TABLE 1.
Effect of metal ions on α-amylase activitya
| Metal ion | Mean relative activity (%) ± SD |
|
|---|---|---|
| 1 mM | 5 mM | |
| K+ (KCl) | 98.7 ± 3.0 | 104.4 ± 4.7 |
| Mg2+ (MgCl2) | 94.3 ± 2.0 | 92.5 ± 0.1 |
| Mn2+ (MnCl2) | 130.4 ± 2.7 | 118.6 ± 1.9 |
| Ba2+ (BaCl2) | 96.4 ± 1.0 | 101.6 ± 8.5 |
| Ca2+ (CaCl2) | 105.3 ± 3.2 | 78.0 ± 0.6 |
| Ni2+ (NiCl2) | 84.9 ± 1.7 | 33.3 ± 0.2 |
| Cu2+ (CuCl2) | 22.3 ± 2.4 | 1.1 ± 0.1 |
| Cr3+ (CrCl3) | 73.6 ± 0.6 | 12.5 ± 1.2 |
| Zn2+ (ZnCl2) | 7.1 ± 1.8 | 2.7 ± 0.2 |
| Fe3+ (FeCl3) | 85.5 ± 0.1 | 3.9 ± 1.3 |
a
Samples were preincubated with various metal ions (1 and 5 mM) for 10 min at 4°C, and the remaining activity was measured under standard assay conditions. Activity in the absence of any additives was taken as the 100% value. Mean values from three independent experiments are shown.