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. Author manuscript; available in PMC: 2017 Jul 18.
Published in final edited form as: Chem Res Toxicol. 2016 Jun 15;29(7):1098–1107. doi: 10.1021/acs.chemrestox.5b00528

Figure 4.

Figure 4

Tricine scavenges radicals from the reaction of DOPAL and NAL. (A) The upper EPR spectrum results from the incubation of 40 mM NAL and 400 µM DOPAL. Three species are present, a semiquinone radical (g = 2.004) and two nitroxide free radicals derived from tricine (radical-1, g1 = 2.006, aN1 = 14.7 G; radical–2, g2 = 2.006, aN2 = 14.7 G aH2 = 15.7 G;). A previous study on free radicals derived from tricine reports these same two nitroxide free radicals and, upon correction, have identical hyperfine splittings.33 Note that these authors made a minor error in determining hyperfine splittings. The lower spectrum shows that 40 mM NAL incubated without DOPAL produced no detectable free radicals. (B) When 0.1 mM DOPAL and 10 mM NAL are incubated in 50 mM tricine buffer pH 7.4 a decreased rate of loss of DOPAL is seen compared to DOPAL and NAL incubated in 50 mM Na2PO4 pH 7.4 at 1 h and (C) at 2 h (n = 3). %[Initial] calculated as individual sample concentration relative to t = 0 concentration. Significance was determined by one-way ANOVA with Neuman Keuls Multiple comparison post test * = p < 0.001.