FIGURE 4. In vitro phosphorylation of FCH and CH by CK. Incubations were performed at room temperature with 25 mU/mL CK over choline concentrations of 0.001–10 mmol/L. Each data point represents results as mean ± SD of 3 samples. Similar inhibition of FCH and CH phosphorylation at higher choline concentrations is indicative of competitive inhibition of FCH phosphorylation by choline.