BD Pharmingen™ Purified Mouse Anti-Human DNA Topoisomerase I

DNA damage may be caused by various environmental factors, including radiation, mutagenic chemicals and copy errors which occur during DNA replication. The correction of DNA damage, so called "proofreading" functions of the cell, is achieved by numerous excision-repair enzymes. Topoisomerases alter the helical structure of DNA by introducing the transient breaking and rejoining of DNA strands, allowing other excision-repair enzymes to correct DNA errors. Topoisomerase I (Topo I) is a ubiquitous, soluble enzyme whose expression is fairly constant throughout the cell cycle. The related enzyme, Topo II, is a primarily insoluble structural protein whose expression varies between cell types and during the cell cycle. In addition to its role in DNA mismatch repair, Topo I displays kinase activity, phosphorylating serine-arginine rich (SR) splicing factors, and perhaps regulating gene expression by changing the splicing pattern of structural genes. DNA Topo I migrates at a molecular weight of 100 kDa in SDS-PAGE. Clone C-21 recognizes human DNA Topoisomerase I. The antibody is routinely tested by western blot analysis of A-431 cell lysates.