商品编号


EG-184



品牌


Excellgen



公司


Excellgen, Inc.



公司分类


DNA Modifying Enzymes



Size

100 Units

商品信息



Description


E. coli
Topoisomerase I has also been implicated in knotting and unknotting DNA and in linking complementary rings of single-stranded DNA into double-stranded rings. The intact holoenzyme is a 97K protein with three Zn(II) atoms in tertacysteine motifs near its carboxy-terminus. Topoisomerase I appears to reverse supercoiling by transiently breaking a segment of single-stranded DNA, passing an intact single- or double-stranded strand of DNA through the gate, then rejoining the broken segment.




Source

An
E. coli
strain that carries the
E. coli
topA gene




Unit Definition


One unit is defined as the amount of enzyme that catalyzes the relaxation of > 95% of 0.5 μg of pUC19 RF I (negatively supercoiled) DNA in 15 minutes at 37°C.



Components


E. coli Topoisomerase I:
5,000 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