Micrococcal nuclease 2848926 215805024 2008-05-29T20:03:18Z Aciel 220307 '''Micrococcal Nuclease''' (S7 [[Nuclease]] or MNase) is an [[endo]]-[[exonuclease]] that preferentially digests [[single-stranded]] [[nucleic acids]].The rate of cleavage is 30 times greater at the 5' side of A or T than at G or C and results in the production of [[mononucleotides]] and [[oligonucleotides]] with terminal 3'-[[phosphates]]. The enzyme is also active against [[double-stranded DNA]] and [[RNA]] and all sequences will be ultimately cleaved. ==Characteristics== The [[enzyme]] has a [[molecular weight]] of 16.9kDa. The [[pH]] optimum is reported as 9.2. The [[enzyme]] activity is strictly dependent on Ca<sup>2+</sup> and the [[pH]] optimum varies according to Ca2+ concentration.<ref>{{cite journal |author=Heins JN, Suriano JR, Taniuchi H, Anfinsen CB |title=Characterization of a nuclease produced by Staphylococcus aureus |journal=J. Biol. Chem. |volume=242 |issue=5 |pages=1016–20 |year=1967 |pmid=6020427 |doi=}}</ref> The [[enzyme]] is therefore easily inacitvated by [[EDTA]]. ==Source== This enzyme is the extracellular [[nuclease]] of [[Staphylococcus aureus]]. Two strains, V8 and Foggi, yield almost identical enzymes.<ref>{{cite journal |author=Cusumano CL, Taniuchi H, Anfinsen CB |title=Staphylococcal nuclease (Foggi strain). I. Order of cyanogen bromide fragments and a "fourth" histidine residue |journal=J. Biol. Chem. |volume=243 |issue=18 |pages=4769–77 |year=1968 |pmid=5687719 |doi=}}</ref> A common source is ''[[Escherichia coli|E.coli]]'' cells carrying a cloned nuc [[gene]] encoding [[Staphylococcus]] aureus extracellular nuclease (micrococcal nuclease). ==Applications== *Hydrolysis of [[nucleic acids]] in crude cell-free extracts. *Sequencing of [[RNA]]. *Preparation of rabbit [[reticulocytes]] lysates *Studies of [[chromatin]] structure. *Remove [[nucleic acids]] from [[protein]] preparation allowing for folding and structure-function studies. ==References== <references/> *http://www.fermentas.com/catalog/modifyingenzymes/nucleasemicrococcal.htm *http://www.worthington-biochem.com/NFCP/default.html *http://www.fermentas.com/pdf/msds/en0181_eu.pdf#search=%22micrococcal%20nuclease%22 - A material and safety data sheet for the product ==External links== * {{MeshName|Micrococcal+Nuclease}} * {{EC number|3.1.31.1}} {{Nucleases}} [[Category:Proteins|Proteins]] [[Category:Molecular biology]]