Pentose Phosphate Pathway

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Pentose Phosphate Pathway
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Alias

• Hexose Monophosphate Pathway
• Phosphogluconate Oxidative Pathway
• PPP

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Basic Training

• Purpose
• NOT ATP!!
• Generate Reducing Power
• Make Five-carbon sugars

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Where Does This Happen?

• Location
• Cytosol

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Mix These Together

• Reactants
• NADP
• Glucose-6-P
• Products
• NADPH (2 per Glucose-6-P)
• Ribose

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ATP

• What is it good for?
• Nothing as far as this pathway is concerned.
• No ATP made or used
• Guaranteed Test Question!!
• Friends Dont Let Friends

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Reducing Power

• NADPH
• Electron donor
• Reductive Biosynthesis

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The Main Event

• NADH v. NADPH
• NADH Important for ATP production.
• NADPH Important for reductive biosynthesis.

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Here a Sugar, There a Sugar

• Five Carbon Sugars
• Ribose.
• Used for many biological processes
• ATP, CoA, NAD, FAD, RNA, DNA.

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The Reactions

• The first half of the PPP.
• Oxidative
• Makes NADPH
• Irreversible
• Key enzyme
• Glucose-6-P dehydrogenase

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KEY!!
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The Reactions

• The second half of the PPP.
• Non-oxidative
• Reversible
• Produces Ribose
• The intermediates can reenter Glycolysis.
• NO KEY ENZYMES!!!

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Keep Your Friends Close

• NADPH
• Used in reductive biosynthesis to make fat,
  steroids, and cholesterol.
• Detoxification.
• WBC activity (Respiratory Burst).
• Free radical protection.

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Keep Your Friends Close

• Ribose
• Used to make
• ATP
• CoA
• NAD FAD
• RNA DNA

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And Your Enemies Closer.

• PPP/Glycolysis overlap
• Glucose-6-P
• Glyceraldehyde-3-P
• Fructose-6-P

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Regulation

• The Regulation of the PPP is determined by
  metabolic need.
• Are we making stuff or energy?

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Uppers

• Stimulants
• NADP
• Building Fat
• Building Cells
• Anything else?

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Downers

• Inhibitors
• NADPH
• Ribose
• ADP/AMP
• Anything else?

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Big Picture

• Regulation
• ATP
• Citrate
• Insulin (based on EC)
• Glucagon
• Etc.
• How do these affect the PPP?

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Many Hats

• Reductive Biosynthesis
• Cholesterol
• Fats
• Cellular membranes

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Many Hats

• Detoxification
• This process uses NADPH to change chemicals from
  water insoluble to water soluble, so that they
  may be excreted.
• Cytochrome P-450

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Many Hats

• WBC Activity
• This process uses NADPH to create free radicals
  (ROS) that are used to kill/destroy the antigens
  phagocytized by the WBC.
• Respiratory Burst.
• Creation of a reactive species to destroy
• non-self.

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Many Hats

• Free Radical Protection
• Antioxidants are compounds that inhibit
  oxidation.
• Antioxidant protection prevents propagation.
• A process in which a free radical is created in a
  tissue and reacts with other tissue molecules,
  spreading the damage.

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Recycling Antioxidants

• NADPH is used to return antioxidants to their
  original state after they have inhibited an
  oxidation reaction.
• This whole process protects our tissues from
  reactive chemicals that may oxidize or reduce the
  chemicals that make up our tissues.

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Bodys Most Wanted

• Superoxide
• O2
• Hydrogen Peroxide
• H2O2
• Hydroxyl
• OH

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Bad Boys, Bad Boys
Your Reacting Days Are Over!!

• Superoxide Dismutase
• O2 H2O2
• Catalase
• H2O2 H20 O2
• Glutathione Peroxidase
• H2O2 H2O

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Parting Gifts

• Location Cytosol
• ATP None used or produced
• NADPH
• Reductive Biosynthesis, WBC, Detoxification, Free
  Radical Protection
• Ribose DNA, RNA, FAD, NAD
• Glycolysis Remember Overlap