Summary of metabolism lecture
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Metabolism involves three main processes: generating ATP as energy currency, producing reducing power in the form of NADH and NADPH, and synthesizing biomolecules from building blocks. ATP is generated through oxidation of fuels and drives reactions. Reducing power in the form of NADH and NADPH is also generated from fuel oxidation and is used for biosynthesis. Central pathways have both catabolic and anabolic roles to break down and synthesize molecules. Metabolic regulation occurs through allosteric regulation, covalent modification, controlling enzyme levels, compartmentalization, and organ specialization.
Summary of metabolism lecture
- 1. Summary of Metabolism By- Dr. Armaan SinghBy- Dr. Armaan Singh
- 2. Basic Strategies of Catabolic Metabolism • Generate ATP • Generate reducing power • Generate building blocks for biosynthesis
- 3. ATP • Universal currency of energy • High phosphoryl-transfer potential • ATP hydrolysis drives reactions by changing the equilibrium of coupled reactions by a factor of 108 • Generated from the oxidation of fuel molecules
- 4. Reducing Power • Oxidation of fuel molecules generates NADH for mitochondrial ETC • NADPH is generated for reducing power for biosynthetic processes • Pentose phosphate pathway is the major source of NADPH
- 5. Biomolecules • Large number of diverse macromolecules are synthesized from a small number of building blocks. • Carbon skeletons from generated from the oxidation of macromolecules provide the building blocks for biosynthetic pathways. • Central metabolic pathways have anabolic as well as catabolic roles.
- 7. Relationships between catabolic and anabolic processes • The pathway leading to the biosynthesis of a compound are distinct from the pathway leading to its breakdown • This separation ensure that the processes are thermodynamically favorable in both directions • Allows for reciprocal regulation
- 9. Themes in Metabolic Regulation • Allosteric regulation • Covalent modification • Control of enzyme levels • Compartmentalization • Metabolic specialization of organs
- 10. Allosteric regulation • Typically associated with enzymes that catalyze irreversible reactions • Allosteric regulators can cause feed back or feedforward regualtion • Allosteric regulators are often related to the energy state of the cell • This type of regulation allows for immediate response to changes in metabolic flux (milliseconds to seconds) • Functions at local level
- 11. Covalent Modification • Covalent modification of last step in signal transduction pathway • Allows pathway to be rapidly up or down regulated by small amounts of triggering signal (HORMONES) • Last longer than do allosteric regulation (seconds to minutes) • Functions at whole body level
- 12. Enzyme Levels • Amount of enzyme determines rates of activity • Regulation occurs at the level of gene expression • Transcription, translation • mRNA turnover, protein turnover • Can also occur in response to hormones • Longer term type of regulation
- 13. Compartmentalization •One way to allow reciprocal regulation of catabolic and anabolic processes
- 14. Specialization of Organs • Regulation in higher eukaryotes • Organs have different metabolic roles i.e. Liver = gluconeogenesis, Muscle = glycolysis • Metabolic specialization is the result of differential gene expression
- 15. Lots ATP G-6-P Low ATP Need skeltons
- 19. Starvation • Fuels change from glucose to fatty acids to ketone bodies