MB - Amino Acid Metabolism Flashcards
Are excess amino acids stored or secreted?
No
What is the destination for amino acids? (3)
1) Protein Synthesis
2) Direct use/Minor modification
3) Breakdown and Redeployment
How are amino acids directly used?
Via Neurotransmitters and Hormones
What are amino acids broken down into?
- Carbon Skeleton –> Biosynthetic Pathways
- Ammonia –> Urea Cycle
What is transamination?
The transfer of an amino group from one molecule to another
What are most amino acids transaminated to?
Glutamate (from α-ketoglutarate)
What is deamination?
The removal of amino group from a molecule
(Glutamate –> α-ketoglutarate)
What is Urea Synthesis?
The production of Urea from ammonium ions?
What is the first step of the urea cycle?
Ammonium Ions –> Carbamoyl Phosphate
* Carbamoyl Phosphate Synthetase
What are the next 4 steps of the urea cycle?
1) Carbamoyl phosphate + Ornithine –> Citrulline
2) Citrulline + Aspartate + ATP –> Arginino-Succinate + AMP
3) Arginino-Succinate –> Arginine + Fumerate
4) Arginine + H2O –> Ornithine + Urea
Describe the structure of Urea
Carbonyl group attatched to 2 amino groups
* Small and Hydrophilic
Can Urea be made outside the liver?
No
Name 7 structures the carbon skeletons end up as
1) Pyruvate
2) Acetyl CoA
3) Acetoacetyl CoA
4) α-ketoglutarate
5) Succinyl CoA
6) Fumarate
7) Oxaloacetate
What does the destination of carbon skeletons depend on?
The starting amimo acid
Can sulphurous amino acids be used as an energy source?
No
Methionine –> Succinyl CoA
Cysteine –> Pyruvate
