Table 1.

Comparison of Steady-State Kinetic Parameters Determined for Wild-Type Av MDO and Selected Variants for 3mpa Reactions

	wild type (20 °C)	H157N (37 °C)	Y159F (37 °C)
$k_{\text{cat}}\left({\text{s}}^{-1}\right)$	0.45 ± 0.06	0.092 ± 0.003	0.081 ± 0.001a
$K_{\text{M}}(\mu \text{M})$	13 ± 5	12 ± 2	9 ± 2
$k_{\text{cat}}/K_{\text{M}}\left({\text{M}}^{-1}{\text{s}}^{-1}\right)$	27000 ± 3000	7800 ± 590	9000 ± 2700
coupling (%)	98 ± 6 (7.5)b	46 ± 6 (7.5)b	60 ± 4 (7.5)b
$\log \left(k_{\text{cat}}\right)-\text{pH}$
$\text{p}{K}_{\text{a1}}$	7.8 ± 0.2	–	–
$\text{p}{K}_{\text{a}2}$	9.2 ± 0.1	9.6 ± 0.1	–
$\log \left(k_{\text{cat}}/K_{\text{M}}\right)-\text{pH}$
$\text{p}{K}_{\text{a}1}$	7.4 ± 0.2	–	–
$\text{p}{K}_{\text{a}2}$	9.1 ± 0.1	9.5 ± 0.1	–
fit to eq	2	3	$f(x)=mx+b$
refs	21, 22	this work	this work

^aY159F $\log \left(k_{\text{cat}}/K_{\text{M}}\right)$ – and $\log \left(k_{\text{cat}}\right)-\text{pH}$ data optimal at the lowest pH values measured (5.5 ± 0.1).

^bpH value at which the coupling efficiency Y159F log(k /K ) was measured.