survey of biochemistry glycogen
DESCRIPTION
SURVEY OF BIOCHEMISTRY Glycogen. 2 Ways To Generate Glucose. Glycogenolysis. Gluconeogenesis. Break down of glycogen. Synthesis of glucose from non-carb precursors. Glucose 1-Phosphate. Glucose. Pyruvate. Lactate. Glucose 6-Phosphate. Energetics of Reversing Glycolysis. - PowerPoint PPT PresentationTRANSCRIPT
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SURVEY OF BIOCHEMISTRY
Glycogen
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2 Ways To Generate Glucose
Glycogenolysis Gluconeogenesis
Break down of glycogen
Glucose Glucose1-Phosphate
Glucose 6-Phosphate
Synthesis of glucose fromnon-carb precursors
Lactate Pyruvate
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Energetics of Reversing Glycolysis
Glucose
Pyruvate
Hexokinase ∆G° = -17 kJ/mol
Phosphofructokinase ∆G° = -14 kJ/mol
PyruvateKinase ∆G° =
-31 kJ/mol
Reversing glycolysis is not energetically feasible!
Ref: Rodney Boyer Interactive Concepts in Biochemistry
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Pyruvate to Phosphoenolpyruvate
Dilemma:• Oxaloacetate can only be generated from pyruvate in the mitochondria
• Pyruvate gets synthesized initially in the cytosol
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PEP and Oxaloacetate Transport
Fig 16-20 does not show pyruvate!
Draw another viewof this process thatmay be more helpful
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Gluconeogenesis
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Energetics Revisited
∆G value comparisons
By what mechanisms
do these enzymes
work?
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Pyruvate Carboxylase Cofactor
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Enzyme-Cofactor Complex
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Pyruvate Carboxylase
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Pyruvate Carboxylase
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PEPCK Mechanism
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Ch. 16 Overview
• 16-1 Glycogen Breakdown (Fri)
• 16-2 Glycogen Synthesis (Wed)
• 16-3 Control of Glycogen Metabolism (Wed)
• 16-4 Gluconeogenesis (Mon)
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Enzymes in Glycogen Synthesis
• UDP-Glucose Pyrophosphorylase
• Glycogen Synthase
• Glycogen Branching Enzyme
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UDP-Glucose Pyrophosphorylase
UDP-GlucosePyrophosphorylaseactivates glucosyl
units
PPi
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Glycogen Synthase
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Glycogen Branching Enzyme
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Overview
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PRS
• Which of the following enzymes is involved in gluconeogenesis?
1. Pyruvate carboxylase2. Pyruvate kinase3. Phosphofructokinase4. Glycogen synthase
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PRS
• Which of the following is not a product of glycolysis?
1. Pyruvate2. Fructose 1,6-Bisphosphate3. Oxaloacetate4. Glucose 6-Phosphate
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PRS
• Which enzyme produces glucose 1-phosphate?
1. Hexokinase2. Glycogen Debranching Enzyme3. Glycoen Branching Enzyme4. Glycogen Phosphorylase