DNA Topoisomerases

Topoisomerases are ubiquitously expressed enzymes that overcome topological problems in genomic DNA, which can result from DNA replication, transcription and repair. Common problems such as knots and tangles are often resolved by topoisomerases.

Literature (2)
Gene Data

DNA Topoisomerase Inhibitors

Cat. No. Product Name / Activity
4219 Banoxantrone dihydrochloride
Prodrug topoisomerase II inhibitor
1100 Camptothecin
DNA topoisomerase inhibitor
3203 Celastrol
Topoisomerase II inhibitor
2688 CPT 11
DNA topoisomerase I inhibitor; antitumor
1467 Daunorubicin hydrochloride
DNA topoisomerase II inhibitor
3857 Dexrazoxane hydrochloride
Topoisomerase II inhibitor
2252 Doxorubicin hydrochloride
Antitumor antibiotic agent. Inhibits DNA topoisomerase II
1226 Etoposide
Topoisomerase II inhibitor
2684 SN 38
DNA topoisomerase I inhibitor; antitumor
6975 Teniposide
DNA topoisomerase II inhibitor; viral transduction enhancer
4562 Topotecan hydrochloride
DNA topoisomerase I inhibitor; Camptothecin (Cat. No. 1100) analog
3863 Trovafloxacin mesylate
Antibiotic; inhibits bacterial DNA topoisomerase IV and DNA gyrase

Topoisomerases are ubiquitously expressed enzymes that overcome topological problems in genomic DNA, which can result from DNA replication, transcription and repair. Common problems such as overwinding (positive supercoiling), knots and tangles are resolved by topoisomerases by catalyzing the breaking of one or two strands of DNA.

Topoisomerase type I enzymes cut just one strand of the DNA double helix, and therefore relax supercoiling of the DNA. Four genes encode Type I topoisomerases, which include nuclear topoisomerase I (TOP1) and mitochondrial topoisomerase I (TOP1MT). Type I enzymes can also be sub-divided into Types A and B based on their different catalytic mechanism for generating single DNA strand breaks. TOP1 and TOP1MT are both type 1B since they form 3'-phosphotyrosyl bonds. Camptothecin is a natural product inhibitor of TOP1 that has led to the discovery of derivatives that are clinically used anticancer drugs. Such inhibitors trap the enzyme in a cleavage complex with DNA. Type II topoisomerases (IIA and IIB) are particular important for the disentanglement of DNA, which is overcome by generating double stranded DNA breaks. Dysregulation of type II enzymes can therefore have a potentially significant genotoxic effect. There is a broad range of topoisomerase II inhibitors that are used clinically as therapeutically in cancer.

External sources of pharmacological information for DNA Topoisomerases :

    Literature for DNA Topoisomerases

    Tocris offers the following scientific literature for DNA Topoisomerases to showcase our products. We invite you to request* your copy today!

    *Please note that Tocris will only send literature to established scientific business / institute addresses.

    Huntington's Disease Research Product Guide

    Huntington's Disease Research Product Guide

    This product guide provides a background to Huntington's disease research and lists around 100 products for the study of:

    • Somatic Instability
    • Proteolysis and Inclusion Bodies
    • Transcriptional Dysregulation
    • Mitochondrial Dysfunction
    • Nuclear-Cytoplasmic Transport Interference
    • Excitotoxicity
    • Stem Cells
    Cell Cycle & DNA Damage Repair Poster

    Cell Cycle & DNA Damage Repair Poster

    In normal cells, each stage of the cell cycle is tightly regulated, however in cancer cells many genes and proteins that are involved in the regulation of the cell cycle are mutated or over expressed. This poster summarizes the stages of the cell cycle and DNA repair. It also highlights strategies for enhancing replicative stress in cancer cells to force mitotic catastrophe and cell death.

    Topoisomerase Gene Data

    Gene Species Gene Symbol Gene Accession No. Protein Accession No.
    Topoisomerase I Human TOP1 NM_003286 P11387
    Mouse Top1 NM_009408 Q04750
    Rat Top1 NM_022615 Q9WUL0
    Topoisomerase I (mitochondrial) Human TOP1MT NM_052963 Q969P6
    Mouse Top1mt NM_028404 NP_082680
    Rat Top1mt NM_001002798 Q6IM78
    Topoisomerase IIα Human TOP2A NM_001067 P11388
    Mouse Top2a NM_011623 Q01320
    Rat Top2a NM_022183 P41516
    Topoisomerase IIβ Human TOP2B NM_001068 Q02880
    Mouse Top2b NM_009409 Q64511
    Rat Top2b D14046 Q63177
    Topoisomerase IIIα Human TOP3A NM_004618 Q13472
    Mouse Top3a NM_009410 O70157
    Topoisomerase IIIβ Human TOP3B NM_003935 O95985
    Mouse Top3b NM_011624 Q9Z321