Table 1.

LigAB Steady-State Kinetic Parameters Measured with PCA and Analogous Substrates in Air-Saturated Buffer

substrate	$K_{\mathrm{m}}^{\text{app}}$ (μM)	$k_{\text{cat}}^{\text{app}}$ (s−1)	$k_{\text{cat}}^{\text{app}}∕K_{\mathrm{m}}^{\text{app}}$ (M−1 s−1)	partition ratioa	$j_{\text{inact}}^{\text{app}}$ (s−1)
PCA	51 ± 4	216 ± 3	4.26 × 106	~18000	0.012c
gallate	441 ± 55	53 ± 2	1.21 × 105	~2500	0.021b
3OMG	2319 ± 316	7.3 ± 0.5	3.13 × 103	~5600	0.0013c
DHBAm	3263 ± 327	104 ± 5	3.20 × 104	~3200	0.033d

^aEstimated from the $j_{\text{inact}}^{\text{app}}$ and $k_{\text{cat}}^{\text{app}}$ (eq 5).

^bCalculated from a fit of eq 4 to j_s values determined from the fitting of progress curves (eq 3) at different concentrations of gallate.

^cConcentration dependent inactivation was not observed for PCA or 3OMG. $j_{\text{inact}}^{\text{app}}$ was calculated as an average of the j_s values determined from the fitting of eq 3 to progress curves at different substrate concentrations.

^dConcentration dependent inactivation was observed for DHBAm; however, the behavior is inconsistent with eq 4 due to highly inactivating product inhibition. $j_{\text{inact}}^{\text{app}}$ was calculated from an average of the j_s values determined from the fitting of eq 3 to progress curves of reactions with 1000–5000 μM DHBAm.