1 / 77

METABOLIC BIOCHEMISTRY

METABOLIC BIOCHEMISTRY. Lecture 20 March 10, 2005 Summary and Review. Metabolism - The overall process by which living systems acquire and utilize free energy to carry out biological work - The process by which a variety of small molecules are assembled from a few

caleb-bauer
Download Presentation

METABOLIC BIOCHEMISTRY

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. METABOLIC BIOCHEMISTRY Lecture 20 March 10, 2005 Summary and Review

  2. Metabolism • - The overall process by which living systems acquire and utilize free energy to • carry out biological work • - The process by which a variety of small molecules are assembled from a few • precursors; the small molecules then serve as building blocks for • macromolecular structures • Metabolism can be organized into pathways: these pathways may overlap, • and branch, and even consist of circular paths • A pathway consists of consecutive enzymatic reactions: the reactants, • intermediates and products are called metabolites • - The flux through each pathway is regulated by a sophisticated set of • metabolic regulatory mechanisms: feedback inhibition, allosteric interactions, • covalent modification of proteins/enzymes, etc. • - Over a 40 year time span a human being consumes tons of nutrients and • imbibes 20,000 liters of water, yet remains more or less at steady state

  3. -Metabolic pathways are irreversible at certain key steps where a large negative • free energy change occurs • -There are catabolic pathways (e.g.glycolysis) and anabolic pathways (e.g. gluconeogenesis);these are necessarily different at key steps, but may share some steps • -In eukaryotic cells the various metabolic pathways are compartmentalized: • cytosol, mitochondria, peroxisomes, chloroplasts, etc. • -The compartments are defined by membranes; special transport mechanisms must • exist to regulate the flow of reactants and products in and out of a compartment • In some cases the flow is determined by a concentration gradient (diffusion), but stillrestricted by a specific transporter; • in other cases integral membrane proteins can act as pumps to pump metabolites • and ions against a concentration gradient; this requires an input of energy

  4. Why study metabolism and its regulation? 1. This is what scientists do: it is an intellectual challenge The final result is satisfying and even beautiful (although beauty is in the eye of the beholder) 2. It turns out to have enormous practical value in the maintenance of our good health a) a common sense approach to nutrition b) an intelligent response to false advertising in understanding “metabolic diseases” (inborn errors of metabolism) a) diagnosis b) possible treatments c) establishing a genetic basis d) genetic counselling and prenatal diagnosis 3. you can make a lot of money (drugs, inhibitors, etc.)

  5. POWER = WORK / TIME (Physics) TIME = MONEY (Business) KNOWLEDGE = POWER (Academia) WORK KNOWLEDGE = ______________ (1) MONEY Solving for money: WORK MONEY = _________________ KNOWLEDGE

  6. If the true essence of life is the accumulation of experience through generations, then one may perhaps suspect that the key problem in biology from the physicists point of view is how living matter manages to record and perpetuate the experience Max Delbruck Mitchell’s CHEMIOSMOTIC HYPOTHESIS is one of the giant achievements of 20th century science It can almost literally explain how solar energy can be converted into force and kinetic energy (e.g. muscular motion) or electrical signalling between the brain and our peripheral nervous system

  7. Fatty acids Glycogen Glyoxylate Cycle Glucose Acetyl-CoA PEP Krebs Cycle Calvin Cycle mevalonate CO2 Cholesterol etc. CO2 Urea Cycle Electron Transport OXPHOS Light Reactions

  8. KEGG Kyoto Encyclopedia of Genes and Genomes

  9. OMIM Online Mendelian Inheritance in Man

  10. glycolysis gluconeogenesis glucokinase phosphatase phosphofructokinase PFK-1 phosphatase PEP carboxykinase pyruvate kinase pyruvate carboxylase 4 ATP, 2 GTP, 2 NADH needed 2 ATPs produced

  11. MUSCLE LIVER

  12. b-oxidation of fatty acids: 1. Activation in cytosol to acyl-CoA 2. Transacylation to form acyl-carnitine 3. Import into mitochondria 4. Transacylation to acyl-CoA 5. Four steps in b-oxidation

  13. 1. in plants 2. long chain FA in animal cells

  14. Ketone bodies

  15. acetyl-CoA + acetoacetate lyase decarboxylase dehydrogenase acetone b-hydroxy-butyrate

  16. Oxidative phosphorylation in mitochondria

  17. [4Fe-4S] [2Fe-2S]

  18. x atractyloside

  19. x x x x cyanide malonate rotenone antimycin

  20. Photosynthesis in chloroplasts

  21. 5 C3 -P 3 C5 - P aldolase C3 + C3 C6* C6* C6 C6 + C3 C4 + C5 C4 + C3 C7* C7* C7 C7 + C3 C5 + C5’ phosphatase transketolase aldolase phosphatase transketolase

More Related