Purified Enzyme
Source: Topogen Inc.
Human topoisomerase I is purified from freshly extracted human placenta and purified to homogeneity...
Human topoisomerase I is purified from freshly extracted human placenta and purified to homogeneity. The final fraction of enzyme contains a single polypeptide band of 100 kDa and is devoid of contaminating nuclease activity; however, with time there is spontaneous degradation of the 100 kDa form. The enzyme is not certified for use in Western blotting applications.
A unit of topo I can relax 0.25 µg DNA in 15 minutes at 37°C. The enzyme is supplied at a nominal concentration of approximately 2 units/ul. The final fraction of topoisomerase I is a Phenylsepharose column pool and is in the following buffer: 10 mM Tris-Cl, pH 7.1, 0.6 M ammonium sulfate, 1 mM EDTA, 0.5 mM PMSF, 1 mM mercaptoethanol, 10% glycerol. The enzyme is stable in this buffer at –70°C. In general the enzyme is less stable when diluted.
Topogen Inc., P.O. Box 20607 Columbus, OH 43220. Tel: 800-867-6436; Fax: 800-233-8676.