. Author manuscript; available in PMC: 2010 Dec 22.

Published in final edited form as: Biochemistry. 2009 Dec 22;48(50):11902–11911. doi: 10.1021/bi901600f

Table 1.

Effects of inhibitors on PGHS-2 cyclooxygenase activity^a.

Inhibitor	1st time point		2nd time point		COX site Occupancy^b
	(min)	COX activity (units/μg)	(min)	COX activity (units/μg)	(EI’/Et)
None	16	26.0	159	28.1	0
Nimesulide	23	4.9	192	5.0	0.81
Diclofenac	30	0.1	186	0.0	1
Flufenamate	59	16.7	182	17.0	0.38
Meclofenamate	48	3.4	177	0.1	1
Niflumate	44	9.4	172	9.5	0.65
Flurbiprofen	39	1.8	168	1.8	0.93
Indomethacin	23	25.0	163	20.1	~0.3

The holoenzyme (11 μM in 0.1 M KPi, pH 7.2, containing 0.1% Tween 20) was incubated on ice with 1.5 eq of inhibitor and aliquots were withdrawn at the two time points indicated for assay of cyclooxygenase activity. The concentration of inhibitor in the assay was 35 nM.

Calculated as (1 – f), where f is the fraction of control activity remaining at the second time point; assumes that I dissociates from EI during assay.