Human Topoisomerase 1 Enzyme

Human topoisomerase 1 is supplied in Dilution Buffer (1) at a minimum concentration of 30ng/µl, corresponding to at least 30 U/µl. 1 U of hTOP1 relaxes 0.5 µg of supercoiled pUC19 when incubated in 1xReaction Buffer (2) and 150 mM NaCl for 30 minutes at 37°C – see Documentation.

The enzyme preparation is highly stable and recommended for activity assays, including cleavage-ligation experiments, equilibrium, nicking, and relaxation assays.

The enzyme is supplied together with
(1) Dilution Buffer: 5 mM Tris-HCl pH 7.5, 400 mM NaCl, 1mM DTT, 50% glycerol
(2) Reaction Buffer 10x: 100 mM Tris-HCl pH 7.5; 50 mM MgCl2, 50 mM CaCl2; 50 µg/ml BSA
• Nucleases-free water
• 1M NaCl

Recombinant non-tagged human topoisomerase 1 is prepared by overexpressing the enzyme in Saccharomyces cerevisiae followed by purification by affinity chromatography adapted from Knudsen et al, J. Chrom. 1996, DOI: 10.1016/0378-4347(96)00152-1

The enzyme is shipped cooled by gel packs and must be stored at -18°C to -20°C upon arrival. The temperature must be controlled to avoid that the enzyme preparation solidifies. This would destroy the enzyme integrity and cause a drop of the human topoisomerase 1 activity. The enzyme has a lifetime of 12 months when stored under optimal conditions.

Certificate of Analysis for human topoisomerase 1

Safety Data Sheet for human topoisomerase 1 enzyme products

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2. Nitiss, J.L.; Soans, E.; Rogojina, A.; Seth, A.; Mishina, M. Topoisomerase assays.Curr. Protoc. Pharmacol.2012,Chapter 3, Unit 3.3., doi:10.1002/0471141755.ph0303s57.3.

3. Andersen, M.B.; Tesauro, C.; Gonzalez, M.; Kristoffersen, E.L.; Alonso, C.; Rubiales, G.; Coletta, A.; Frøhlich, R.; Stougaard, M.; Ho, Y.-P.; et al. Advantages of an Optical Nanosensor System for Mechanistic Analysis of a Novel Topoisomerase I Targeting Drug: A case story.Nanoscale2016, 1886–1895, doi:10.1039/C6NR06848K.

4. Pommier, Y. Topoisomerase I inhibitors: camptothecins and beyond.Nat. Rev. Cancer2006,6, 789–802, doi:10.1038/nrc1977.

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