TABLE 1.
Effect of organic solvents and NaCl on the stability of pLac Gy . Residual activity was measured at 60°C in presence of 1 mM ABTS and 50 μM CuCl2 in 0.04 M Britton-Robinson buffer (pH 5.0) after pre-incubating the enzyme in the test condition for 6 h. The activity of the enzyme without pre-incubation measured at the pH 5.0 at 60°C was set at 100%. All experiments were conducted in triplicates and uncertainties represent standard deviations.
| Buffer/Organic solvent | Concentration (% v/v) | Residual activity (%) (pLac Gy ) |
| Britton-Robinson buffer | --------- | 100 ± 0.0 |
| Deionised water | --------- | 91.9 ± 1.8 |
| Methanol | 10 | 23.8 ± 2.1 |
| — | 30 | 7.1 ± 1.8 |
| — | 50 | 2.9 ± 1.2 |
| Ethanol | 10 | 25.6 ± 2.3 |
| — | 30 | 7.0 ± 2.7 |
| — | 50 | 3.8 ± 1.3 |
| Acetone | 10 | 23.0 ± 2.1 |
| — | 30 | 6.9 ± 1.9 |
| — | 50 | 2.8 ± 1.9 |
| Acetonitrile | 10 | 9.7 ± 1.8 |
| — | 30 | 7.5 ± 1.7 |
| — | 50 | 2.7 ± 1.1 |
| DMSO | 10 | 11.5 ± 1.6 |
| — | 30 | 3.3 ± 1.2 |
| — | 50 | 2.6 ± 1.0 |
| Salt | Concentration (mM) | Residual activity (%) (pLac Gy ) |
| NaCl | 100 | 76.7 ± 2.8 |
| — | 500 | 75.0 ± 2.7 |
| — | 1,000 | 65.6 ± 3.0 |