Micrococcal nuclease
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Micrococcal Nuclease (S7 Nuclease) is a 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.
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[edit] 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 Ca2+ and the pH optimum varies according to Ca2+ concentration (Heins et al. 1967). The enzyme is therefore easily inacitvated by EDTA.
[edit] Source
This enzyme is the extracellular nuclease of Staphylococcus aureus. Two strains, V8 and Foggi, yield almost identical enzymes (Cusumano et al. 1968). A common source is E.coli cells carrying a cloned nuc gene encoding Staphylococcus aureus extracellular nuclease (micrococcal nuclease).
[edit] 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.
[edit] References
- http://www.fermentas.com/catalog/modifyingenzymes/nucleasemicrococcal.htm
- http://www.worthington-biochem.com/NFCP/default.html
- Cusumano, C., Taniuchi, H., and Anfinsen, C.: Staphylococcal Nuclease (Foggi Strain). I. Order of Cyanogen Bromide Fragments and a "Fourth" Histidine Residue , J Biol Chem 243, 4769, 1968
- Heins, J., Suriano, J., Taniuchi, H., and Anfinsen, C.: Characterization of a Nuclease Produced by Staphylococcus aureus, J Biol Chem 242, 1016, 1967
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