apolipoprotein


apolipoprotein
The protein component of any lipoprotein complexes that is a normal constituent of plasma chylomicrons, HDL, LDL, and VLDL in humans.
- a. A-I an a. found in HDL and chylomicrons. It is an activator of LCAT and a ligand for the HDL receptor. A deficiency of this a. has been associated with low HDL levels and with Tangier disease.
- a. A-II an a. found in HDL and chylomicrons. It stabilizes HDL.
- a. A-IV an a. secreted with chylomicrons and also found in HDL. It participates in the catabolism of chylomicrons and VLDL. It is also required for activation of lipoprotein lipase.
- a. B apolipoproteins found in chylomicrons, LDL, VLDL, and IDL. Elevated in the plasma of individuals with familial hyperlipoproteinemia.
- a. B-100 an a. found in LDL, VLDL, and IDL. The ligand for the LDL receptor; absent in certain types of abetalipoproteinemia.
- a. B-48 an a. found in chylomicrons and chylomicron remnants. Retained in intestine of individuals with chylomicron retention disease.
- a. C-I an a. found in VLDL and chylomicrons. It modulates the interaction of a. E with VLDL.
- a. C-II an a. found in VLDL, HDL, and chylomicrons; an activator of lipoprotein lipase; a deficiency will result in accumulation of chylomicrons and triacylglycerols.
- a. C-III an a. found in VLDL, HDL, and chylomicrons. It inhibits a number of lipases.
- a. D an a. found in HDL. It forms a complex with LCAT and appears to be involved in the transport of bilin.
- a. E an a. found in VLDL, HDL, chylomicrons, and chylomicron remnants. Elevated in individuals with type III hyperlipoproteinemia. It has an important role in cholesterol transport.

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apo·li·po·pro·tein .ap-ə-.lī-pō-'prō-.tēn, -.lip-ō-, -'prōt-ē-ən n any of the proteins that combine with a lipid to form a lipoprotein and that are now grouped into four classes designated A, B, C, and E and formerly into a fifth class D now considered part of A often followed by the letter designating the class or by the letter and a number expressed in Roman or Arabic numerals to indicate a specific member of the class <\apolipoprotein B is a major component of LDL>

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n.
any one of a family of proteins found in the various lipoprotein, which transport hydrophobic lipid molecules in the plasma. Apolipoproteins have a range of molecular weights and perform a variety of functions during the life cycle of the lipoproteins in which they are found. These include acting as ligands for the binding of enzymes (apolipoprotein B) and as cofactors for the action of other enzymes (apolipoproteins A and C).

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apo·lipo·pro·tein (ap″o-lip″o-proґtēn) any of the protein constituents of lipoproteins; grouped by function in four classes A, B, C, and E (the former apo D is now apo A-III).

Medical dictionary. 2011.

Look at other dictionaries:

  • Apolipoprotein E — (APOE) is an apoprotein found in the chylomicron that binds to a specific receptor on liver cells and peripheral cells. It is essential for the normal catabolism of triglyceride rich lipoprotein constituents.cite web | title = Entrez Gene: APOE… …   Wikipedia

  • Apolipoprotein D — Apolipoprotein D, also known as APOD, is a human gene.cite web | title = Entrez Gene: APOD apolipoprotein D| url = http://www.ncbi.nlm.nih.gov/sites/entrez?Db=gene Cmd=ShowDetailView TermToSearch=347| accessdate = ] PBB Summary section title =… …   Wikipedia

  • Apolipoprotein C3 — Apolipoprotein C III is a very low density lipoprotein (VLDL) protein. APOC3 inhibits lipoprotein lipase and hepatic lipase; it is thought to delay catabolism of triglyceride rich particles. The APOA1, APOC3 and APOA4 genes are closely linked in… …   Wikipedia

  • Apolipoprotein A1 — Apolipoprotein A I, also known as APOA1, is a human gene.The protein encoded by this gene is an apolipoprotein. It is the major protein component of high density lipoprotein (HDL) in plasma. The protein promotes cholesterol efflux from tissues to …   Wikipedia

  • Apolipoprotein B — (APOB) is the primary apolipoprotein of low density lipoproteins (LDL or bad cholesterol ), which is responsible for carrying cholesterol to tissues. While it is unclear exactly what functional role APOB plays in LDL, it is the primary… …   Wikipedia

  • Apolipoprotein E — Bändermodell der Aminosäuren 1 191 des Apolipoprotein E4 nach PDB  …   Deutsch Wikipedia

  • Apolipoprotein A1 — Zwei ApoA1 Moleküle (lila Bänder) im Komplex mit Cholesterin (orange Kalotten) und Phospholip …   Deutsch Wikipedia

  • Apolipoprotein H — (Apo H), previously known as (β2 glycoprotein I, beta 2 glycoprotein I), is a multifunctional apolipoprotein. One of its functions is to bind cardiolipin. When bound the structure of cardiolipin and Apo H both undergo large changes in… …   Wikipedia

  • Apolipoprotein — Als Apolipoproteine (Apo von griechisch άπό: Ab , Weg ) bezeichnet man den Proteinanteil der Lipoproteine (u. a. Chylomikronen, VLDL, LDL, IDL, HDL), der die wasserunlöslichen Lipide im Blut transportiert. Die Apolipoproteine bilden zusammen mit… …   Deutsch Wikipedia

  • Apolipoprotein — Apolipoproteins are proteins that bind to fats (lipids). They form lipoproteins, which transport dietary fats through the bloodstream. Dietary fats are digested in the intestine and carried to the liver. Fats are also synthesized in the liver… …   Wikipedia

  • Apolipoprotein C2 — protein Name=apolipoprotein C II caption= width= HGNCid=609 Symbol=APOC2 AltSymbols= EntrezGene=344 OMIM=608083 RefSeq=NM 000483 UniProt=P02655 PDB= ECnumber= Chromosome=19 Arm=q Band=13.2 LocusSupplementaryData=Apolipoprotein C2 is an… …   Wikipedia


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