Fig. 4
From: Fatal systemic disorder caused by biallelic variants in FARSA
a Purification profiles from heparin chromatography and SDS–PAGE gels showing purified protein bands of each variant. Most of the variants displayed similar profiles as wild-type FARSA, while the R404C mutant FARSA was not copurified with FARSB, similar to the P347L mutant. b In vitro ATPase activity of each purified variant was measured with a malachite green phosphate assay. Each dataset was collected in triplicate at eight different concentrations of l-Phe. Three independent experiments were performed for each dataset. The activity of each mutant was expressed relative to the wild-type activity (100%). N.D. means no activity detected. The F256L, F277V, and E418D mutants showed wild-type-like activity (more than 90% of wild-type activity) at saturated Phe concentrations, but their activities were significantly reduced compared with wild-type activity at low Phe concentrations, as shown in the enlarged graph on the right