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. Author manuscript; available in PMC: 2011 Mar 24.
Published in final edited form as: J Am Chem Soc. 2010 Mar 24;132(11):3914–3922. doi: 10.1021/ja910578y

Figure 2.

Figure 2

Substrate identity dictates ONOO--induced structural changes in FePPCOX-1. (a) Cyclooxygenase-coupled peroxidase activity measured in purified FePPCOX-1 (2 μg) and microsomal COX-1 (10.5 μg) following the immediate addition of arachidonic acid (AA; 100 μM) and eicosapentanoic acid (EPA; 100 μM) at pH 8. Results are monitored as ΔA611 during a 60 s interval. Data are averages ± SEM. *p < 0.0002 for EPA-activation relative to AA-activation. (b) CD spectra acquired in the far UV region at 25 °C compare the structure of FePPCOX-1 (0.21 mg/ml; solid black) to AA-bound FePPCOX-1 (dashed). The red CD spectrum was acquired following incubation of AA-bound FePPCOX-1 with ONOO- (250 μM). (c) CD spectra were acquired similarly to (b) but for EPA-bound FePPCOX-1.