Topoisomerase IV Assay Buffer (10X)

Topo IV Assay Buffer is supplied as a 10X Stock solution in two parts that must be mixed prior to use:
1. Incomplete Buffer A contains the following: 200mM HEPES-KOH [pH7.6], 500mM potassium glutamate, 50mM magnesium acetate, 50mM dithiothreitol, 250µg BSA/ml.
2. ATP Buffer B contains 100mM ATP in water.
These two buffers must be mixed to prepare a final 10X complete Topo IV Assay Buffer (A+B) as follows: add 0.1 volume of Buffer B to 1.0 volume Buffer A. Prepare only as much of the complete Topo IV Assay Buffer (A+B) as needed for each day or set of experiments. Note that this buffer should be kept on ice and used the same day, then discarded.