Description_x000D_ Application_x000D_ DNA gyrase from Escherichia coli has been used in a study to investigate a comparative proteomic approach to better define Deinococcus nucleoid specificities. DNA gyrase from Escherichia coli has also been used in a study to investigate the role of the DnaK-ClpB bichaperone system in DNA gyrase reactivation._x000D_ Biochem/physiol Actions_x000D_ DNA gyrase is supplied as an A2B2 holoenzyme. The molecular mass of subunit A is 97 kDa and that of subunit B is 90 kDa. It catalyzes the ATP-dependent introduction of negative supercoils into relaxed DNA. DNA gyrase has been successfully converted into a type II topoisomerase by mutagenesis experiments._x000D_ Can be used to supercoil plasmids._x000D_ Unit Definition_x000D_ One unit of gyrase activity will supercoil 0.5 micrograms of pBR-322 DNA in 30 minutes at 37 °C._x000D_ Other Notes_x000D_ Solution in 50% Glycerol containing Tris buffer, DTT and EDTA.