DNA topoisomerase (ATP-hydrolyzing)

DNA topo·isom·er·ase (ATP-hy·dro·lyz·ing) (to″po-i-somґər-ās hiґdro-li-zing) [EC 5.99.1.3] an enzyme of the isomerase class that catalyzes the ATP-dependent breakage, passage, and rejoining of both strands of a DNA helix simultaneously, altering the topology of the molecule by changing the linking number in steps of two. The enzyme removes and introduces superhelical turns and in prokaryotes is believed to be important in replication, transcription, recombination, and other processes. Called also type II topoisomerase and DNA gyrase.