Figure 7
From: Quantification of folate metabolism using transient metabolic flux analysis
THF balance. (a) Reactions where a one-carbon unit is incorporated into (red) or released from (blue) folates. Abbreviations: thf, tetrahydrofolate; mlthf, 5,10-methylene-thf; fthf, 10-formyl-thf; met, methionine; dTMP, thymidylate. (b) Rate of one-carbon transfer from mlthf to methionine. (c) Backward rate of glycine cleavage. It could not be estimated in MDA-MB-468 because the glycine M+1 fraction was close to the detection limit. (d) Formate released by the cholesterol synthesis pathway. Abbreviations: 44mctr, 4,4-dimethyl-5-α-cholesta-8,14,24-trien-3β-ol; for, formate. (e) Purine isotope fractions in untreated (white boxes) and atorvastatin-treated (red boxes) MDA-MB-231 cells. (f) Difference between one-carbon production by SHMT and one-carbon consumption by purine synthesis. Bars represent the average and error bars the standard deviation over three replicates. The symbol *X denotes a difference between untreated and MTX-treated with a statistical significance less than 5 × 10−X.