Frontiers Cysteine Depletion, a Key Action to Challenge Cancer Cells to Ferroptotic Cell Death Figure 3 from Glutathione synthesis. Semantic Scholar Amino Acid Biosynthesis: Overview and Insights The Medical Biochemistry Page Glycine and N acetylcysteine (NAC) are amino acidbased nutrients that serve as precursors for glutathione, one of the body's most important intracellular antioxidants. Glutathione plays a central role in reducing oxidative stress, supporting