TAILIEUCHUNG - Lecture Biochemistry (2/e): Chapter 25 - Reginald Garrett, Charles Grisham

The lipids found in biological systems are either hydrophobic (containing only nonpolar groups) or amphipathic (possessing both polar and nonpolar groups). The hydrophobic nature of lipid molecules allows membranes to act as effective barriers to more polar molecules. In this chapter, we discuss the chemical and physical properties of the various classes of lipid molecules. The following chapter considers membranes, whose properties depend intimately on their lipid constituents. | Chapter 25 Lipid Biosynthesis to accompany Biochemistry, 2/e by Reginald Garrett and Charles Grisham All rights reserved. Requests for permission to make copies of any part of the work should be mailed to: Permissions Department, Harcourt Brace & Company, 6277 Sea Harbor Drive, Orlando, Florida 32887-6777 1 Outline Fatty Acid Biosynthesis & Degradation Biosynthesis of Complex Lipids Eicosanoid Biosynthesis and Function Cholesterol Biosynthesis Transport via Lipoprotein Complexes Biosynthesis of Bile Acids Synthesis and Metabolism of Steroids 2 Fatty Acid Pathways The Biosynthesis and Degradation Pathways are Different As in cases of glycolysis/gluconeogenesis and glycogen synthesis/breakdown, fatty acid synthesis and degradation go by different routes There are four major differences between fatty acid breakdown and biosynthesis 3 The Differences Between fatty acid biosynthesis and breakdown Intermediates in synthesis are linked to -SH groups of acyl carrier proteins (as compared to -SH groups of CoA Synthesis in cytosol; breakdown in mitochondria Enzymes of synthesis are one polypeptide Biosynthesis uses NADPH/NADP+; breakdown uses NADH/NAD+ 4 Activation by Malonyl-CoA Acetate Units are Activated for Transfer in Fatty Acid Synthesis by Malonyl-CoA Fatty acids are built from 2-C units - acetyl-CoA Acetate units are activated for transfer by conversion to malonyl-CoA Decarboxylation of malonyl-CoA and reducing power of NADPH drive chain growth Chain grows to 16-carbons Other enzymes add double bonds and more Cs 5 Challenge: Ac-CoA in Cytosol What are the sources? Amino acid degradation produces cytosolic acetyl-CoA FA oxidation produces mitochondrial acetyl-CoA Glycolysis yields cytosolic pyruvate which is converted to acetyl-CoA in mitochondria Citrate-malate-pyruvate shuttle provides cytosolic acetate units and reducing equivalents for fatty acid synthesis 6 Acetyl-CoA Carboxylase The "ACC enzyme" commits acetate to fatty acid .

• Sinh học
• Lecture Biochemistry
• Biological phenomena
• Living systems
• Structure of cells
• Lipid Biosynthesis
• Fatty Acid Biosynthesis
• Principles of biochemistry
• Lecture Principles of biochemistry
• Biological systems
• Biochemical compounds
• Biological macromolecules
• Chemical principles
• Properties of water
• Hydrogen bonding
• Amino acids
• Amino acid structure
• Protein purification
• Cell extract
• Protein classification
• Protein 3 Dimensional structure
• Protein folding
• Protein 3 D structure
• 3 D structure
• Oxygen binding curve
• Enzyme kinetics
• Rate constants
• Catalytic Power
• Classes of enzymes
• Inhibitor kinetics
• Enzyme regulation
• Allosteric regulation
• Enzyme action
• Mechanisms of enzyme action
• Ions Cofactors
• Metal ion
• Nguyên lý hóa sinh
• Biotin cofactor
• Conformation of monosaccharides
• Carbohydrate classifications
• Oligo carbohydrate
• Polysaccharides carbohydrate
• Lipid subclasses
• Acyl lipids
• Fluid mosaic model
• membrane transporters
• Metabolism proceed
• Anaeorbic process
• Triose Phosphate Isomerase
• Regulation of glycolysis
• Control points in glycolysis
• Citric acid cycle
• TCA cycle
• Additional pathways
• Carbohydrate metabolism
• Electron transport
• Chemosmotic theory