商品编号


EG-167



品牌


Excellgen



公司


Excellgen, Inc.



公司分类


DNA Modifying Enzymes



Size

500 Units

商品信息



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




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.




Source

An
E. coli
strain that carries the Vaccinia virus

H6R gene




Unit Definition


One unit of Vaccinia virus DNA Topoisomerase I will convert 1 ?g 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




Quality Control


The absence of exo- and endodeoxyribonucleases, non-specific DNase and RNase is confirmed by appropriate quality test.




Storage Condition


-20 °C