Fig. 6.

Metabolomic analysis reveals a role for BH₄in metabolism. sEnd.1 endothelial cells were transfected with Gch1-specific siRNA and compared to cells transfected with NS scrambled control siRNA. Cell lysates were harvested and underwent metabolomics analysis as outlined in the ‘Experimental Procedures’. A) Glycolysis (red) and TCA cycle (blue) metabolites were detected and quantification established by comparison with known standards. Succinate, fumarate, phosphoenolpyruvate and Fructose 1-,6-bisphosphate were significantly increased in response to Gch1-specific siRNA transfection, while isocitrate levels were sown to be markedly diminished compared to NS control cells. B) The impact of these changes in mitochondrial electron transport chain protein expression, glycolytic and TCA cycle metabolites, was to significantly decrease ATP/ADP ratio induced following knockdown of Gch1 by targeted siRNA, and the resulting BH₄ deficiency. n =3 (*, p<0.05) (**, p<0.01) (***, p<0.001).