Gluconeogenesis Flashcards
What amino acids are ketogenic only?
Lysine and Leucine (Catabolized from Aceryl CoA)
Is Acetyl CoA glucogenic?
No, all carbons are oxidized as CO2
Which part of the fatty acid can be used for gluconeogenesis?
Glycerol
3 enzymes needed for gluconeogenesis?
PEP carboxykinase, fructose bis-phosphatase, glucose 6 phosphatase
Where does gluconeogenesis occur?
Cytosol in liver
How many ATP does it take for gluconeogenesis?
4 ATP, 2 GTP, 2 NADH
What is the net ATP from gluconeogenesis?
24-26 ATP depending on which shuttle is used
What organs cannot perform gluconeogenesis?
Muscle & brain
What is ubiquitin
Tags protein for degradation. 1-2% body proteins degraded daily
Name essential amino aicds
Threonine, Valine, Tryptophan, Isoleucine, Leucine, Lysine, Phenylalanine, Methionine
Young animals need histidine, arginine, glycine
What are branched chain amino acids?
Leucine, Isoleucine, Valine.
Make 1/3 of all skeletal muscle proteins
Why must endogenous proteins be degraded?
Abnormal proteins, nutrient sotrage, regulation of enzymes
Which enzymes are both keto and glucogenic?
Isoleucine, Tryptophan, Tyrosine, Threonine, Phenylalanine
WHere are branch chain amino acids broken down?
Muscle because liver lacks branched chain a-Keto Acid Dehydrogenase
Other AAs in liver
How are AAs broken down?
Transaminase
Transfer of nitrogen group
What does the transamination of an amino acid produce?
Glutamate (using a-KG) and keto acid
What is the major carbon source for gluconeogenesis?
Amino Acids
Amino acids with 2 and 3 carbons become
Pyruvate
Amino acids with 4 carbons become
OAA
Amino acids with 5 or more carbons become
a-KG
Why are BCAA critical for brain tissue?
Neurotransmitter synthesis
What is a symptom of liver disease?
Decreased clearance of aromatic amino aicds
What can occur during an imbalance of AAA to BCAA
Hepatoencephalopathy
AAA levels increase in brain
“False neurotransmitters”
How are stored amino acids used?
Muscle breaks down to release Glutamine and Alanine
Alanine becomes pyruvate using a-KG
This makes alanine most important amino acid substrate
Why can’t muscles make Glucose from G6P?
Muscles do not have G6Phosphotase
