topoisomerase


Also found in: Dictionary, Encyclopedia, Wikipedia.
Related to topoisomerase: DNA gyrase

topoisomerase

 [to″po-i´so-mer-ās]
an enzyme involved in mobilization and replication of DNA during cell division.

to·po·i·so·mer·ase

(tō'pō-i-som'ĕr-ās),
A type of enzyme converting (isomerizing) one topologic version of DNA into another; acts by catalyzing the breakage and reformation of DNA phosphodiester linkages.
[topo- + isomerase]

topoisomerase

(tō′pō-ī-sŏm′ə-rās′, -rāz′)
n.
Either of two isomerase enzymes that alter the topology of DNA molecules by breaking and reconnecting coiled strands.

topoisomerase

[to′po-i′so-mer-ās]
an enzyme involved in mobilization and replication of DNA during cell division.

topoisomerase

an enzyme involved in DNA replication that introduces a single-strand nick in the DNA enabling it to swivel and thereby relieve the accumulated winding strain generated during unwinding of the double helix.
References in periodicals archive ?
DNA topoisomerases and their poisoning by anticancer and antibacterial drugs.
Topoisomerase II-alpha expression in different cell cycle phases in fresh human breast carcinomas.
Quinolones also inhibit the activities of topoisomerase IV, another type 2 topoisomerase that is composed of two subunits encoded by the parC and parE genes.
Evidence also suggests that the generation of ROS and the induction of topoisomerase Il-DNA complexes may play a role in curcumin-induced cancer cell death (Kuo et al.
sup][18] To the best of our knowledge, no report has elucidated the role of deoxyribonucleic acid (DNA) topoisomerase I inhibitors in cancer-initiating cells.
Suppressing that many genes across the board-even to a small extent-means a person who is exposed to a topoisomerase inhibitor during brain development could experience neurological effects equivalent to those seen in a person who gets ASD because of a single faulty gene.
The goal of this study was to determine the resistance mechanism to fluoroquinolones in Salmonella isolates and investigate the association of quinolone resistance with mutations in the genes encoding for DNA gyrase and topoisomerase IV of S.
Doxorubicin analogs that are less cardiotoxic (cause reduced in vivo chronic cardiotoxicity in rats and rabbits) are also less potent as poisons for topoisomerase 2[beta] (top2[beta]) and equally or more potent as poisons for topoisomerase 2a (top2[alpha]) compared to doxorubicin (DOX).
Two major classes of topoisomerase enzymes have been identified, type I and type II.
Irinotecan and Topotecan are semisynthetic analogue of natural alkaloid Camptothecin ,and currently are the most widely used camptothecin analogs in clinical experiments that targets topoisomerase I enzyme.
Topoisomerase II: Studies have found that tumors with higher levels of topoisomerase II (topo-II) were more responsive to anthracyclines, but the reverse was also true, where tumors with topo-II deletion also had a high response.