Which of the following contains highest protein content?
Ans. b (HDL). (Ref. Harper, Biochemistry, 25th ed., 268)PROPERTIES OF PLASMA LIPOPROTEINS LipoproteinMajor lipidElectrophoretic mobilityMajor apoproteinsProtein content1ChylomicronTriglycerideNoneB-48, A-I, IV-2Very low density (VLDL)TriglyceridePre-betaB-100, E, C-I, II, III-3intermediateTriglyceride & density (IDL)cholestery! estersBetaB-100, E-4Low density (LDL)Cholesteryl estersBetaB-100-5High density (HDL)Phospholipids & cholesterolAlphaA-I, IIHighest LIPOPROTEINFUNCTIONSChylomicron- Delivers dietary triglycerides to peripheral tissues and dietary cholesterol to liver. (MH 2003) - Secreted by intestinal epithelial cells. - Levels are classically increased in lipoprotein lipase deficiency (AIIMS 99). - Excess causes pancreatitis, lipemia retinalis, and eruptive xanthomas.VLDLDelivers hepatic triglycerides to peripheral tissues. - Secreted by liver. - Excess causes pancreatitis.LDL- Delivers hepatic cholesterol to peripheral tissues. - Formed by lipoprotein lipase modification of VLDL in the peripheral tissue. - Taken up by target cells via receptor-mediated endocytosis. - Classically increased in familial hypercholesterolemia. - Most atherogenic (MH 2003)HDLMediates centripetal transport of cholesterol (reverse cholesterol transport) - Acts as a precursor for apoC and apoE (which are needed for chylomicron and VLDL metabolism). - Secreted from both liver and intestine. - Aptly known as "good cholesterol"
Triglycerides
HDL
LDL
VLDL
Lipids