Table 4.

Kinetic parameters and ionization constants influencing the activity and of Pce catalyzed hydrolysis of NPPC at 25°C (I = 0.05)

Parameter	Wild type	H90A
kl (s−1)	7.8 ± 0.5a	4.6 ± 0.2a
kh (s−1)	26.5 ± 0.5a	0.6 ± 0.1a
Km,lim (mM)	2.2 ± 0.2b
pKEH2	7.3 ± 0.3c 7.1 ± 0.6b
pKEH	7.3 ± 0.3c 7.1 ± 0.4b
pKEH2S	5.5 ± 0.3a 5 ± 1b	5.7 ± 0.2a
pKEHS	8.12 ± 0.05a 8.9 ± 0.1c 8.6 ± 0.1b	8.03 ± 0.07a

^a From k_cat fit.

^b From K_m fit.

^c From catalytic efficiency fit: k_l, k_hK_m,lim were fixed at the values derived from the k_cat and K_m fits.