| Description |
Vaccinia virus Topoisomerase I is a type I eukaryotic topoisomerase that removes both positive and negative superhelical turns (also called right- and left-handed supercoils) from covalently closed DNA. The product of the reaction is a covalently closed, circular DNA with fewer positive or negative superhelical turns. DNA Topoisomerase I does not absolutely require Mg2+ to function, although low concentrations of Mg2+ may increase activity
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| Applications |
Studying the effects of supercoiling on transcription in vitro.
Studying chromatin reconstitution in vitro.
Determining the degree of supercoiling of naturally occurring DNA.
Detecting mutant plasmids that differ in length by only one basepair.
Increasing restriction endonuclease digestion of resistant DNA substrates by unwinding the DNA coils to expose restriction sites.
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| Source |
An E. coli strain that carries the Vaccinia virus H6R gene |
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Unit Definition
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One unit of Vaccinia virus DNA Topoisomerase I will convert 1 µg of supercoiled DNA (Form I) to relaxed closed circular DNA (Form II) in 1 hour at 37°C under standard assay conditions. |
| Components |
Vaccinia virus Topoisomerase I: 10,000 units/ml in 10 mM Tris-HCl, 1 mM DTT, 0.1 mM EDTA, 50% glycerol, pH 7.5 @ 25°C
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| Quality Control |
The absence of exo- and endodeoxyribonucleases, non-specific DNase and RNase is confirmed by appropriate quality test.
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| Storage Condition |
-20 °C
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