FIGURE 3.

Definition of H₂O₂ production specific to mGPDH. a, effect of 1 mm malonate on the rate of H₂O₂ production in the presence of glycerol phosphate, 4 μm rotenone, 2 μm myxothiazol, 2.5 μm antimycin A, and 250 nm free calcium. The total rate of H₂O₂ production (black circles) was significantly inhibited by malonate above 0.017 mm glycerol phosphate (p < 0.001; two-way ANOVA with Bonferroni post-test). The malonate-insensitive rate was assumed to define mGPDH-specific H₂O₂ production (white circles). Data are means ± S.E. (error bars) (n = 3–8). Rot, rotenone; myx, myxothiazol; ant A, antimycin A. b, effect of calcium on the malonate-sensitive component (site II_F) of H₂O₂ production rates in skeletal muscle mitochondria for the condition described in a. The presence of 250 nm free calcium (black circles) significantly increased the H₂O₂ production rates versus the absence of added calcium (white circles) for all concentrations of glycerol phosphate between 0.07 and 1.7 mm (p < 0.001; two-way ANOVA with Bonferroni post-test). Data are means ± S.E. (n = 3–8). c, effect of calcium on the malonate-insensitive component (mGPDH-specific) of H₂O₂ production rates in skeletal muscle mitochondria for the condition described in a. The presence of 250 nm free calcium (black circles) significantly increased the H₂O₂ production rates versus the absence of added calcium (white circles) for all concentrations of glycerol phosphate between 0.07 and 1.7 mm (p < 0.001; two-way ANOVA with Bonferroni post-test). Data are means ± S.E. (n = 3–8).