TABLE 3.
Enzymatic activitya
| Peroxidase cosubstrates | Relative activity (% of catalase activity)b
|
|
|---|---|---|
| KatA | KatB | |
| H2O2 + dianisidine | 0.28 ± 0.02 | 0.058 ± 0.0004 |
| H2O2 + pyrogallol | 0.29 ± 0.05 | 0.36 ± 0.002 |
| H2O2 + NADH | 0.022 ± 0.001 | 0.022 ± 0.004 |
| H2O2 + NADPH | 0.023 ± 0.005 | 0.019 ± 0.002 |
a
Enzymatic activities of KatA and KatB were measured in periplasm or spheroplast extracts of E. coli strain UM383 katE katG containing pMMB207αB-Km14 katA or pMMB207αB katB (Table 1). The E. coli strains were grown overnight in LB broth with chloramphenicol.
b
Activities (in micromoles of H2O2 or peroxidase cosubstrate converted per minute per microliter of extract) are expressed relative to catalase activity, set at 100%. Where appropriate, corrections were made for absorbance changes in extracts of UM383 with the vector pMMB207αB-Km14 alone.