TABLE 3.
Enzymatic activities of ColH mutant enzymes
| Enzymea | % (± SD %) of wild-type ColH activityb |
|---|---|
| Wild type | 100 |
| N439A | 108.43 ± 6.99 |
| E446Q | 14.75 ± 0.99 |
| E446A | 13.72 ± 0.73 |
| E446D | 49.00 ± 1.87 |
| E447Q | 5.13 ± 0.07 |
| E447A | 0.70 ± 0.15 |
| E447D | 0.80 ± 0.11 |
| E451Q | 5.55 ± 0.55 |
| E451A | 5.40 ± 0.11 |
| E451D | 12.31 ± 0.44 |
a
The enzymes with E446A, E446D, E447A, E447D, E451A, and E451D mutations were purified from recombinant E. coli strains, while the rest of the mutant enzymes were from recombinant B. subtilis strains.
b
The relative enzyme activity was expressed as a percentage of the relevant recombinant wild-type ColH. Pz peptide-hydrolyzing activities of the wild-type ColH enzymes from the recombinant B. subtilis and E. coli strains were 1,238 ± 45 and 1,011 ± 34 (the mean ± standard deviation) U/mg of protein, respectively. The results are shown as means ± standard deviations of triplicate determinations.