In hypoxic conditions there is inhibition of phosphofructokinase 1 (PFK1, enzyme responsible for the conversion of fructose-6-phosphate to fructose-1,6-bisphosphate-, the first irreversible reaction unique to the glycolytic pathway), which results in O-GlcNAcylation at Ser529 by OGT (O-linked N-acetylglucosamine transferase), redirecting the flux of glucose from glycolysis through the PPP and thereby conferring a proliferative advantage to cancer cells [93]. The gene discussed is PFKM; the disease is cancer.