Table 2.
Effects of different buffers, metal ions, and chemical reagents on the activity of ApuASK.
| Buffers, metal ions, and chemical reagents | Relative activity (%) |
|---|---|
| Buffers (100 mM, pH 7.5) | |
| Sodium phosphate | 47 ± 0.04 |
| Potassium phosphate | 100 ± 0.08 |
| Tris-HCl | 45 ± 0.05 |
| MOPS | 94 ± 0.02 |
| HEPES-NaOH | 15 ± 0.02 |
|
| |
| Metal ions (2 mM) | |
| None | 100 ± 0.02 |
| Na+ | 91 ± 0.01 |
| K+ | 128 ± 0.01 |
| Fe2+ | 108 ± 0.01 |
| Fe3+ | 196 ± 0.50 |
| Mg2+ | 114 ± 0.02 |
| Mn2+ | 182 ± 0.02 |
| Co2+ | 217 ± 0.03 |
| Cu2+ | 135 ± 0.03 |
| NH4+ | 83 ± 0.01 |
| Hg2+ | 16 ± 0.02 |
| Zn2+ | 70 ± 0.02 |
| Ni2+ | 154 ± 0.02 |
| Rb2+ | 14 ± 0.02 |
|
| |
| Chemical reagents | |
| None | 100 ± 0.02 |
| 5 mM EDTA | 3 ± 0.04 |
| 1 mM SDS | 33 ± 0.06 |
| 10 mM DTT | 45 ± 0.08 |
| 10 mM β-mercaptoethanol | 27 ± 0.05 |
| 3 mM Urea | 25 ± 0.06 |
| 1% (v/v) Tween-20 | 20 ± 0.09 |
| 1% (v/v) Triton X-100 | 15 ± 0.02 |
| 0.1% (w/v) α-CD | 19 ± 0.02 |
| 0.1% (w/v) β-CD | 6 ± 0.01 |
| 0.1% (w/v) γ-CD | 2 ± 0.01 |
Values are the mean ± standard error from triplicate analyses.