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An enzyme (phosphodiesterase) that cleaves the internal phosphodiester bonds in a DNA molecule, thus producing DNA fragments of varying size. Cf.:exonuclease.
- micrococcal e. an enzyme, produced by a member of the genus Micrococcus, that cleaves nucleic acid s to oligonucleotides terminating in 3′-phosphates. SYN: micrococcal nuclease, spleen e., spleen phosphodiesterases.
- restriction e. one of many endonucleases isolated from bacteria that cleave or hydrolyze (cut) foreign double-stranded DNA chains at specific recognition sites defined by DNA sequences; these endonucleases have become standard laboratory devices for making specific cuts in DNA as a first step in deducing sequences and are sometimes referred to as a “chemical knife”; usually named by a three- or four-letter abbreviation of the name of the organism from which isolated ( e.g., EcoB from Escherichia coli, strain B). SYN: restriction enzyme.
- single-stranded nucleate e. e. S1 Aspergillus.
- spleen e. SYN: micrococcal e..
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en·do·nu·cle·ase -'n(y)ü-klē-.ās, -.āz n an enzyme that breaks down a nucleotide chain into two or more shorter chains by cleaving the internal phosphodiester bonds see RESTRICTION ENDONUCLEASE compare EXONUCLEASE
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en·do·nu·cle·ase (en″do-nooґkle-ās) any nuclease specifically catalyzing the hydrolysis of interior bonds of ribonucleotide or deoxyribonucleotide chains, producing poly- or oligonucleotides. Cf. exonuclease.Medical dictionary. 2011.