Preparation of Acyl-CoA Standards.

One hundred micromolar stock solution for the standard acyl-CoA esters in Milli-Q water with 100 mM ammonium formate, pH 5.0, was made by measuring the absorbance at 260 nm (ε = 16,400 mM⁻1⋅cm⁻¹). To prepare standard curves, equal concentrations of standard acyl-CoAs of interest were mixed, creating a master mix, and we performed twofold serial dilutions in Milli-Q water with 100 mM ammonium formate, pH 5.0. d₃-Acetyl-CoA was used as the internal standard.