Inhibition of the reverse SCS reaction by itaconate. Succinate but not itaconate at 10 mM concentrations is metabolized by pig heart SCS-GTP (SCS-G) (A) and recombinant SCS-ATP (SCS-A) (B). (C) Itaconate inhibits SCS-A at the indicated ratios using 50 mM succinate in all reactions. Summary bar plots represent mean rates of acyl-CoA formation at 225 to 235 nm. The corresponding UV scans for panels A and B are provided in supplemental Figure 7. Bars represent means and error bars = 1 standard deviation (n = 2-3 biological replicates). Panel A: Student t test P value = .0001. Panel C: one-way analysis of variance P value = .0022 with Bonferroni post hoc test P values = .026, .0022, and .15 (not significant [ns]) for control vs 1:200, control vs 1:50, and 1:200 vs 1:50, respectively.