Lipids and Lipoproteins Flashcards
sources of TAGs
dietary (intestinal cells) de novo (hepatocytes and adipocytes)
what makes up a chylomicron
TAGs
apoproteins
other lipids (cholesterol, phospholipids, fat soluble vit)
how do chylomicrons enter the blood
chylomicrons are released into the lymphatic system and then enter blood via the thoracic duct
difference between chylomicrons and VLDLs
VLDL transports endogenous products (de novo)
chylomicrons transport exogenous products (dietary)
what is the backbone for fa synthesis
g3p (glycerol-3-phosphate)
capillary lipoprotein lipase is secreted by which cells
hepatocytes
what is lipoprotein lipase associated with
adipocytes (DAG breakdown to MAG)
what enzyme is used for TAG breakdown to DAG
HS lipase (hormone sensitive lipase)
what are the major enzymes for TAG breakdown
HSL (hormone sensitive lipase)
ATGL? (adipose triglyceride lipase)
LPL (lipoprotein lipase)
MAG Lipase
what modulates HSL and which is its active form
phosphorylation (phospho is active)
what is the function of perilipin
regulate lipolysis by controlling physical access to HSL
target of obesity treatment
what regulates perilipins
PKA (phospho is active; allows association with HSL)
5 major types of lipoproteins
chylomicrons VLDL LDL IDL HDL
structure of lipoproteins
outer shell:
- monolayer of phospholipids
- free cholesterol
- apolipoproteins
inner shell:
- hydrophobic TAGs
- cholesterol esters
which lipoprotein has the most TAGs and the least protein
chylomicrons
which lipoprotein has the least TAGs and the most protein
HDL
what is the function of apoB-48
facilitate transportation
what is the function of apoC-II
activate LPL
what is the function of apoE
facilitate uptake into liver
what is the function of apoA-I
activates enzyme that converts cholesterol into cholesterol ester
what do nascent chylomicrons need to become mature chylomicrons
apoC-II and apoE (supplied by HDL)
what is the function of apoB-100
bind to LDL receptors on target cells
what is the function of HDL-C
scavenges and removes LDL from periphery and takes it to the liver to be recycled and processed
what is Type I hyperlipoproteinemia (hyperchylomicronemia) caused by and what are the effects
inability to hydrolyze TAGs in chylomicrons and VLDLs
deficiency in apoC-II or defective LPL
effect: increased chylomicrons and TAGs
