Table 1.
Steady-state constants for the decarboxylation of oxalate catalyzed by polyhistidine-tagged OxDC measured by membrane inlet mass spectrometry and by the formate dehydrogenase coupled assay. Reaction mixtures contained an initial concentration of 50 mM oxalate. Other buffer conditions were as described in Figure 2. Uncertainties are standard errors in the fit to the Michaelis-Menten expression.
Assay | Km (mM) | kcat (s−1) | kcat/Km (mM−1s−1) |
---|---|---|---|
MIMS | 4.0 ± 0.5 | 71 ± 2 | 18 ± 1 |
Dehydrogenase- coupled Endpoint Assay | 3.9 ± 0.4 | 44 ± 1 | 11 ± 1 |