Transcript Gluconeogenesis and PPP

Chapter 14
Glycolysis, Gluconeogenesis, and the
Pentose Phosphate Pathway
Part 2: Gluconeogenesis and PPP
Gluconeogenesis and PPP Learning Goals.
Know:
1. Entry to gluconeogenesis.
2. Glycolysis backwards: which enzymes are at Eq
and those that are the drivers.
3. What makes some amino acids glucogenic.
4. Pentose Phosphate Pathway entry by glucose-6-P
and transaldolases, transketolases.
5. Why the PPP is a web pathway.
Gluconeogenesis Forms Sugars from Other Metabolites
Going Forwards and
Backwards
The Beginning of Gluconeogenesis
Pyruvate Carboxylase
PEP Carboxykinase
Pyruvate Actually Has Two Ways to PEP
The End of Gluconeogenesis
Gluconeogenesis Energetics
EOC Problem 21: overall energetics of Glycolysis and
Gluconeogenesis.
EOC Problem 22: Concept of a Futile Cycle.
Pentose Phosphate Pathway Beginning
+aromatic amino acids + His
NADPH and Oxygen Toxicity
SuperOxide
Dismutase
PPP Beginning from Glucose-6-Phosphate
Lactonase
6-Phosphogluconate DH
Phosphopentose Isomerase (not an Epimerase)
Ribose-5-Phosphate Epimerase
PPP the Web like Pathway Stuck
onto the Side of Glycolysis
PPP Transketolases transfer 2 Carbon units
PPP Transketolases transfer 2 Carbon units
PPP Transaldolases transfer 3 Carbon units
Another Transketolase
PPP Arranged to Oxidize Glucose (6 in and 5 out)
6 Glucose-6-P
Control of PPP by NADPH
PPP Functions:
1. Produce Ribose-5-P for Nucleotide Synthesis
2. Produce Ribose-5-P for His Synthesis
3. Produce Erythrose-4P for Trp, Tyr, Phe Synthesis
WYF
4. Can Completely Oxidize Glucose
5. Source of NADPH (Biosynthesis, Oxygen Killing
System)
6. Can be Rearranged to Calvin Cycle – Fix CO2
7. Other Specialized Reasons (Heterofermenters, etc.
mainly in prokaryotes)
Things to Know and Do Before Class
1. Entry to gluconeogenesis.
2. Glycolysis backwards: which enzymes are at Eq
and those that are the drivers.
3. What makes some amino acids glucogenic.
4. Pentose Phosphate Pathway entry by glucose-6-P
and transaldolases, transketolases.
5. Why the PPP is a web pathway.
6. EOC Problems: 21, 22, 25 – 27.