Week 7 - Liver Function Test Flashcards
What enzyme is involved in the urea/amino acid pathway?
AST
What is Creatine Kinase (CK) used to detect?
heart attack
What creatine kinase?
a biomarker
What is a classic example of an isoenzyme?
LDH
What is an isoenzyme?
- catalyse same type of reaction
- genetically determined differences in AA sequences
- not modifications
- a species may contain several isoenzymes
What defines an isoenzyme?
the genes sequence
What are AST and ALT indicators of?
hepatocyte damage
What are AST and ALT involved in?
amino acid breakdown
What is Lactate Dehydrogenase (LDH) involved in?
The reversible conversion between pyruvate and lactate.
What is Alkaline Phosphatase?
bile ducts not hepatocyte cells
- links to the excretion of biles salts and bilirubin
What is GTI linked to?
Cirrhosis
- cell death in hepatocytes
How can we determine different enzymes?
- we can use relatively specific substrates
- we can use inhibitors
- antibodies
- electrophoresis
Isoelectric Point
a protein has a neutral charge zero charge
Prothrombin Time
- relates to blood coagulation
- measure the amount of time for it to coagulate
- links to liver function because the liver synthesises the precursor for thrombin prothrombin. - enzyme required in blood coagulation cascade
What is another factor that affects prothrombin time?
deficiency in vitamin k
because vitamin K is a required factor for some of the enzymes in the coagulation pathway.
Where is albumin synthesised?
in the liver
What is the half life of albumin?
roughly 20 days
Why can albumin be a good indicator for long term liver damage?
has a long half life of 20 days
What does albumin do?
it is the main transport protein in the blood and transports fatty acids during fasting and transports clinical drugs
Where is bilirubin formed?
in the spleen
What is bilirubin formed from the breakdown of?
the haem group
What is a characteristic of bilirubin?
is it a very hydrophobic compound
Where is bilirubin transported to?
to the liver bound to albumin
What is bilirubin converted to in the liver?
a glucoronide conjugate which is one of the enzymes in phase two of drug metabolism
- this facilitated the excretion of glucoronide
