TABLE 3.
Effects of divalent cations on Pel activitiesa
| Divalent cation | Enzyme activity (%) |
||
|---|---|---|---|
| Pel-22 | Pel-66 | Pel-90 | |
| None | 100 (5.53) | 100 (3.16) | 100 (4.72) |
| Ca2+ | 208.48 (0.28) | 237.16 (16.64) | 262.59 (24.52) |
| Fe2+ | 231.42 (1.91) | 94.58 (4.1) | 100.3 (0.30) |
| Cu2+ | 193.27 (1.46) | 99.84 (3.41) | 119.87 (12.51) |
| Zn2+ | 132.18 (2.6) | 1.9 (0.71) | 2.69 (0.98) |
| Mg2+ | 190.39 (16.62) | 77.22 (0.75) | 91.59 (3.86) |
| Mn2+ | 135.74 (4.6) | 15.96 (1.68) | 17.48 (2.14) |
| Ni2+ | 190.92 (7.31) | 68.71 (3.83) | 100.61 (15.95) |
| Ba2+ | 180.97 (13.76) | 62.17 (2.7) | 79.04 (7.88) |
| Se2+ | 157.52 (3.13) | 82.26 (13.81) | 89.92 (6.39) |
a
Activity under standard conditions (100 mM Tris-HCl, 1 g/liter PGA, and pH 7.5 or 8) without any added cation was used as a reference (100%). The influence of each divalent cation was determined by using the corresponding chloride or sulfate salt at 0.1 mM. Each result reported is the average of three independent experiments, and the standard deviations (±) are indicated in parentheses.