Table 3. Effects of divalent metals, EDTA, and D-desthiobiotin on hNTAN1 activity.
hNTAN1 (20nM) was preincubated in 50mM Tris-HCl, 150mM NaCl, pH 7.5 at 4°C for 3 hr with either EDTA (1mM), D-desthiobiotin (3mM), or a divalent salt (1mM). Reactions were initiated by addition of the preincubated enzyme (1nM) to 100μM N1-AII in 50mM Tris-HCl, 150mM NaCl, pH 7.5 at 37°C. After 4 min, reactions were quenched and then analyzed by HPLC as described in “Experimental Procedures”.
| Effector | % Activity Remaining |
|---|---|
| MgCl2 | 100 |
| CaCl2 | 100 |
| CoCl2 | 58 ± 2.8 |
| MnSO4 | 40 ±14 |
| NiSO4 | 39 ± 4.2 |
| CuCl2 | 0 * |
| ZnSO4 | 0 |
| EDTA | 100 |
| D-desthiobiotin | 100 |
Area of the product peak was less than or equal to that observed in an HPLC trace of N1-AII only at the equivalent reaction conditions.