Sterols Flashcards
Why do you need cholesterol?
Steroid hormones
Cell membranes
Bile salts
Vitamin D
What is the starting material for cholesterol?
Acetyl CoA
What are the three stages for the synthesis of cholesterol?
- Formation of isopentenyl pyrophosphate
- Condensation of 6 molecules to form squalene
- Cyclisation
Where does each stage for the synthesis of cholesterol happen?
Stage 1 happens in the cytoplasm
Stage 2 & 3 happen on the endoplasmic reticulum
What are statins?
A medication developed to help with elevated levels of cholesterol
What are statins used to treat?
Hypercholesterolemia - high cholesterol
Atherosclerosis - build up of plaque in the arteries
What are the key intermediates involved in cholesterol synthesis?
Isopentenyl pyrophosphate
Squalene
Lanosterol
What is the regulatory enzyme involved in cholesterol synthesis?
HMG-CoA reductase
What is the structure of cholesterol?
Four ring structure
Classic sterol group and one alcohol group plus a fatty acid
How many carbon atoms does cholesterol contain?
27
Which proteins control mRNA synthesis and where are they located?
SCAP and SREBP
Located in ER
Why do statins have an affect on cholesterol biosynthesis?
Because they are competitive inhibitors of the regulatory enzyme
