metabolism regulation 2

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metabolism regulation 2
2010-12-07 16:07:01

Test 4 ppt 5
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  1. reciprocal regulation of glycolysis/gluconeogeneis
    • F 2,6-BP is only in liver
    • Side product is not part of either pathway
  2. formation of F2,6-BP is controlled by...
    • phosphorylation
    • PFK2 and F2,6BPase reciprocally regulated by serine phosphorylation
  3. Metabolism after meal
    • high blood glucose (insulin high)
    • dephosphorylated PFK2 is active
    • Glycolysis stimulated
  4. Metabolism before a meal
    • low blood glucose (glucagon high)
    • phosphorylated PFK2-inactive
    • gluconeogenesis stimulated
  5. High glucose levels
    • increase F2,6-BP
    • increase glycolysis
  6. Starvation causes...
    • decrease in F2,6-BP
    • causes gluconeogenesis
  7. PFK regulated by cell's energy charge
    • Inhibited by high concentrations of ATP
    • ATP binding lowers PFK affinity for F6-P
    • AMP reverses inhibitory effect of ATP
  8. PFK and citrate
    • inhibited by citrate
    • high citrate concentrations signal high level of biosynthetic precursors
  9. 3 steps regulated in glycolysis
    • phosphofructokinase
    • hexokinase
    • pyruvate kinase
  10. Futile cycles
    • two metabolic pathways run simultaneously in opposite directions and have no overall effect other than wasting energy (net ATP hydrolysis)
    • generate heat
  11. F1,6BP and AMP
    F1,6BP not inhibited by AMP
  12. Honeybees (sooo relevant to dentistry!)
    • almost no F1,6-BP in flight muscles
    • cannot fly in cooler temps than 30 degrees C
  13. Hexokinase inhibited by...
    G6-P, which acccumulates in the cell as a result of the buildup of F6-P when PFK is inhibited
  14. Alanine inhibts or stimulates pyruvate kinase?
    • inhibits
    • sense levels of biosynthetic precursors
  15. Pyruvate Kinase in low blood sugar
    phosphorylated, less active
  16. Under Anaerobic conditions in the muscle...
    • pyruvate and NADH accumulate
    • NAD+ must be regenerated for glycolysis to continue
    • Cori Cycle
  17. PPP
    ribose phosphate also produced
  18. PPP and glycolysis linked by
    transketolase/transaldolase reactions
  19. PPP oxidative branch
    • G6-P dehydrogenase reaction
    • 2 NADPH produced
  20. Important enzymes in non-oxidative branch of PPP
    • Transketolase
    • Transaldolase
  21. Transketolase
    • 2 carbon unit transfer
    • Contains thiamine pyrophosphate (TPP)
    • C5+C5 <-> C3+C7
    • C5+C4 <-> C3+C6
  22. Transaldolase
    • 3 carbon unit transfer
    • C7+C3 <-> C4+C6
  23. Most importatnt regulatory factor of PPP
    • level of NADP+
    • tightly coupled to its utilization
  24. Ratio of NADP+/NADPH
  25. Ratio of NAD+/NADH
  26. Control of non-oxidative branch of PPP
    availability of substrates
  27. RBCs get ATP from...
    glycolysis only!
  28. RBCs produce 2,3-BPG from...
  29. in RBCs, NADPH used to
    regenerate reduced glutathione needed to protect against ROS
  30. what can produce free radical species?
    O2- and H2O2
  31. G6-P Dehydrogenase Deficiency
    • Can be caused by decreased production of enzyme, decreased catalytic activity, decreased enzyme stability
    • exposure to anti-malarial drugs results in incrased cellular production of superoxide and hydrogen peroxide
  32. Pyruvate Kinase Deficiency
    • ATP from glycolysis used for maintenance of RBC shape and Na/K gradients
    • ATP levels low in RBCs
    • spherical erythrocytes instead of normal bi-concave disc shaped cells
  33. Adenylate system
    ADP must be available for glycolysis, citric acid cycle, and Ox/Phos to proceed
  34. NAD+ required for...
    • glycolysis
    • pyruvate dehydrogenase
    • Citric acid cycle
    • beta-oxidation
    • amino acid deamination
  35. FAD required for
    • Citric acid cycle
    • beta oxidation
  36. CoA required for
    • pyruvate dehydrogenase
    • alpha-ketogluterate dehydrogenase
    • beta-oxidation
    • branched chain ketoacid dehydrogenase