The NADPH Link between the Renin Angiotensin System and the Antioxidant Mechanisms in Dopaminergic Neurons Explain how Inactivity or absence of Glucose 6 phosphate dehydrogenase ; a rate limiting enzyme in the Pentose phosphate pathway could lead to oxidative stress.* Glucose metabolism begins with its transport into cells via GLUT transporters, where it is phosphorylated to glucose 6 phosphate (Glucose 6 P). This molecule can enter various pathways, including the pentose phosphate pathway or hexosamine biosynthesis. Pentose Phosphate Pathway: High Yield Biochemistry Notes Oncourse Pentose Phosphate Pathway Protects E. coli from Antibiotic Lethality bioRxiv 6.3: The Pentose Phosphate Pathway Biology LibreTexts