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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.


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


References in periodicals archive ?
The effect of 8 weeks of aerobic training on serum lipoproteins in non-athletic girls", European Journal of Experimental Biology, 4(1): 358-360.
14] ApoE decreased with hydrocortisone, either as a result of less hepatic secretion or increased catabolism of apoE-containing lipoproteins, but lower production of apoE by extrahepatic tissues has also been proposed.
Abstract: The lipoprotein panel is a useful diagnostic tool that allows clinicians to evaluate blood lipoprotein fractions.
Until now several barriers have prevented applying what we know about remnant lipoproteins to clinical practice.
Moreover, the role of triglycerides-rich lipoproteins as a primary risk factor in patients at high risk for CAD has been established.
Lp(a) - a dangerous lipoprotein that contributes to clot formation
Reducing your intake of refined carbohydrates (such as those found in white bread, pasta, cakes, and cookies) in favor of lean protein and fiber-rich foods will also help to reduce postprandial lipoproteins.
Lipoproteins were originally classified as [alpha]-, [beta]- and pre-[beta]-lipoproteins according to their migration during electrophoresis.
The objective of the study, conducted by Quest Diagnostics Nichols Institute, was to describe and validate the ability of the ion mobility technique to directly and accurately measure plasma lipoprotein particles, covering the spectrum of HDL, LDL, IDL and VLDL in healthy adults.
LDL are the major lipoproteins responsible for delivery of exogenous cholesterol to the tissues.
have proposed age- and gender-specific thresholds that can be used to identify abnormal lipoprotein levels in adolescents that might put them at risk for cardiovascular disease later in life (Circulation 2006;114:1056-62).