(4.2) Lipoproteins

Chylomicrons

• The largest lipoproteins that arise in the intestine

• Transport triglycerides to adipose and muscle

• Cause of a “milky” layer on the top of the plasma that has been refrigerated overnight

Very low-density lipoprotein

• Produced in the liver

• High triglyceride content

• Transports triglycerides synthesized in the liver to adipose and muscle tissue

Low-density lipoproteins

• High in cholesterol content

• Arises from VLDL lipolysis

• Transports cholesterol to the liver for bile or to the tissues for structural components

• Increased _____ cholesterol is associated with an increased risk for atherosclerosis

High-density lipoproteins

• Smallest and most dense LP

• Formed in the liver and intestinal mucosa

• Binds excess cholesterol and transports it back to the liver

• Increased _____ cholesterol fraction is significant in reducing the risk of heart disease

Chylomicrons

Triglycerides: 80% to 95%

Protein: 1% to 2%

Cholesterol: 1% to 3%

Cholesteryl esters: 2% to 4%

Phospholipids: 3% to 6%

Very low-density lipoproteins

Triglycerides: 45% to 65%

Protein: 6% to 10%

Cholesterol: 4% to 8%

Cholesteryl esters: 16% to 22%

Phospholipids: 15% to 20%

Low-density lipoproteins

Triglycerides: 4 to 8%

Protein: 18% to 22%

Cholesterol: 6% to 8%

Cholesteryl esters: 45% to 50%

Phospholipids: 18 to 24%

High-density lipoproteins

Triglycerides: 2% to 7%

Protein: 45% to 55%

Cholesterol: 3% to 5%

Cholesteryl esters: 15% to 20%

Phospholipids: 26% to 32%

Lipoprotein(a)

Protein: 27%

Lipid: 65%

Cholesterol: 8%

Lipoprotein X

It is the abnormal LP found in patients with obstructive biliary disease.

Beta-VLDL

It is another abnormal LP, also called (floating BLP) or (IDL). It is absent in healthy individuals but accumulates in type III hyperlipoproteinemia.

Chylomicrons

Lipoprotein Diameter: > 70 nm

Density: < 0.95 g/mL

Major Lipids: 90% TGex

Electrophoretic Mobility: Origin

Protein Content: 1% to 2%

Very low-density lipoproteins

Lipoprotein Diameter: 26-70 nm

Density: 0.95-1.006 g/mL

Major Lipids: 65% TGend; 15% chol

Electrophoretic Mobility: Pre-beta

Protein Content: 8% to 10%

Low-density lipoproteins

Lipoprotein Diameter: 19-23 nm

Density: 1.019-1.063 g/mL

Major Lipids: 50% chol

Electrophoretic Mobility: Beta

Protein Content: 20%

High-density lipoprotein

Lipoprotein Diameter: 4-10 nm

Density: 1.063-1.21 g/mL

Major Lipids: 20% chol; 25% phos

Electrophoretic Mobility: Alpha

Protein Content: 50% to 55%