TABLE 2.

Specific activities of recombinant gyrase enzymes

Assayed subunit	Sp act (Ua/mg) at K+-glutamate concn of:
	0 mM	100 mM	250 mM	300 mM	700 mM	750 mM
S. aureus GyrAb	0		4.3 × 105			1.2 × 106
E. coli GyrAc	1 × 106	5 × 105d		NDe	2.5 × 105d
Chimera 7 GyrAc	7.9 × 105	4 × 105		3 × 105	2 × 105

^aU, unit; 1 unit of gyrase was defined as the amount required to produce half-maximal supercoiling of 0.5 μg of relaxed pBR322 plasmid DNA under the specified test conditions.

^bReconstituted with wild-type S. aureus GyrB.

^cReconstituted with wild-type E. coli GyrB.

^dThe specific activity of KL16 GyrA was not limited by the activity of the GyrB subunit at the different K⁺-glutamate concentrations tested.

^eND, not determined.