Glycolysis:

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Glycolysis

• Death To Sugar

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Carbohydrate Facts

• We eat all types of sugars, but we can only
  process D conformation sugars. All people lack
  the enzyme to break down cellulose (because of
  its Beta 1-4 bond) and many lack enzymes to
  breakdown sugars such as lactose.
• We store sugar by converting it into glycogen,
  which is stored in the muscle (400g) and liver
  (100g).
• Carbohydrates are the exclusive fuel source for
  the brain, lungs, and liver.

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The Essentials

• Location
• Cytosol (rule of 10)
• Purpose
• Make ATP
• Make precursors to the aerobic system

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Six of one

• The first half of Glycolysis.
• Goal
• To change glucose into an energy rich sugar.
• This costs 2 ATP.
• Where does this energy come from?

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Half-dozen of the other.

• Glycolysis better half
• Goal
• Breakdown the new energy-rich sugar to make ATP.
• This yields 4 ATP per glucose. (Remember we used
  2 in 1st half, so 4 2 2 ATP net)

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GlycolysisCaught in the Act!
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The Usual Suspects

• Reactants
• Glucose
• ADP/AMP
• Products
• ATP (2 net)
• Pyruvate

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The Usual Suspects

• Key enzymes
• Hexokinase (Uses ATP)
• PFK (Uses ATP)
• Phosphoglycerate Kinase (Makes ATP)
• Pyruvate Kinase (Makes ATP)
• Lactate Dehydrogenase

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PFK Rules!

• PFK
• The rate limiting enzyme of Glycolysis.
• Guaranteed Test Question!!!
• Why not Hexokinase?
• THE BIG PICTURE!

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PFK
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Regulation of Glycolysis

• Stimulants
• Low EC
• Glucose
• Fructose 1,6 Bisphosphate
• Remember, reactants and things that stimulate
  enzymes of a pathway stimulate that pathway
  (general rule).

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Regulation of Glycolysis

• Inhibitors
• High EC
• Pyruvate
• Lactate
• Alanine
• Low pH
• Citrate
• NADH
• Remember, products and things that inhibit
  enzymes of a pathway inhibit that pathway.

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A Word on Hormones

• Insulin
• Insulin is released when blood glucose is high.
• It moves glucose from the blood into the cell.
• This lowers blood glucose, and raises cellular
  glucose.

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A Word on Hormones

• Glucagon
• Glucagon is released when blood glucose is low.
• It moves glucose from the cell into the blood.
• This raises blood glucose, and lowers cellular
  glucose.

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More Hormones

• Insulin
• Will this stimulate or inhibit glycolysis?
• Glucagon
• Will this stimulate or inhibit glycolysis?

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Is this really the end?

• If pyruvate is the end product of Glycolysis, why
  is lactate so important?
• The conversion of pyruvate to lactate allows for
  the temporary overrunning of Glycolysis.
• How Why?
• Remember the BIG PICTURE!