硫之王：哺乳动物细胞产生并储存硫化合物以抗氧化

Mammalian cells produce and store a sulfur compound for antioxidant protection Richard Possemato1,2 Sulfur exists in a range of chemical states within biological systems, including thiols [cysteine and glutathione (GSH)], thioethers (methionine), thioesters (acyl–coenzyme A’s), disulfides (protein S–S covalent linkages), and iron-sulfur clusters. Oxidation or reduction of sulfur occurs in several of these states, linking these molecules to oxidative-stress management. Indeed, redox-active thiols in KEAP1 (Kelch-like ECH-associated protein 1) are a major cellular redox sensor, and biosynthetic regulation of the antioxidants GSH and thioredoxin leverage sulfur redox cycling to maintain redox homeostasis (1). Catenated sulfur species and hydropersulfides, such as CysSSnH and GSSnH (n ≥ 1), are gaining appreciation as radical-trapping antioxidants and nucleophiles with distinct properties (2–4). …