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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.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.
The protein component of any lipoprotein complexes that is a normal constituent of plasma chylomicrons, HDL, LDL, and VLDL in humans.
Farlex Partner Medical Dictionary © Farlex 2012
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.
The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.
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.
McGraw-Hill Concise Dictionary of Modern Medicine. © 2002 by The McGraw-Hill Companies, Inc.
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.
Medical Dictionary for the Health Professions and Nursing © Farlex 2012
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.
Collins Dictionary of Medicine © Robert M. Youngson 2004, 2005