Low-temperature EPR spectra of ferricyt <i>c</i> treated with AA.

<p>(A) EPR spectra of (300 µM) ferricyt <i>c</i> after a 12-h incubation with (1.0–5.0 mM) AA. (B) Time-response ERP spectra of ferricyt <i>c</i> treated with (1.0 mM) AA for 30 min. Incubation conditions: 50 mM phosphate buffer, pH 7.4, at 37°C. (C) MCD spectra of ferricyt <i>c</i> in the presence of AA. The conditions are ferricyt <i>c</i> (40 µM) MCD spectrum before treatment with AA (thick line) and MCD ferricyt <i>c</i> spectrum after 12 h of (5.0 mM) AA treatment (thin line). (D) CD spectrum of ferricyt <i>c</i> treated with 5.0 mM AA. Incubation conditions: 50 mM phosphate buffer, pH 7.4, at 37°C.</p

EPR spin-trapping studies and computer simulation of the AA system in the presence and absence of ferricyt <i>c</i>, under aerobic conditions.

<p>EPR spectra of DMPO-radical adducts were obtained after a 4-min incubation of (15 mM) AA at 25°C with (150 µM) cyt <i>c</i> in 50 mM phosphate buffer (pH 7.4) with (400 mM) DMPO. (A) Experimental spectrum (trace a) and computer simulations (traces b-d) of the DMPO/AA system, (B) Experimental spectrum (trace a) and computer simulations of the DMPO/AA/cyt <i>c</i> system (traces b-e). Trace <i>c</i> in panels A and B represents the DMPO-<b>^•</b>OH adduct spectrum, and trace d can attributable to the DMPO-AA<b>^•</b> adduct. Trace e in panel B represents an unknown DMPO adduct. Instrumental conditions: microwave power, 20.2 mW; modulation amplitude, 1.0; time constant, 1.63 s; scan rate 0.1 G/s; and receiver gain, 1.12×106.</p

Proposed mechanism of AA oxidation catalyzed by iron and copper ions (Adapted from Dutra et al.[14]).

<p>Proposed mechanism of AA oxidation catalyzed by iron and copper ions (Adapted from Dutra et al.<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0057790#pone.0057790-Dutra1" target="_blank">[14]</a>).</p

EPR spin-trapping studies of the ferricyt <i>c</i>/AA system under aerobic conditions.

<p>EPR spectra of DMPO-radical adducts were obtained after a 4-min incubation of 15 mM AA at 25°C in 50 mM phosphate buffer (pH 7.4) with (25 mM) DMPO: (A) DMPO experiments, (B) DMPO in the presence of DMSO 30% v/v, (C) DMPO in the presence of ethanol 30% v/v. For all of the figures: (a) control with ferricyt <i>c</i> (150 µM); (b) AA (15mM); (c) AA (15 mM)+desferoxamine (100 µM); (d) ferricyt <i>c</i> (150 µM)+AA (15 mM); (e) system d+CuZnSOD (50 U/mL); (f) system d+catalase (15 µM) for Fig. 2A and 2C only. Instrumental conditions: microwave power, 20.2 mW; modulation amplitude, 1.0; time constant, 1.63 s; scan rate 0.1 G/s; and receiver gain, 1.12×106.</p

Oxygen uptake by AA in the presence of ferricyt <i>c</i>.

<p>Experimental conditions: (50 µM) ferricyt <i>c</i> in the presence or absence of (5.0 mM) AA in 50 mM phosphate buffer, pH 7.4, at 37°C for 30 min. Experiments were performed in the absence or presence of catalase (5.0 µM) or CuZnSOD (50 U/mL). Data are representative of five independent runs. *p<0.05 relative to the system containing only AA and #p<0.05 relative to the AA/ferricyt <i>c</i> system.</p