GCLC and neoplasm: Similarly, the mRNA levels for Gclc and Gclm, two other Nrf2-transcriptional targets encoding the catalytic and the modifier subunits, respectively, of glutamate-cysteine ligase, the enzyme catalyzing the rate-limiting step in the biosynthesis of glutathione (GSH), were similar in tumor compared to peri-tumoral tissue, although both were higher in tissues from Keap1-KD compared to WT mice (Fig. 3f, g), as expected31.