Liver Physiology: Protein Synthesis in the Liver and the Urea cycle Flashcards
6 Examples of Plasma proteins synthesised in the liver?
Albumin
CRP
Hormone binding globulins
Apolipoproteins
Ferritin
Caeruloplasmin
Where is Albumin synthesised?
The liver
How much Albumin is produced by the liver each day? What charge is it?
10-15g
Negative charge
Two main functions of Albumin
Plasma oncotic pressure
Carrier protein
What 4 things does Albumin tranport?
Hormones
Vitamins
Electrolytes
Drugs
What are 6 Causes of Hypoalbuminaemia?
Inflammation
Liver disease
Renal disease
Burns/trauma
Sepsis
Malnutrition
What is the Main consequence of Hypoalbuminaemia?
Oedema
What is a waste product of the conversion of Amino acids into alpha-keto acids?
Ammonium
What two places does the urea cycle occur?
Mitochondria (first part) and Cytosol (second part)
What two reactions occur once NH3 has entered the Mitochondria in the Urea cycle? Enzymes?
- NH3+ HCO3 + 2ATP–>Carbamoyl phosphate
Carbamoyl phosphate synthase
2.Carbomoyl phosphate + Ornithine –> Citrulline
Ornithine transcarbamylase
Where is Citrulline transported to once produced?
Into the Cytosol via a transport protein
What are the three reactions that occur once citrulline has been transported out of the Mitochondria?
- Citrulline + Aspartate + ATP–> Arginino succinate (Enzyme= Arginino succinate synthase)
- Arginino succinate–> Arginine + fumarate ( Enzyme=Arginino succinate lyase)
- Arginine +H2O–> Ornithine+ Urea (Enzyme= Arginase)
How is the Citric acid cycle linked to The urea cycle in 4 steps?
1.Fumurate produced when Argininosuccinate is converted into Arginine
2.Fumurate converted into Oxaloactate
3.Accepts amine group from glutamate forming aspartate
4.Aspartate donates its amino group into urea cycle
