Biochemistry- Lipids & Lipoproteins Flashcards
Which cells synthesize TAGs?
hepatocytes, intestinal cells, adipose cells
Which cells build TAGs De-Novo?
hepatocytes and adipose cells
What is the method that the adipose tissue can absorb FFAs?
The FFAs are broken down by capillary lipoprotein lipase
What is the first step in TAG synthesis?
The addition of CoA with the Free FA via Fatty-Acyl CoA Synthetase
How is the Glycerol Backbone made in the intestinal cell?
It is not made; actually it is transported directly from the lumen after pancreatic lipase activity
How is the glycerol backbone made in the hepatocytes?
In the hepatocytes, glycerol comes from the G3P dehydrogenase that converts Glucose…..DHAP–> G3P.
Glycerol kinase converts the glycerol–> G3P
What are the levels of which energy storage depletes over time?
Glucose, glycogen, protein, TAGs last
What is the forming blocks for the chylomicron?
TAGs, apolipoproteins, other liquids
Where do these chylomicrons go?
Chylomicrons are released into the lymphatic system and enter the blood via the thoracic duct
What promotes TAG synthesis in the liver hepatocytes?
Excess carbohydrates in the diet
How are chylomicrons and VLDL broken down into FAs for Adipocyte TAG synthesis?
Chylomicrons and VLDL are broken down by capillary lipoprotein lipase into FFAs. These FAs are added to CoA with Fatty-Acyl CoA synthetase to create Fatty Acyl-CoA.
What enzyme is responsible for converting TAG–> DAG?
ATGL (Adipose triglyceride lipase)
What is the 2 enzyme that converts DAG–> MAG?
Hormone Sensitive Lipase (HSL) + Lipoprotein lipase (LPL)
What converts MAG–> Glycerol?
MAG lipase
What does perilipin enzyme do?
Perilipin enzyme inhibits the breakdown of Hormone-Sensitive Lipase (HSL) which converts DAG–>MAG.
How many Acetyl CoAs is needed to create cholesterol?
18 Acetyl CoAs
What is the role of ApoCII protein?
It actually activates capillary lipoprotein lipase
What is the role of ApoE protein? (livER)
ApoE facilitates the uptake into the liver
what is the role of ApoB protein? (LymBh)
ApoB48 allows for uptake into the lymphatic system
What is hyperlipoproteinemia I?
It is a defect in the ApoCII protein complex causing excess in chylomicrons & VLDL
Which lipoprotein has the highest phospholipid and protein concentrations?
HDL
What are the benefits of the HDL-C protein in terms of heart health?
Reverse transport mechanism where you can grab LDL lipoproteins from the bloodstream and allow it to migrate from the periphery and transport to the liver.
What is hyperlipidemia type II?
LDL receptor deficiency which increases the amount of cholesterol in the blood, LDLs in blood, VLDL in blood
