Amino Acid Metabolism 10/24/16 German TEST #3 Flashcards
What are the essential Amino Acids?
- Isoleucine
- Leucine
- Valine
- Phenylalanine
- Tryptophan
- Histidine
- Lysine
- Threonine
- Methionine
What are the non-essential amino acids?
- Alanine
- Glycine
- Proline
- Tyrosine
- Aspartic Acid
- Glutamic Acid
- Arginine
- Serine
- Cysteine
- Asparagine
- Glutamine
What are the four fates of dietary amino acids?
- Protein synthesis
- Energy production
- Biosynthesis
- Urea excretion
What are the three fates of dietary amino acids?
- Used for protein synthesis within cells
- Catabolized for energy within cells
- Transported to the liver and excreted
Where does most amino acid catabolism occur?
-Liver
What are four metabolically important amino acids?
- Glutamate
- Glutamine
- Aspartate
- Alanine
What does ammonia do to K+ uptake?
-Disrupt astrocyte K+ uptake
What does the high extracellular K+ levels do to GABA receptors?
Prevents GABA inhibition
How are amine groups stabilized in the body?
- Urea
- Uric acid
What are two common amino acid catabolism reactions?
- Transaminase reactions
- One-carbon transfers
What does PLP (pyridoxal phosphate) have to do with transaminase reactions?
- Common coenzyme
- Carrier of amino groups
What is an example of a transaminase reaction?
A-Ketoglutarate to Glutamate
How is intracelluar ammonia buffered?
By converting glutamate to gluatamine
What is the formula for ammonia?
NH3
Why do you convert glutamate to glutamine to transport in the blood?
Glutamine is non-toxic
What enzyme converts glutamate to glutamine?
Glutamine synthetase
How does alanine help transport ammonium to the liver?
Glucose-Alanine cycle
How is alanine made?
By an aminotransferase cycle with pyruvate to alanine from glutamate to A-ketoglutarate
When does the glucose alanine cycle occur?
-Anaerobic states
What other cycle does the glucose alanine cycle coincide with?
Cori Cycle
What does the urea cycle ultimately secrete?
Liver Nitrogen
How many steps are in the urea cycle?
4
What is a molecules that is absolutely necessary for the urea cycle to occur?
Ornithine
What is urea?
A stable amine-rich molecule
T/F
The urea cycle is ATP dependent
True
Where does the urea cycle require enzymes from?
The mitochondria and cytoplasm
What three amino acids are involved with taking amine groups to the mitochondria?
- Alanine
- Glutamine
- Glutamate
Once you have the amine group inside the mitochondria what two molecules are produced?
- Aspartate
- Carbamoyl phosphate
What molecule is used a precursor to make aspartate?
Oxaloacetate
What removes just the Ammonium from glutamate?
-Glutamate dehydrogenase
What makes carbamoyl phosphate?
- Bicarbonate
- ammonium
- ATP
What takes the amine group from carbamoyl phosphate in the mitochondria?
Ornithine
When ornithine takes the amine group from carbamoyl phosphate what does it become?
-Citrulline
What gives citrulline another amine group in the cytoplasm?
-Aspartate
When citrulline receives an amine group from aspartate what does it become?
-Argininosuccinate
What is a side product released from argininosuccinates conversion to arginine?
-Fumarate
What is released from the conversion of arginine to ornithine in the urea cycle?
-Urea
What are the two levels of urea cycle regulation?
- Increased synthesis of the enzymes involved in the urea cycle
- Allosteric N-acetylglutamate regulation
T/F
The citric acid cycle and urea cycle are not directly linked
False
They are linked to each other
How is the CAC and Urea cycle linked?
The aspartate-arginino-succinate shunt
What are glucogenic amino acids?
-Amino acids that can be converted into glucose
What are ketogenic amino acids?
-Amino acids that can be converted into ketone bodies
What are three important one carbon transfer reactions cofactors?
- Biotin
- Tetrahydrofolate
- S-Adenosylmethionine (These are vitamins)
What are six amino acids that are degraded to pyruvate?
- Tryptophan
- Alanine
- Cysteine
- Serine
- Glycine
- Threonine
What are seven amino acids that degrade to Acetyl-CoA?
- Tryptophan
- Lysine
- Phenylalanine
- Tyrosine
- Leucine
- Isoleucine
- Threonine
What are five amino acids that are degraded to A-Ketoglutarate?
- Glutamate
- Glutamine
- Proline
- Arginine
- Histidine
What are four amino acids that are degraded to succinyl-CoA?
- Methionine
- Isoleucine
- Valine
- Threonine
What are two amino acids that are degraded to oxaloacetate?
- Asparagine
- Aspartate
What two pathways can tryptophan enter?
- Pyruvate
- Acetyl CoA
What three pathways can threonine enter?
- Pyruvate
- Acetyl-CoA
- Succinyl CoA
What two pathways can Isoleucine enter?
- Succinyl-CoA
- Acetyl-CoA
What two pathways can Phenylalanine enter?
- Acetyl-CoA
- Fumarate
What two pathways can tyrosine enter?
- Fumarate
- Acetyl-CoA
