Glycolysis (EMP pathway), gluconeogenesis, fermentation, Warburg effect, pentose-phosphate bypass.
Glycolysis And Gluconeogenesis
Glycolysis (Embden-Meyerhof-Parnas)
Ten-step cytoplasmic pathway converting glucose → 2 pyruvate with net +2 ATP and +2 NADH. Universal across domains of life; hexokinase,…
Hexokinase / glucokinase
Enzyme committing glucose to metabolism: glucose + ATP → glucose-6-P + ADP. Isoforms: hexokinase (muscle, K_M ≈ 0.1 mM), glucokinase…
Phosphofructokinase-1 (PFK-1)
Committed step of glycolysis: F6P + ATP → F1,6-BP + ADP. Major regulatory enzyme: allosterically activated by AMP, F2,6-BP; inhibited by…
Pyruvate kinase
Glycolytic step 10: PEP + ADP → pyruvate + ATP (substrate-level phosphorylation). Allosterically activated by F1,6-BP (feed-forward);…
Gluconeogenesis
Reverse-glycolysis pathway generating glucose from pyruvate/lactate/glycerol/glucogenic AAs. Bypasses three irreversible glycolytic steps…
Cori cycle
Interorgan cycle: muscle glycolysis → lactate → liver gluconeogenesis → glucose → muscle. Shifts metabolic cost of ATP production to the…
Lactic fermentation
Anaerobic regeneration of NAD+ from NADH by lactate dehydrogenase: pyruvate + NADH → lactate + NAD+. Allows glycolysis to continue when O2…
Warburg effect
Aerobic glycolysis in rapidly proliferating cells (especially cancer): preference for lactate fermentation over oxidative phosphorylation…
Pentose phosphate pathway
Glucose-6-P oxidative branch producing NADPH (for biosynthesis/antioxidant defence) and ribose-5-P (nucleotide synthesis). Oxidative phase…
Fed/fasted glucose regulation
Insulin (fed) activates glycogen synthesis, glycolysis; glucagon (fasted) activates glycogenolysis, gluconeogenesis. Liver maintains blood…
Glycolytic ATP-yield stoichiometry framework
Net glycolytic stoichiometry: glucose + 2 NAD⁺ + 2 ADP + 2 Pᵢ → 2 pyruvate + 2 NADH + 2 ATP + 2 H₂O. Investment phase consumes 2 ATP…
Allosteric feedback regulation of PFK-1 framework
Phosphofructokinase-1 (PFK-1) is the canonical glycolytic flux-control point. Inhibited by ATP and citrate (energy/intermediate-rich…
EMP glycolysis (1930s)
Embden-Meyerhof-Parnas 1930s 10-step glucose -> 2 pyruvate; ATP yield +2; rate-limiting hexokinase + PFK1 + pyruvate-kinase; basis of…
Warburg effect (1924)
O Warburg 1924 (Nobel 1931) cancer cells preferentially ferment glucose -> lactate even with O2; targets HIF-1alpha + LDH; modern…
PFK1 allosteric (Lardy 1953)
Lardy 1953 PFK1 negative-feedback by ATP + citrate; positive by AMP + F-2,6-BP; rate-controlling step; cooperativity-Hill-coefficient ~3…
Cori cycle (1929)
C Cori-G Cori 1929 (Nobel 1947) lactate-glucose interconversion: muscle lactate -> liver gluconeogenesis -> glucose -> muscle; whole-body…
Hexokinase isozymes (Crane 1955)
Crane 1955 + Wilson 1995 4 hexokinase isozymes I/II/III/IV(=glucokinase); HK-IV liver Km~10 mM matches portal-glucose; HK-I/II ubiquitous…
Pentose phosphate pathway (Warburg 1933)
Warburg-Dickens 1933 + Horecker-Lipmann 1950s PPP: oxidative branch G6P -> R5P + 2 NADPH; non-oxidative transketolase/transaldolase; basis…
EMP pathway (Embden-Meyerhof 1933)
G Embden-O Meyerhof-J Parnas 1933 (Meyerhof Nobel 1922) classical 10-step EMP-glycolysis; foundation of bioenergetics.
Pasteur effect (1860)
L Pasteur 1860 fermentation O2-suppression; modern PFK-1 allosteric-regulation + Warburg-effect cancer + metabolomic-flux.
Warburg effect (1924)
O Warburg 1924 (Nobel 1931) aerobic-glycolysis cancer; modern PET-FDG imaging + targeted-LDHA + lactate-shuttle Faubert 2017.
Glucokinase (Cardenas 1972)
M Cardenas 1972 hexokinase-isozyme; modern GCK-MODY diabetes + glucose-sensor-pancreatic-β + glucokinase-activator drugs.
Cori cycle (1929)
C Cori-G Cori 1929 (Nobel 1947) muscle-liver lactate-cycle; modern PEPCK + fructose-1,6-bisphosphatase substrate-cycling regulation.
Krebs (1937)
H Krebs 1937 (Nobel 1953) citric-acid-cycle; modern flux-control-coefficient + metabolic-control-analysis Kacser-Burns 1973.