CH13

  1. Pentose phosphate pathway (PPP)
    • Provides route for metabolism of glucose
    • ATP is consumed/produced
    • production of reducing power in form of NADPH and ribose
    • Location: liver, rbc's, mammary glands, adipose tissue, adrenal cortex
    • site: cytosol
    • function: generate NADPH for biosynthetic rxns ex: fatty acid/cholesterol synthesis
    • production of 5 carbon
    • generates ribose 5 phosphate & NADPH for nucleotide biosynthesis. one can get either one, or both.
    • regulated by G6PD
  2. 2 Pentose Phosphate Pathways
    • 1. Irreversible oxidative.
    • 2. Reversible non-oxidative.
  3. Irreversable oxidative rxns
    • 3 rxns
    • convert G5P to Ribulose5P w/ release of Co2 and nadph
  4. PPP in RBC
    NADPH used to regenerate the antioxidant glutathione, which protects cells against damage. (keeps glutathione reduced)
  5. G6PD: glucose-6p-dehydrogenase
    • Nadp is it's coenzyme
    • Rate limiting enzyme
    • converts g6p to 6phos-glu-nolacetone. Final is (ribulose5p)
    • inhibited by NADPH
    • Ratio of NADPH/NADP is high which inhibits enzyme activity.
    • In enhanced activity, ratio decrease, and demand of NADPH goes up.
    • 2 nadph for biosynthesis & glutathion (GSH)
    • Insulin regulates G6PD, pathway increases in FED state.
  6. NADPH
    • high energy, used for reductive synthetic reaction.
    • competitive inhibitor of enzyme G6PD
  7. GSH
    Antioxidant, neutralizes the oxidant activity of H2O2.
  8. NADH
    tranfer electrons to electron transport chain to make ATP
  9. RIB5P
    6phos-glu-nolactone hydrolyzed by 6phos-glu-nolactone Hydrolase
Author
smartguy
ID
223800
Card Set
CH13
Description
Pentose Phosphate Pathway and NADPH
Updated