Pentose Phosphate Pathway Reactions in Photosynthesizing Cells Hexose Monophosphate Pathway or Pentose Phosphate Pathway Animations PharmaXChange.info 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. Explain how Inactivity or absence of Glucose 6 phosphate dehydrogenase ; a rate limiting enzyme in the Pentose phosphate pathway could lead to oxidative stress.* The return of metabolism: biochemistry and physiology of the pentose phosphate pathway Stincone 2015 Biological Reviews Wiley Online Library Pentose Phosphate Pathway Definition and Mechanism