Processing Of Protein Week 5 Flashcards
What is tyrosine used for?
Tyrosine is in dopamine, noradrenalin and adrenaline.
What amino acid is in haem?
Glycine is in haem.
What amino acid is found in serotonin?
Tryptophan is found in serotonin.
What amino acid is found in histamine?
Histidine
What amino acids are used in creatine ?
Glycine and arginine are used in creatine.
What is nitrogen used for in the body?
Nitrogen is used for energy or energy storage compounds if not synthesis. However the amino acid groups must be removed and nitrogen secreted safely from the protein
There are 3 steps to ammonia disposal, what are they?
The 3 steps are transamination, deamination and urea synthesis.
What is transamination?
Transamination is the transfer of a into group to alpha-keto glutamate forming glutamate. This require pyridoxal phosphate and transaminase.
What is deamination?
Deamination is the release of ammonia from glutamate (mainly in liver). This reaction requires glutamate dehydrogenase. Uses NADP produces NADPH.
What is pyridoxal phosphate?
Pyridoxal phosphate is the active form of vitamin B6. It is required for the transamination and non essential synthesis of amino acids –> to make neurotransmitters, haem and for energy and lipid synthesis.
A lack of pyridoxine phosphate leads to what?
Lack of vitamin b6 leads to anaemia (no haem), neurological symptoms, and poor growth and immune response.
Where does the urea cycle take place?
The urea cycle takes place partially in mitochondria and partially in the cytosol.
What is the controlling step in the urea cycle?
Carbomoyl phosphate synthetase is the key controlling step. Carbomoyl phosphate is formed from ammonia and bicarbonate. Requires ATP.
How is carbomoyl phosphate synthase 1 activated?
Carbomoyl phosphate synthase 1 is activated by N-acetyl glutamate which is formed when glutamate levels are high. (Signalling high levels of protein catabolism).
How is the urea cycle activated?
By high amino acid levels.
What happens in the cytosol of the liver in the urea cycle?
In the cytosol a second amino acid is added from aspartate.
This forms arginine allowing for urea to be released.
What is Uric acid?
Uric acid is derived from purine nucleotides rather than protein. Excess Uric acid in the blood (hyperuricaemia) can lead to deposition of sodium urate crystals in the kidneys and in the joints (gout).
Why does hyperuricaemia occur?
Hyperuricaemia is due to over production of urate or poor excretion via the kidneys.
High purine foods (red meat, yeast) should be avoided
What happens to the carbon skeletons left after nitrogen disposal?
The carbon skeletons are fed into Krebs cycle (ATP synthesis), glucose synthesis through gluconeogenesis
Which amino acids can’t be made into glucose?
Lysine and Leucine are solely ketogenic so can only be made into acetyl CoA or ketone bodies.
What is gluconeogenesis?
Gluconeogensis is glucose synthesis from non carbon intermediates during fasting or exercise.
Where does gluconeogenesis mainly take place?
Gluconeogenesis mainly takes place in thy cytosol of liver and kidney.
How long do glycogen stores last?
Glycogen stores last about 18 hours
What are the 3 main sources used for gluconeogenesis?
- Keto acids from amino acids
- Lactate from anaerobic glycolysis
- Glycerol from triacylglycerol breakdown.
