Chapter 25: Lipid Metabolism Suggested problems: 1, 4, 5, 6, 8, 9
Table 25-1 Energy Content of Food Constituents.
Page 910
Figure 25-1 Mechanism of interfacial activation of triacylglycerol lipase in complex with procolipase.
Page 910
Figure 25-2 Catalytic action of phospholipase A2.
Page 911
Figure 25-3a Substrate binding to phospholipase A2. (a) A hypothetical model of phospholipase A2 in complex with a micelle of lysophosphatidylethanolamine.
Page 911
Figure 25-3b Substrate binding to phospholipase A2. (b) Schematic diagram of a productive interaction between phospholipase A2 and a phospholipid contained in a micelle.
Page 911
Figure 25-4b Structure and mechanism of phospholipase A2. (b) The catalytic mechanism of phospholipase A2.
Page 912
Page 914
Figure 25-7 X-Ray structure of human serum albumin in complex with 7 molecules of palmitic acid.
Page 914
Figure 25-8 Franz Knoop’s classic experiment indicating that fatty acids are metabolically oxidized at their b-carbon atom.
Figure 25-9 Mechanism of fatty acid activation catalyzed by acyl-CoA synthetase.
Page 915
Page 915
Figure 25-10 Acylation of carnitine catalyzed by carnitine palmitoyltransferase.
Figure 25-11 Transport of fatty acids into the mitochondrion.
Page 916
Figure 25-12 The -oxidation pathway of fatty acyl-CoA.
Page 917
Figure 25-14 Metabolic conversions of hypoglycin A to yield a product that inactivates acyl-CoA dehydrogenase.
Page 918
Figure 25-15 Mechanism of action of -ketoacyl-CoA thiolase.
Page 919
Page 919
Figure 25-16 Structures of two common unsaturated fatty acids.
Figure 25-17 Problems in the oxidation of unsaturated fatty acids and their solutions.
Page 920
Figure 25-18 Conversion of propionyl-CoA to succinyl-CoA.
Page 922
Page 922
Figure 25-19 The propionyl-CoA carboxylase reaction.
Figure 25-20 The rearrangement catalyzed by methylmalonyl-CoA mutase.
Page 923
Figure 25-21 Structure of 5’-deoxyadenosylcobalamin (coenzyme B12).
Page 923
Figure 25-23 Proposed mechanism of methylmalonylCoA mutase.
Page 926
Figure 25-25 Ketogenesis: the enzymatic reactions forming acetoacetate from acetyl-CoA.
Page 929
Figure 25-28 A comparison of fatty acid oxidation and fatty acid biosynthesis.
Page 931
Page 931
Figure 25-29 The phosphopantetheine group in acyl-carrier protein (ACP) and in CoA.
Figure 25-30 Association of acetyl-CoA carboxylase protomers.
Page 932
Figure 25-31 Reaction cycle for the biosynthesis of fatty acids.
Page 933
Figure 25-32 The mechanism of carbon–carbon bond formation in fatty acid biosynthesis.
Page 934
Page 935
Figure 25-33 Schematic diagram of the order of the enzymatic activities along the polypeptide chain of a monomer of fatty acid synthase (FAS).
Figure 25-36 Transfer of acetyl-CoA from mitochondrion to cytosol via the tricarboxylate transport system.
Page 937
Figure 25-37 Mitochondrial fatty acid elongation.
Page 938
Page 938
Figure 25-38 The electron-transfer reactions mediated by the D9-fatty acylCoA desaturase complex.
Page 939
Figure 25-39 The reactions of triacylglycerol biosynthesis.
Figure 25-40 Sites of regulation of fatty acid metabolism.
Page 941
Figure 25-41 All of cholesterol’s carbon atoms are derived from acetate.
Page 942
Figure 25-42 Squalene. (a) Extended conformation. Each box contains one isoprene unit. (b) Folded in preparation for cyclization as predicted by Bloch and Woodward.
Page 943
Figure 25-43 The branched pathway of isoprenoid metabolism in mammalian cells.
Figure 25-57 LDL receptor-mediated endocytosis in mammalian cells.
Page 953
Figure 25-59 Control of plasma LDL production and uptake by liver LDL receptors. (a) Normal human subjects. (b) Familial hypercholesterolemia (FH).
Page 956
Figure 25-59c Control of plasma LDL production and uptake by liver LDL receptors. (c) Long-term high-cholesterol diet.
Page 956
Page 957
Figure 25-60 Competitive inhibitors of HMG-CoA reductase used for the treatment of hypercholesterolemia.
Figure 25-61 Simplified scheme of steroid biosynthesis.
Page 958
Figure 25-62 Structures of the major bile acids and their glycine and taurine conjugates.
Page 959
Table 25-2 Sphingolipid Storage Diseases.
Page 979
Figure 25-89 The breakdown of sphingolipids by lysosomal enzymes.
Page 978
Figure 25-90 Model for GM2-activator protein–stimulated hydrolysis of ganglioside GM2 by hexosaminidase A.
Page 978
Figure 25-91 Cytoplasmic membranous body in a neuron affected by Tay–Sachs disease.
Page 979