Metabolism

Chapter 15 Metabolism

Terms

  • catabolism

    • fuel → cellular energy

  • anabolism

    • require energy

  • amphibolic pathway

    • pathway that can be either catabolic or anabolic

  • oxidation-reduction reaction

    • electron transfer

  • group-transfer reaction

    • transfer of a functional group from one molecule to another

  • hydrolytic reaction

    • cleavage of bonds by the addition of water

  • cleavage of carbon bonds by means other than hydrolysis or oxidation

    • 2 substrates yielding one product or vice versa

    • when H2O or CO2 are a product, a double bond is formed

  • isomerixation reaction

    • rearrangement of atoms to form isomers

  • ligation reaction

    • formation of covalent bonds

Chapter 16 Glycolysis

Pathway

Regulation

  • glycolysis predominates when energy or glycolytic intermediates are needed

  • gluconeogenesis predominates when there is a surpluss of energy and glucose precursors

  • energy needed → AMP inhibits fructose 1,6-biphosphatase, stimulates phosphofructokinase

  • high ATP levels → ATP and citrate inhibit phosphofructokinase, decrease in AMP relieves fructose 1,6-biphosphatase inhibition

  • pyruvate kinase inhibited by allosteric effectors ATP and alanine

  • pyruvate carboxylase and phosphoenolpyruvate carboxykinase inhibited by ADP

  • pyruvate carboxylase activated by acetyl CoA

Chapter 17 Citric Acid Cycle

Pathway

Regulation

  • Pyruvate dehydrogenase kinase (PDK) phosphorylates (turns off) E1

  • Pyruvate dehydrogenase phosphatase (PDP) dephosphorylates E1

  • PDK and PDP associated with E2-E3-BP core complex

  • high NADH, acetyl CoA, and ATP activates PDK

  • high ADP and pyruvate inhibit PDK

  • Ca2+ stimulates PDP

Chapter 18 Oxidative Phosphorylation

Chapter 20 Pentose Phosphate Pathway

Chapter 21 Glycogen Metabolism

Chapter 22 Fatty Acid and Triacylglycerol Metabolism

Chapter 23 Protein Turnover and Amino Acid Catabolism

Essential Amino acids

  • Histidine

  • Isoleucine

  • Leucine

  • Lysine

  • Methionine

  • Phenylalanine

  • Threonine

  • Tryptophan

  • Valine

  1. serine → pyruvate + NH4+

  2. cysteine → pyruvate + H2S, SCN-, or SO3 2-

  3. glycine → serine → pyruvate + NH4+

  4. threonine → pyruvate

  5. alanine → pyruvate + glutamate

  6. tryptophan → alanine → pyruvate

  7. aspartate → oxaloacetate + glutamate (or fumarate → urea)

  8. asparagine → aspartate + NH4 → oxaloacetate + glutamate

  9. glutamine → glutamate → alpha-ketoglutarate

  10. proline → glutamate → alpha-ketoglutarate

  11. arginine → glutamate → alpha-ketoglutarate

  12. histidine → glutamate → alpha-ketoglutarate

  13. methionine → propionyl CoA → succinyl CoA

  14. isoleucine → propionyl CoA → succinyl CoA

  15. threonine → propionyl CoA → succinyl CoA

  16. valine → propionyl CoA → succinyl CoA

  17. leucine → acetyl CoA + acetoacetate

  18. tyrosine → fumarate + acetoacetate

  19. phenylalanine → tyrosine → fumarate + acetoacetate

  20. glutamate → alpha-ketoglutatarate

  21. lysine → acetyl CoA