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2
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
3
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
4
Pyruvate to Phosphoenolpyruvate
Dilemma:• Oxaloacetate can only be generated from pyruvate in the mitochondria
• Pyruvate gets synthesized initially in the cytosol
5
PEP and Oxaloacetate Transport
Fig 16-20 does not show pyruvate!
Draw another viewof this process thatmay be more helpful
13
Ch. 16 Overview
• 16-1 Glycogen Breakdown (Fri)
• 16-2 Glycogen Synthesis (Wed)
• 16-3 Control of Glycogen Metabolism (Wed)
• 16-4 Gluconeogenesis (Mon)
14
Enzymes in Glycogen Synthesis
• UDP-Glucose Pyrophosphorylase
• Glycogen Synthase
• Glycogen Branching Enzyme
19
PRS
• Which of the following enzymes is involved in gluconeogenesis?
1. Pyruvate carboxylase2. Pyruvate kinase3. Phosphofructokinase4. Glycogen synthase
20
PRS
• Which of the following is not a product of glycolysis?
1. Pyruvate2. Fructose 1,6-Bisphosphate3. Oxaloacetate4. Glucose 6-Phosphate