FIGURE 6.

Effect of fenamic acids on the heme oxidation states in huCOX-2. Visible spectra for Fe³⁺-protoporphyrin IX reconstituted huCOX-2 in the absence (A) and presence (B) of 10 μm tolfenamic acid. Spectra were recorded every 10 s. The red line denotes the resting state of the heme moiety before the addition of hydrogen peroxide. C, reconstituted huCOX-2 at a concentration of 3 μm monomer was reacted with 15 μm hydrogen peroxide for 45 s to generate compound II. After compound II was generated, fenamic acids were injected to a final concentration of 9 μm. The return of the heme moiety to the resting state was monitored by observing the increase in absorbance at 409 nm.