Free cholesterol carried by _
Cholesterol esters carried by _
- LDL
- HDL
Cholesterol biosynthesis very active in _
Occurs in _
- Liver, intestine, kidney
- All nucleated cells
RDS
HMG CoA reductase
HMGCoA > Mevalonate
Acetyl CoA > squalene…all reactions are _ and occur in the _
- Anaerobic
- Cytoplasm
Squalene > Cholesterol…all intermediates are _ and need _
- Hydrophobic
- SCP
In demethylation of lanosterol, how are they lost
C14 as formate
2 C4 as CO2
HMGCoA reductase:
Phosphorylated _
Dephos _
- Inactive
- Active
Storage of cholesterol into cholesterol ester via what enzyme?
Acyl Cholesterol Acyl Transferase(ACAT)
Cholesterol homeostasis maintained by what organ?
Liver
Unabsorbed cholesterol end up as _, excreted as _
- Neutral sterols(coprostanol, cholestanone)
- Cholestenol
Major excretory product of cholesterol is _
Bile acids
HDL has apoproteins (3)
- ApoD(recognizes cholesterol)
- ApoE
- ApoA(serum activator of Lecithin Cholesterol Acyl Transferase)
Most common bile acids are _ and _
Known as _
- Cholic(OH at 7, 12), Chenodeoxycholic(OH at 7)
- Primary bile acids
Primary bile acids are secreted from _ to _ as / conjugates
Enter liver via _
- Gall bladder, Small intestine, glycine/taurine
- Entero hepatic circulation
Bile acids not reabsorbed end up as _
Known as _
- Deoxy/lithocholic acids(deconjugated)
- Secondary bile acids
Bile acid formation(C24)
4 steps…
- Hydroxylation (7 and 7,12)
- Epimerization (B > @hydroxyl)
- Reduction of = in B ring
- Oxidation(O-ox for 1st C and 1 round of B-ox > propionyl CoA cleavage(3C))
Bile acid resins bind _
and prevent _.
This _ cholesterol levels.
- Primary bile acids
- Reabsorption
- Decreases
Bile acid resins bind _
and prevent _.
This _ cholesterol levels.
Example _
- Primary bile acids
- Reabsorption
- Decreases
- Cholestryamine(breaks bile acids down for excretion)
