Aerobic glycolysis, the citric acid cycle, and key glycolytic shunts. The diagram depicts glycolysis and ending with pyruvate and lactate. Intermediates are named and shown with space-filled models. The GLUT transporter and enzymes are shown with key rate-limiting steps highlighted in red. Reactions branching to the left are the pentose phosphate pathway, which produces ribose and NADPH; phosphofructokinase-fructose bisphosphatase (PFKFB), which produces fructose-2,6-bisphosphate, an allosteric activator of phosphofructokinase (PFKM); PFKM production of fructose-1,6-bisphosphate; and phophoglycerate dehydrogenase (PHGDH)-mediated production of serine. The last two allosterically activate pyruvate kinase M2 (PKM2). Pyruvate is shown converted to acetyl-CoA for further oxidation through the citric acid cycle depicted with intermediates forming in the mitochondrion. HK2, hexokinase 2; GPI, glucose-6-phosphate isomerase; ALDA, aldolase A; GAPDH, glyceraldehyde-3-phosphate dehydrogenase; PGK1, phosphoglycerate kinase 1; PGM, phosphoglycerate mutase; ENO1, enolase 1; LDHA, lactate dehydrogenase. Allosteric regulation is depicted by green dotted lines.