β-oxidation, fatty-acid synthesis, ketogenesis, cholesterol/isoprenoid biosynthesis.
Lipid Metabolism
Fatty-acid β-oxidation
Mitochondrial four-step cycle (oxidation/hydration/oxidation/thiolysis) removing 2-carbon units as acetyl-CoA, generating 1 FADH2 + 1 NADH…
Fatty acid synthesis
Cytoplasmic biosynthesis of palmitate from 8 acetyl-CoA via acetyl-CoA carboxylase (ACC) + fatty-acid synthase (FAS, a multifunctional…
Ketogenesis
Hepatic production of acetoacetate + β-hydroxybutyrate + acetone from acetyl-CoA during prolonged fasting, starvation, or uncontrolled…
Cholesterol biosynthesis
Multi-step pathway from acetyl-CoA to cholesterol (~30 enzymatic steps). Rate-limiting step: HMG-CoA reductase (target of statins).…
HMG-CoA reductase
ER-membrane enzyme catalysing HMG-CoA → mevalonate using 2 NADPH — committed/rate-limiting step of cholesterol biosynthesis. Inhibited by…
Mevalonate (MVA) pathway
Eukaryotic/archaeal isoprenoid biosynthesis: acetyl-CoA → HMG-CoA → mevalonate → IPP/DMAPP → farnesyl-PP → squalene → cholesterol +…
Phospholipid biosynthesis
ER-based assembly of glycerophospholipids via the CDP-diacylglycerol or Kennedy (CDP-choline) pathways. Produces PC, PE, PS, PI,…
Lipoprotein
Soluble particles transporting hydrophobic lipids in aqueous blood: chylomicrons, VLDL, LDL, HDL. Classes defined by density;…
Eicosanoid synthesis
Arachidonic acid → COX pathway (prostaglandins, thromboxanes) or LOX pathway (leukotrienes). Targets of NSAIDs (COX inhibitors) and…
Sphingolipid metabolism
Ceramide → sphingomyelin, glycosphingolipids (cerebrosides, gangliosides). Defects cause lysosomal storage diseases (Tay-Sachs, Gaucher,…