Lipoproteins

a good explaination about lipoproteins

1. lipoproteins SOBIA RAFIQ M.Phil . biochemistry

2. Introduction: Lipoproteins are basically a core full of fat and cholesterol, along with a lipid membrane that contains amphipathic proteins called Apo lipoproteins.

3. Types of lipoproteins:

4. Lipid and protein content of lip-proteins: Apolipoprotein B is the primary apolipoprotein of chylomicrons, VLDL, IDL, and LDL particles. While ApoA-1 is present in HDL.

5. FUNCTION OF CHYLOMICRONS AND VLDL: Chylomicrons and VLDL deliver TAG to cells in the body. triglyceride-rich. Chylomicrons are synthesized by enterocytes VLDL is synthesized in the liver . The function of these lipoproteins is to deliver energy-rich triacylglycerol (TAG) to cells in the body . TAG is stripped from both through the action of lipoprotein lipase, an enzyme that is found on the surface of endothelial cells. convert TAG to fatty acids and monoglycerides. Used by the body or stored.

6. Low density lipoproteins: As VLDL particles are stripped of triacylglycerol, These particles are remodeled at the liver and transformed into LDL . Cells take up cholesterol by receptor-mediated endocytosis. LDL binds to a specific LDL receptor and is internalized in an endocytic vesicle . Receptors are recycled to the cell surface, while cholesterol is further processed in the body.

7. Function of ldl: The function of LDL is to deliver cholesterol to cells, where it is used in membranes, or for the synthesis of steroid hormones .

8. High density lipo-proteins: Additionally , excess cholesterol from cells is brought back to the liver by HDL in a process known as reverse cholesterol transport . HDL is synthesized and secreted by the liver and small intestine. It travels in the circulation where it gathers cholesterol to form mature HDL, which then returns the cholesterol to the liver via various pathways.

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