Hydrogen Water vs. Glutathione Reductase (GR): Which Is Better? Evolved H2O Domains and Folds: Their Role in Protein Structure and Function Flashcards Quizlet The biochemical pathway that makes BH4 requires GTP as the substrate and three dedicated enzymes (GTP cyclohydrolase I, 6pyruvoyltetrahydropterin synthase, and sepiapterin reductase); the key redox cofactors used in the pathway and File:Glutathione Reductase and Peroxidase Graphic.jpg Wikimedia Commons A substitution in the glutathione reductase lowers electron leakage and inflammation in modern humans Science Advances Water Soluble Vitamins Springer Nature Link