high-density lipoproteins definition of high-density lipoproteins in the Free Online Encyclopedia.

Lipoproteins

complexes of proteins and lipids. Lipoproteins occur in plants and animals as constituents of all biological membranes and lamellar structures (in the myelin sheath of nerves, in the chloroplasts of plants, in the receptor cells of the retina). They occur in free form in blood plasma, from which they were first isolated in 1929.

Lipoproteins are classified according to chemical structure and lipid-protein ratio. They are subdivided into four main classes according to sedimentation rate during centrifugal separation: (1) high-density lipoproteins (52 percent protein and 48 percent lipids, primarily phospholipids), (2) low-density lipoproteins (21 percent protein and 79 percent lipids, mainly cholesterol), (3) very low-density lipoproteins (9 percent protein and 91 percent lipids, mostly triglycerides), and (4) chylomicrons (1 percent protein and 99 percent triglycerides).

It is thought that lipoprotein structure is micellar (the protein bonded to the lipid-cholesterol complex owing to hydrophobic interaction) or analogous to that of molecular compounds of proteins and lipids (the phospholipid molecules located in flexures of the polypeptide chains of protein subunits). The study of lipoproteins is complicated by the instability of lipid-protein complexes and by difficulties encountered in their isolation in natural form.

REFERENCE

Finean, J. Biologicheskie ul’trastruktury. Moscow, 1970. (Translated from English.)

N. V. PROKAZOVA

Mentioned in	?		References in periodicals archive	?		Encyclopedia browser	?		Full browser	?
No references found	00 Hardcover RC692 Fielding (cardiovascular physiology, University of California-San Francisco) offers a detailed overview of the biological role of high-density lipoproteins (HDLs), summarizing current knowledge on HDL turnover, regulation, and physiology. High-density lipoproteins; from basic biology to clinical aspects by SciTech Book News Reverse cholesterol transport (RCT) is the process by which high-density lipoproteins (HDL) are able to extract excess cholesterol from blood vessel walls and deliver it back to the liver and gastrointestinal tract for disposal (Figure). Colesevelam, atherosclerosis, and reverse cholesterol transport by Toth, Peter P. / Journal of Applied Research It is characterized by a severe deficiency or absence of high-density lipoproteins in plasma. Tonsil with Tangier disease. (Pathology Clinic) by Thompson, Lester D.R. / Ear, Nose and Throat Journal	high-angle gun high-angle strafing high-aspect-ratio micromachining high-bay lighting high-bond bar high-bond mortar high-build coating high-burst ranging high-bush cranberry high-calcium lime high-capacity floppy high-capacity projectile high-carbon chromium high-carbon steel high-challenge fire hazard high-current rectifier high-current switch high-def video formats high-definition DVD high-definition formats high-definition television high-density concrete high-density disk high-density drive high-density lipoprotein high-density lipoproteins high-density overlay high-density plywood high-density polyethylene high-density server high-discharge mixer high-early-strength cement high-early-strength concrete high-efficiency particulate air filter High-Elastic State high-electron-mobility transistor high-energy astrophysics high-energy bond High-Energy Compounds high-energy electron diffraction high-energy environment high-energy fuel high-energy neutron-proton scattering high-energy particle high-energy physics High-Energy Physics, Institute of high-energy proton-proton scattering high-energy scattering high-energy-rate forging high-epithermal neutron range high-expansion alloy	High-Density Bipolar C High-Density Bipolar-3 zeros High-Density Black Area high-density CD-ROM high-density CD-ROM high-density CD-ROM High-Density cDNA Filter Analysis High-Density Complimentary Metal Oxide Semiconductor high-density concrete High-Density Data System High-Density Disk High-Density Disk high-density drive High-density DVD High-Density Epidermal Cells High-density fiberboard High-density fiberboard High-Density Field Directional Frequency & Ranging High-density high-delivery hosting High-Density Hispanic Area High-Density Inductively Coupled Plasma Chemical Vapor Deposition High-Density Information System High-density Instruction Set Computer HIgh-Density Integrated Circuit CArd High-Density Interconnect high-density lipoprotein high-density lipoprotein high-density lipoprotein High-Density Lipoprotein Cholesterol High-Density Lipoprotein Cholesterol high-density lipoproteins High-density liporotein High-Density Molecular Weight High-Density Multichip Interconnect high-density overlay High-Density Particle Agglutination test high-density plywood high-density polyethylene high-density polyethylene High-Density Polystyrene High-Density powder, Low-Velocity air High-Density Rack Mount High-Density Radiation-Resistant Microelectronics High-density server High-Density Station Interface High-Density Subscriber Line High-Density Turbidity Current High-Density Urethane high-dependency High-dimensional High-dimensional High-dimensional High-dimensional High-Dimensional Data Clustering high-discharge mixer high-discretion procedure High-Distance Interleaver High-Dose Atropine Treatment High-Dose Chemotherapy High-Dose Chemotherapy

Mentioned in

References in periodicals archive

Encyclopedia browser

Full browser

No references found

00 Hardcover RC692 Fielding (cardiovascular physiology, University of California-San Francisco) offers a detailed overview of the biological role of high-density lipoproteins (HDLs), summarizing current knowledge on HDL turnover, regulation, and physiology.

High-density lipoproteins; from basic biology to clinical aspects by SciTech Book News

Reverse cholesterol transport (RCT) is the process by which high-density lipoproteins (HDL) are able to extract excess cholesterol from blood vessel walls and deliver it back to the liver and gastrointestinal tract for disposal (Figure).

Colesevelam, atherosclerosis, and reverse cholesterol transport by Toth, Peter P. / Journal of Applied Research

It is characterized by a severe deficiency or absence of high-density lipoproteins in plasma.

Tonsil with Tangier disease. (Pathology Clinic) by Thompson, Lester D.R. / Ear, Nose and Throat Journal

high-angle gun

high-angle strafing

high-aspect-ratio micromachining