Topo I, Wild Type

Liquid. In 100 mM KCl, 20 mM Tris-HCl, 1 mM DTT, 200 µM EDTA, 20% glycerol, pH 7.9. AVOID FREEZE/THAW CYCLES. Human DNA topoisomerase I (Topo I) is a monomeric protein of 765 amino acids encoded by a single-copy gene. It catalyzes the relaxation of both positive and negative supercoiled DNAs without the requirement of energy. In addition to DNA replication and transcriptional activation, DNA topoisomerase I also plays a major role in pre-mRNA splicing, cell cycle and other gene regulatory pathways during cell growth and development. Since Topo I can cause large amounts of single-strand DNA breaks it is an important target for antitumor agents. One unit= 1 ng protein. Specific activity: 1 unit/ng protein. 0.1-1 unit (ng) is sufficient for relaxing 0.5 µg of pBR322 supercoiled DNA in a 20 µl reaction. Purity: ≥95% by SDS-PAGE . M.W. 85,000.