Kinetic parameters of the purified esterase pnbA-BS and its variant A400P^a.

Parameter	pnbA-BS	pnbA-BS A400P
K m (mM)	1.58 ± 0.13	0.94 ± 0.11
V max (U mg−1)	77.98 ± 0.35	2.03 ± 0.05
k cat (s−1)	69.93 ± 0.32	1.82 ± 0.04
k cat/Km (mM−1 s−1)	44.26 ± 0.20	1.94 ± 0.04

^aThe activity was determined using para-nitrobenzyl butyrate as a substrate in 100 mM PBS buffer (pH 9.0, 30 °C). In the assay mixture (200 μl), the assay was initiated by adding 3 μg of purified esterase pnbA-BS or its variant A400P. The substrate concentrations varied within the range from 0 to 50 mM. All activity assays were conducted in triplicate.