ALAS2 inhibition by itaconyl-CoA. Kinetic progress curves (A) and Lineweaver-Burk plot (B) indicating competitive inhibition of ALAS2 with an inhibitory constant = 100 ± 20 μM (mean ± 1 standard deviation) for itaconyl-CoA. Michaelis constant = 10 ± 2 μM (mean ± 1 standard deviation) for succinyl-CoA. Discontinuous colorimetric assays were conducted for n = 3 biological replicates (separate protein preparations).