Figure 3.

CSE directs GSH biosynthesis upon cysteine starvation. (A) Total metabolite level represented as normalized peak areas at 4 days in 30 µM cysteine. (B) Schematic of ¹³C₃-serine metabolite flux toward GSH synthesis. (C) Isotopologues (normalized peak area) after ¹³C₃-serine tracing at 4 days in 30 µM cysteine (n = 1 with 3 technical replicates in (A) and (C), no statistical analysis). CBS, cystathionine β-synthase; SHMT, Serine hydroxymethyltransferase; CSE, cystathionine-γ-lyase; GCLC, Glutamate-cysteine ligase catalytic subunit; GSS, glutathione synthetase.