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a nonlipid protein portion occurring in plasma lipoproteins; there are five families of apolipoproteins, grouped into four classes according to function, A, B, C, and E (the former apolipoprotein D has now been placed in class A). Apolipoproteins play a role in the transport of lipoproteins.
The protein component of any lipoprotein complexes that is a normal constituent of plasma chylomicrons, HDL, LDL, and VLDL in humans.
apolipoprotein/apo·lipo·pro·tein/ (ap″o-lip″o-pro´tēn) any of the protein constituents of lipoproteins, grouped by function in four classes, A, B, C, and E.
apolipoprotein(ăp′ə-lĭp′ō-prō′tēn′, -tē-ĭn, -lī′pō-)
Any of various proteins that bind to insoluble lipids to form the soluble lipoproteins, such as HDL and LDL, that transport triglycerides and cholesterol within the body.
Etymology: Gk, apo + lipos, fat, protos, first
the protein component of lipoprotein complexes. Apolipoproteins bind to specific enzymes or transport specific proteins and direct lipoproteins to their sites of metabolism. See also apolipoprotein test.
apolipoproteinAny of a family of small proteins on the surface of lipoprotein complexes, which bind to specific enzymes or transport proteins across cell membranes, which correspond to the protein moiety of lipoproteins. See HDL-cholesterol, Kringle domain.
The protein component of lipoprotein complexes that is a normal constituent of plasma chylomicrons, high-density lipoproteins, low-density lipoproteins, and very-low-density lipoproteins in humans.
apolipoproteinOne of a number of glycoproteins forming part of the surface of LIPOPROTEIN particles in the blood. Apolipoproteins are polar structures which provide structural stability to the lipoprotein and act as receptors that help to determine the fate of the particle. Some act as cofactors for enzymes involved in lipid and lipoprotein metabolism. The level of apolipoprotein-A is genetically induced and a high level is a strong risk factor for premature coronary heart disease. It is a feature of FAMILIAL HYPERCHOLESTEROLAEMIA. Apolipoprotein-B is the binding site of low-density lipoproteins (LDL) to cellular LDL receptors and is concerned in the movement of CHYLOMICRONS from the intestine. Apolipoprotein-C is present on chylomicrons, high-density lipoproteins and very low-density lipoproteins. Apolipoprotein-E genotyping has been used to predict the likelihood of ALZHEIMER'S DISEASE.
a protein moiety occurring in plasma lipoproteins; there are five families of apolipoproteins, designated A-E.