Overview Function generation of ATP from glucose via substrate-level phosphorylation (as opposed to oxidative phosphorylation) used by all cells login to view 7 more bullets only source of energy for RBCs generation of intermediates for other pathways 1,3-BPG login to view 5 more bullets Pathway in cytoplasm irreversible net reaction glucose + 2Pi + 2 ADP + 2 NAD+ → 2 pyruvate + 2 ATP + 2 NADH + 2H+ + 2 H2O Important enzymes hexokinase - converts glucose into glucose-6-phosphate allowing "trapping" inside cell distribution login to view 2 more bullets kinetics login to view 2 more bullets regulation login to view 1 more bullet glucokinase (hexokinase IV) distribution login to view 4 more bullets kinetics login to view 2 more bullets regulation login to view 2 more bullets phosphofructokinase-1 rate-limiting step inhibited by ATP, citrate stimulated by AMP, fructose-2,6-bisphosphate login to view 1 more bullet pyruvate kinase catalyzes substrate-level phosphorylation inhibited by ATP, alanine activated by fructose-1,6-bisphosphate Hormonal regulation fasting state ↑ glucagon → ↑ cAMP → ↑ protein kinase A → ↑ FBPase-2, ↓ PFK-2 fed state ↑ insulin → ↓ cAMP → ↓ protein kinase A → ↓ FBPase-2, ↑ PFK-2 Disorders of Glycolysis Pyruvate kinase deficiency AR (most commonly) pathophysiology ↓ ATP generation login to view 3 more bullets back up of glycolysis login to view 1 more bullet presentation chronic hemolysis ↓ O2 affinity for HbA login to view 1 more bullet no Heinz bodies login to view 1 more bullet