Description
Topoisomerase I relaxes supercoiled DNA molecules. The enzyme initiates transient breakages and rejoins of phosphodiester bonds in superhelical turns of closed-circular DNA. Enzyme activity is independent of right-and left-handed superhelices.
Abbr
TOPO I, Recombinant (E. coli)
Product Overview
Topoisomerase I (E. coli) catalyzes the relaxation of negatively supercoiled DNA. 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 97 kDa protein.
Form
50 mM KCl, 10 mM Tris-HCl (pH 7.5), 35 mM (NH4)2SO4, 0.1 mM EDTA, 1 mM DTT and 50% glycerol.
Concentration
5,000 units/ml
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 in a total reaction volume of 25 μl. DNA supercoiling is assessed by agarose gel electrophoresis in the absence of ethidium bromide.
Synonyms
Topoisomerase I; EC 5.99.1.2; type I DNA topoisomerase; untwisting enzyme; relaxing enzyme; nicking-closing enzyme; swivelase; ω-protein; deoxyribonucleate topoisomerase; topoisomerase; type I DNA topoisomerase; DNA topoisomerase; TOPO I
