential to understanding the functional relationship between the PAM recognition and the SaCas9 nuclease activity.
Novel genome editing tools, also referred to as genome editing with engineered nuclease (GEEN) technologies, allow cleavage and rejoining of DNA molecules in specified sites to successfully modify the hereditary material of cells.
[27] Ma, N., et al., Transcription activator-like effector nuclease (TALEN)-mediated gene correction in integration-free [beta]-thalassemia induced pluripotent stem cells.
Other reported approaches designed for improving production of genetically modified animals targeting specific genomic sequences are zinc-finger nuclease (ZFN) [3-5] and transcription activator-like effector nucleases (TALENs) [6,7], which are potential next-generation platforms for customized genomic editing and transgenic animals production, as well as generation of transgenic cells lines in vitro.
During specificity, heat treatment at 80 degC for 20 minutes of soil DNA sample prior PCR improved detection level and nuclease enzymes became inactivated.
In contrast, ZFNs and TALENs are fusion proteins of designed DNA-binding sequences and the Fok I nuclease cleavage domain.
The complex triggers the cleavage of target DNA when sufficient RNA-DNA complementarity is available for the activation of HNH and RuvC nuclease domains.
Uropathogenic specific protein gene, highly distributed in extraintestinal uropathogenic Escherichia coli, encodes a new member of H-N-H nuclease superfamily.
Recently, the presence of a mitochondrial nuclease, which migrates to the nucleus in response to apoptotic stimuli (8,9) has been identified, both in species of Trypanosoma (T.