|Human Topoisomerase I (Top1)|
|TG2005H-RC1||250 Units||$205.00||Add to Cart|
|TG2005H-RC2||500 Units||$305.00||Add to Cart|
|TG2005H-RC3||3000 Units (300 u/ul)||$915.00||Add to Cart|
Human Topo I Product Background
TopoGEN now offers a high purity and catalytically active Top1 Enzyme overexpressed in the baculovirus system and purified to single band homogeneity. These preparations are cheaper than native topo I made from human tissue and offer excellent purity and high specific activity. In addition, the 100 kDa form of recombinant topo I is stable and is less prone to proteolysis, relative to the native protein from human cells.
Quality Control Tests:
Relaxation assays were carried out in a final volume of 25 µl in recombinant topo I reaction buffer (10X reaction buffer, supplied with this product is: 100 mM Tris-Cl, pH 7.9, 1.5 M NaCl, 1% BSA, 1 mM Spermidine, 50% glycerol). Supercoiled plasmid DNA was included at 0.25 µg/reaction. Reactions terminated with 5 µl (per 20 µl reaction volume) of stop buffer (5% sarkosyl, 0.0025% bromophenol blue, 25% glycerol). Reaction products were analyzed on a 1% native agarose gel. Under these conditions, relaxation activity is easily detectable (typically we see 10-40 units of activity per ul). A typical titration is shown below:
10X assay buffer and dilution buffer is included. These may be purchased separately as TGS 10X Topo I Assay Buffer (TG4095).
The enzyme is shipped on dry ice and should be stored at -20°C. It has a life-time of about 6 months when stored under optimal conditions. Repeat freeze/thaw cycles will accelerate loss.