TABLE 1.
Concn (mM) | Divalent cation activity (pmol/mg/min)
|
|||
---|---|---|---|---|
MgCl2 | MnCl2 | ZnCl2 | CaCl2 | |
0 | 580 | 250 | 260 | 260 |
0.01 | 480 | 830 | 220 | 320 |
0.1 | 5,000 | 3,800 | 470 | 660 |
1.0 | 11,000 | 2,100 | 520 | 150 |
5.0 | 2,900 | 270 | 190 | 51 |
The recombinant enzyme was preincubated with Bio-Rex 70 (sodium form) on ice for 20 min. Resin was removed, and MgCl2, MnCl2, CaCl2, or ZnCl2 was added at the indicated concentrations. Assays were performed as described in Materials and Methods. Reactions were incubated at 37°C for 10 min, stopped by the addition of water saturated with NaCl, and extracted with butanol-saturated with water. An aliquot was then taken for liquid scintillation spectrometry.