Star activityis the relaxation or alteration of the specificity ofrestriction enzymemediated cleavage ofDNAthat can occur under reaction conditions that differ significantly from those optimal for the enzyme. The result is typically cleavage atnon-canonicalrecognition sites, or sometimes complete loss of specificity.
Differences which can lead to star include lowionic strength,highpH,and high (> 5%v/v)glycerolconcentrations.[1]The latter condition is of particular practical interest, since commercial restriction enzymes are usually supplied in abuffercontaining a substantial amount of glycerol (50% v/v is typical), meaning insufficient dilution of the enzyme solution can cause star activity; this problem most often arises during double or multiple digests. Star activity can happen because of presence ofMg2+,as is seen inHindIII,for example.
The term star activity was introduced by Mayer[2]who characterized the modified activity inEcoRI.
External links
edit- Star Activity-New England Biolabs
- Star Activity (Relaxation of Specificity)- Fermentas
- Star activity of restriction enzymes- a detailed list from TaKaRa
- Wei, H; Therrien, C; Blanchard, A; Guan, S; Zhu, Z (2008)."The Fidelity Index provides a systematic quantitation of star activity of DNA restriction endonucleases".Nucleic Acids Research.36(9): e50.doi:10.1093/nar/gkn182.PMC2396408.PMID18413342.
References
edit- ^Robinson, CR; Sliger, SG (1993). "Molecular Recognition Mediated by Bound Water: A Mechanism for Star Activity of the Restriction Endonuclease EcoRI".Journal of Molecular Biology.234(2): 302–306.doi:10.1006/jmbi.1993.1586.PMID8230215.
- ^Mayer, Hubert (1978)."Optimization of the EcoRI*-activity of EcoRI endonuclease".FEBS Lett.90(2): 341–44.doi:10.1016/0014-5793(78)80400-1.PMID352725.
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