. Author manuscript; available in PMC: 2021 May 7.

Published in final edited form as: Biochemistry. 2019 Sep 9;58(38):3990–4002. doi: 10.1021/acs.biochem.9b00659

Table 2. Kinetic characterization of huCOX-2 homodimer mutations.

k_cat and K_M values were derived from three independent determinations (± S.E) using an oxygen electrode. AA was used as the substrate at concentrations between 2μM and 200μM. Values for the relative peroxidase (POX) activity represent the average of two measurements, followed by normalization to the rate of the POX activity of wild-type enzyme.

Homodimer Construct	k_cat (s⁻¹)	K_M (μM)	k_cat / K_M	Rel. POX Activity (%)

Native	38.9 ± 3.7	17.7 ± 1.9	2.2	100
R513H	42.1 ± 0.6	23.8 ± 2.3	1.8	92
L531A	0.6 ± 0.08	NA	NA	89
L531F	25.2 ± 1.0	20.2 ± 1.5	1.2	82
L531N	15.0 ± 0.6	41.2 ± 3.7	0.4	106
L531W	8.7 ± 1.0	NA	NA	37