Lipoprotein Lipase
An enzyme of the hydrolase class that catalyzes the reaction of triacylglycerol and water to yield diacylglycerol and a fatty acid anion. The enzyme hydrolyzes triacylglycerols in chylomicrons, very-low-density lipoproteins, low-density lipoproteins, and diacylglycerols. It occurs on capillary endothelial surfaces, especially in mammary, muscle, and adipose tissue. Genetic deficiency of the enzyme causes familial hyperlipoproteinemia Type I. (Dorland, 27th ed) EC 3.1.1.34.
Lipase
An enzyme of the hydrolase class that catalyzes the reaction of triacylglycerol and water to yield diacylglycerol and a fatty acid anion. It is produced by glands on the tongue and by the pancreas and initiates the digestion of dietary fats. (From Dorland, 27th ed) EC 3.1.1.3.
Lipoproteins
Lipid-protein complexes involved in the transportation and metabolism of lipids in the body. They are spherical particles consisting of a hydrophobic core of TRIGLYCERIDES and CHOLESTEROL ESTERS surrounded by a layer of hydrophilic free CHOLESTEROL; PHOSPHOLIPIDS; and APOLIPOPROTEINS. Lipoproteins are classified by their varying buoyant density and sizes.
Lipoproteins, LDL
A class of lipoproteins of small size (18-25 nm) and light (1.019-1.063 g/ml) particles with a core composed mainly of CHOLESTEROL ESTERS and smaller amounts of TRIGLYCERIDES. The surface monolayer consists mostly of PHOSPHOLIPIDS, a single copy of APOLIPOPROTEIN B-100, and free cholesterol molecules. The main LDL function is to transport cholesterol and cholesterol esters to extrahepatic tissues.
Lipoproteins, VLDL
A class of lipoproteins of very light (0.93-1.006 g/ml) large size (30-80 nm) particles with a core composed mainly of TRIGLYCERIDES and a surface monolayer of PHOSPHOLIPIDS and CHOLESTEROL into which are imbedded the apolipoproteins B, E, and C. VLDL facilitates the transport of endogenously made triglycerides to extrahepatic tissues. As triglycerides and Apo C are removed, VLDL is converted to INTERMEDIATE-DENSITY LIPOPROTEINS, then to LOW-DENSITY LIPOPROTEINS from which cholesterol is delivered to the extrahepatic tissues.
Lipoproteins, HDL
A class of lipoproteins of small size (4-13 nm) and dense (greater than 1.063 g/ml) particles. HDL lipoproteins, synthesized in the liver without a lipid core, accumulate cholesterol esters from peripheral tissues and transport them to the liver for re-utilization or elimination from the body (the reverse cholesterol transport). Their major protein component is APOLIPOPROTEIN A-I. HDL also shuttle APOLIPOPROTEINS C and APOLIPOPROTEINS E to and from triglyceride-rich lipoproteins during their catabolism. HDL plasma level has been inversely correlated with the risk of cardiovascular diseases.
Hyperlipoproteinemia Type I
An inherited condition due to a deficiency of either LIPOPROTEIN LIPASE or APOLIPOPROTEIN C-II (a lipase-activating protein). The lack of lipase activities results in inability to remove CHYLOMICRONS and TRIGLYCERIDES from the blood which has a creamy top layer after standing.
Triglycerides
Triglycerides are the most common type of fat in the body, stored in fat cells and used as energy; they are measured in blood tests to assess heart disease risk, with high levels often resulting from dietary habits, obesity, physical inactivity, smoking, and alcohol consumption.
Apolipoprotein C-II
A 9-kDa protein component of VERY-LOW-DENSITY LIPOPROTEINS. It contains a cofactor for LIPOPROTEIN LIPASE and activates several triacylglycerol lipases. The association of Apo C-II with plasma CHYLOMICRONS; VLDL, and HIGH-DENSITY LIPOPROTEINS is reversible and changes rapidly as a function of triglyceride metabolism. Clinically, Apo C-II deficiency is similar to lipoprotein lipase deficiency (HYPERLIPOPROTEINEMIA TYPE I) and is therefore called hyperlipoproteinemia type IB.
Lipoprotein(a)
A lipoprotein that resembles the LOW-DENSITY LIPOPROTEINS but with an extra protein moiety, APOPROTEIN (A) also known as APOLIPOPROTEIN (A), linked to APOLIPOPROTEIN B-100 on the LDL by one or two disulfide bonds. High plasma level of lipoprotein (a) is associated with increased risk of atherosclerotic cardiovascular disease.
Chylomicrons
A class of lipoproteins that carry dietary CHOLESTEROL and TRIGLYCERIDES from the SMALL INTESTINE to the tissues. Their density (0.93-1.006 g/ml) is the same as that of VERY-LOW-DENSITY LIPOPROTEINS.
Heparin
A highly acidic mucopolysaccharide formed of equal parts of sulfated D-glucosamine and D-glucuronic acid with sulfaminic bridges. The molecular weight ranges from six to twenty thousand. Heparin occurs in and is obtained from liver, lung, mast cells, etc., of vertebrates. Its function is unknown, but it is used to prevent blood clotting in vivo and vitro, in the form of many different salts.
Apolipoproteins C
A group of apolipoproteins that can readily exchange among the various classes of lipoproteins (HDL; VLDL; CHYLOMICRONS). After lipolysis of TRIGLYCERIDES on VLDL and chylomicrons, Apo-C proteins are normally transferred to HDL. The subtypes can modulate remnant binding to receptors, LECITHIN CHOLESTEROL ACYLTRANSFERASE, or LIPOPROTEIN LIPASE.
Apolipoproteins
Protein components on the surface of LIPOPROTEINS. They form a layer surrounding the hydrophobic lipid core. There are several classes of apolipoproteins with each playing a different role in lipid transport and LIPID METABOLISM. These proteins are synthesized mainly in the LIVER and the INTESTINES.
Receptors, Lipoprotein
Cell surface proteins that bind lipoproteins with high affinity. Lipoprotein receptors in the liver and peripheral tissues mediate the regulation of plasma and cellular cholesterol metabolism and concentration. The receptors generally recognize the apolipoproteins of the lipoprotein complex, and binding is often a trigger for endocytosis.
Lipolysis
The metabolic process of breaking down LIPIDS to release FREE FATTY ACIDS, the major oxidative fuel for the body. Lipolysis may involve dietary lipids in the DIGESTIVE TRACT, circulating lipids in the BLOOD, and stored lipids in the ADIPOSE TISSUE or the LIVER. A number of enzymes are involved in such lipid hydrolysis, such as LIPASE and LIPOPROTEIN LIPASE from various tissues.
Adipose Tissue
Specialized connective tissue composed of fat cells (ADIPOCYTES). It is the site of stored FATS, usually in the form of TRIGLYCERIDES. In mammals, there are two types of adipose tissue, the WHITE FAT and the BROWN FAT. Their relative distributions vary in different species with most adipose tissue being white.
Cholesterol
Lipids
A generic term for fats and lipoids, the alcohol-ether-soluble constituents of protoplasm, which are insoluble in water. They comprise the fats, fatty oils, essential oils, waxes, phospholipids, glycolipids, sulfolipids, aminolipids, chromolipids (lipochromes), and fatty acids. (Grant & Hackh's Chemical Dictionary, 5th ed)
Hypertriglyceridemia
A condition of elevated levels of TRIGLYCERIDES in the blood.
Apolipoproteins B
Major structural proteins of triacylglycerol-rich LIPOPROTEINS. There are two forms, apolipoprotein B-100 and apolipoprotein B-48, both derived from a single gene. ApoB-100 expressed in the liver is found in low-density lipoproteins (LIPOPROTEINS, LDL; LIPOPROTEINS, VLDL). ApoB-48 expressed in the intestine is found in CHYLOMICRONS. They are important in the biosynthesis, transport, and metabolism of triacylglycerol-rich lipoproteins. Plasma Apo-B levels are high in atherosclerotic patients but non-detectable in ABETALIPOPROTEINEMIA.
Receptors, LDL
Receptors on the plasma membrane of nonhepatic cells that specifically bind LDL. The receptors are localized in specialized regions called coated pits. Hypercholesteremia is caused by an allelic genetic defect of three types: 1, receptors do not bind to LDL; 2, there is reduced binding of LDL; and 3, there is normal binding but no internalization of LDL. In consequence, entry of cholesterol esters into the cell is impaired and the intracellular feedback by cholesterol on 3-hydroxy-3-methylglutaryl CoA reductase is lacking.
Cholesterol, HDL
Cholesterol which is contained in or bound to high-density lipoproteins (HDL), including CHOLESTEROL ESTERS and free cholesterol.
Lipoproteins, IDL
A mixture of very-low-density lipoproteins (VLDL), particularly the triglyceride-poor VLDL, with slow diffuse electrophoretic mobilities in the beta and alpha2 regions which are similar to that of beta-lipoproteins (LDL) or alpha-lipoproteins (HDL). They can be intermediate (remnant) lipoproteins in the de-lipidation process, or remnants of mutant CHYLOMICRONS and VERY-LOW-DENSITY LIPOPROTEINS which cannot be metabolized completely as seen in FAMILIAL DYSBETALIPOPROTEINEMIA.
Lipoprotein Lipase Activators
Compounds that increase the enzymatic activity of LIPOPROTEIN LIPASE. Lipoprotein lipase activators have a potential role in the treatment of OBESITY by increasing LIPID METABOLISM. Note that substances that increase the synthesis of lipoprotein lipase are not included here.
Liver
Apolipoproteins E
A class of protein components which can be found in several lipoproteins including HIGH-DENSITY LIPOPROTEINS; VERY-LOW-DENSITY LIPOPROTEINS; and CHYLOMICRONS. Synthesized in most organs, Apo E is important in the global transport of lipids and cholesterol throughout the body. Apo E is also a ligand for LDL receptors (RECEPTORS, LDL) that mediates the binding, internalization, and catabolism of lipoprotein particles in cells. There are several allelic isoforms (such as E2, E3, and E4). Deficiency or defects in Apo E are causes of HYPERLIPOPROTEINEMIA TYPE III.
Lipid Metabolism
Physiological processes in biosynthesis (anabolism) and degradation (catabolism) of LIPIDS.
Lipoproteins, HDL2
Low-density subclass of the high-density lipoproteins, with particle sizes between 8 to 13 nm.
Lipoproteins, HDL3
Intermediate-density subclass of the high-density lipoproteins, with particle sizes between 7 to 8 nm. As the larger lighter HDL2 lipoprotein, HDL3 lipoprotein is lipid-rich.
Cholesterol Esters
Fatty acid esters of cholesterol which constitute about two-thirds of the cholesterol in the plasma. The accumulation of cholesterol esters in the arterial intima is a characteristic feature of atherosclerosis.
Hyperlipoproteinemias
Conditions with abnormally elevated levels of LIPOPROTEINS in the blood. They may be inherited, acquired, primary, or secondary. Hyperlipoproteinemias are classified according to the pattern of lipoproteins on electrophoresis or ultracentrifugation.
Sterol Esterase
An enzyme that catalyzes the hydrolysis of CHOLESTEROL ESTERS and some other sterol esters, to liberate cholesterol plus a fatty acid anion.
Angiopoietins
Low Density Lipoprotein Receptor-Related Protein-1
A LDL-receptor related protein involved in clearance of chylomicron remnants and of activated ALPHA-MACROGLOBULINS from plasma.
Cholesterol, LDL
Cholesterol which is contained in or bound to low density lipoproteins (LDL), including CHOLESTEROL ESTERS and free cholesterol.
Monoacylglycerol Lipases
An enzyme that catalyzes the hydrolysis of glycerol monoesters of long-chain fatty acids EC 3.1.1.23.
Hyperlipidemias
Conditions with excess LIPIDS in the blood.
Apolipoprotein C-III
A 9-kDa protein component of VERY-LOW-DENSITY LIPOPROTEINS and CHYLOMICRON REMNANTS. Apo C-III, synthesized in the liver, is an inhibitor of LIPOPROTEIN LIPASE. Apo C-III modulates the binding of chylomicron remnants and VLDL to receptors (RECEPTORS, LDL) thus decreases the uptake of triglyceride-rich particles by the liver cells and subsequent degradation. The normal Apo C-III is glycosylated. There are several polymorphic forms with varying amounts of SIALIC ACID (Apo C-III-0, Apo C-III-1, and Apo C-III-2).
Apolipoproteins A
Structural proteins of the alpha-lipoproteins (HIGH DENSITY LIPOPROTEINS), including APOLIPOPROTEIN A-I and APOLIPOPROTEIN A-II. They can modulate the activity of LECITHIN CHOLESTEROL ACYLTRANSFERASE. These apolipoproteins are low in atherosclerotic patients. They are either absent or present in extremely low plasma concentration in TANGIER DISEASE.
Milk
The white liquid secreted by the mammary glands. It contains proteins, sugar, lipids, vitamins, and minerals.
Fatty Acids, Nonesterified
FATTY ACIDS found in the plasma that are complexed with SERUM ALBUMIN for transport. These fatty acids are not in glycerol ester form.
Cholesterol, VLDL
Cholesterol which is contained in or bound to very low density lipoproteins (VLDL). High circulating levels of VLDL cholesterol are found in HYPERLIPOPROTEINEMIA TYPE IIB. The cholesterol on the VLDL is eventually delivered by LOW-DENSITY LIPOPROTEINS to the tissues after the catabolism of VLDL to INTERMEDIATE-DENSITY LIPOPROTEINS, then to LDL.
Dietary Fats
Fats present in food, especially in animal products such as meat, meat products, butter, ghee. They are present in lower amounts in nuts, seeds, and avocados.
Apolipoprotein B-100
A 513-kDa protein synthesized in the LIVER. It serves as the major structural protein of low-density lipoproteins (LIPOPROTEINS, LDL; LIPOPROTEINS, VLDL). It is the ligand for the LDL receptor (RECEPTORS, LDL) that promotes cellular binding and internalization of LDL particles.
Heparin Lyase
An enzyme of the isomerase class that catalyzes the eliminative cleavage of polysaccharides containing 1,4-linked D-glucuronate or L-iduronate residues and 1,4-alpha-linked 2-sulfoamino-2-deoxy-6-sulfo-D-glucose residues to give oligosaccharides with terminal 4-deoxy-alpha-D-gluc-4-enuronosyl groups at their non-reducing ends. (From Enzyme Nomenclature, 1992) EC 4.2.2.7.
Fatty Acids
Organic, monobasic acids derived from hydrocarbons by the equivalent of oxidation of a methyl group to an alcohol, aldehyde, and then acid. Fatty acids are saturated and unsaturated (FATTY ACIDS, UNSATURATED). (Grant & Hackh's Chemical Dictionary, 5th ed)
Fasting
Abstaining from all food.
Arteriosclerosis
Thickening and loss of elasticity of the walls of ARTERIES of all sizes. There are many forms classified by the types of lesions and arteries involved, such as ATHEROSCLEROSIS with fatty lesions in the ARTERIAL INTIMA of medium and large muscular arteries.
Hyperlipoproteinemia Type IV
A hypertriglyceridemia disorder, often with autosomal dominant inheritance. It is characterized by the persistent elevations of plasma TRIGLYCERIDES, endogenously synthesized and contained predominantly in VERY-LOW-DENSITY LIPOPROTEINS (pre-beta lipoproteins). In contrast, the plasma CHOLESTEROL and PHOSPHOLIPIDS usually remain within normal limits.
Molecular Sequence Data
Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.
Emulsions
Colloids formed by the combination of two immiscible liquids such as oil and water. Lipid-in-water emulsions are usually liquid, like milk or lotion. Water-in-lipid emulsions tend to be creams. The formation of emulsions may be aided by amphiphatic molecules that surround one component of the system to form MICELLES.
Hyperlipidemia, Familial Combined
A type of familial lipid metabolism disorder characterized by a variable pattern of elevated plasma CHOLESTEROL and/or TRIGLYCERIDES. Multiple genes on different chromosomes may be involved, such as the major late transcription factor (UPSTREAM STIMULATORY FACTORS) on CHROMOSOME 1.
Apolipoprotein A-II
The second most abundant protein component of HIGH DENSITY LIPOPROTEINS or HDL. It has a high lipid affinity and is known to displace APOLIPOPROTEIN A-I from HDL particles and generates a stable HDL complex. ApoA-II can modulate the activation of LECITHIN CHOLESTEROL ACYLTRANSFERASE in the presence of APOLIPOPROTEIN A-I, thus affecting HDL metabolism.
Fat Emulsions, Intravenous
Emulsions of fats or lipids used primarily in parenteral feeding.
Cells, Cultured
RNA, Messenger
RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3' end, referred to as the poly(A) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm.
Apolipoprotein B-48
A 241-kDa protein synthesized only in the INTESTINES. It serves as a structural protein of CHYLOMICRONS. Its exclusive association with chylomicron particles provides an indicator of intestinally derived lipoproteins in circulation. Apo B-48 is a shortened form of apo B-100 and lacks the LDL-receptor region.
Cattle
Cholesterol Ester Transfer Proteins
Proteins that bind to and transfer CHOLESTEROL ESTERS between LIPOPROTEINS such as LOW-DENSITY LIPOPROTEINS and HIGH-DENSITY LIPOPROTEINS.
Macrophages
The relatively long-lived phagocytic cell of mammalian tissues that are derived from blood MONOCYTES. Main types are PERITONEAL MACROPHAGES; ALVEOLAR MACROPHAGES; HISTIOCYTES; KUPFFER CELLS of the liver; and OSTEOCLASTS. They may further differentiate within chronic inflammatory lesions to EPITHELIOID CELLS or may fuse to form FOREIGN BODY GIANT CELLS or LANGHANS GIANT CELLS. (from The Dictionary of Cell Biology, Lackie and Dow, 3rd ed.)
Colipases
Colipase I and II, consisting of 94-95 and 84-85 amino acid residues, respectively, have been isolated from porcine pancreas. Their role is to prevent the inhibitory effect of bile salts on the lipase-catalyzed intraduodenal hydrolysis of dietary long-chain triglycerides.
Ultracentrifugation
Insulin
A 51-amino acid pancreatic hormone that plays a major role in the regulation of glucose metabolism, directly by suppressing endogenous glucose production (GLYCOGENOLYSIS; GLUCONEOGENESIS) and indirectly by suppressing GLUCAGON secretion and LIPOLYSIS. Native insulin is a globular protein comprised of a zinc-coordinated hexamer. Each insulin monomer containing two chains, A (21 residues) and B (30 residues), linked by two disulfide bonds. Insulin is used as a drug to control insulin-dependent diabetes mellitus (DIABETES MELLITUS, TYPE 1).
Hypercholesterolemia
A condition with abnormally high levels of CHOLESTEROL in the blood. It is defined as a cholesterol value exceeding the 95th percentile for the population.
Phospholipids
Lipids containing one or more phosphate groups, particularly those derived from either glycerol (phosphoglycerides see GLYCEROPHOSPHOLIPIDS) or sphingosine (SPHINGOLIPIDS). They are polar lipids that are of great importance for the structure and function of cell membranes and are the most abundant of membrane lipids, although not stored in large amounts in the system.
Carrier Proteins
Base Sequence
Adipocytes
Cells in the body that store FATS, usually in the form of TRIGLYCERIDES. WHITE ADIPOCYTES are the predominant type and found mostly in the abdominal cavity and subcutaneous tissue. BROWN ADIPOCYTES are thermogenic cells that can be found in newborns of some species and hibernating mammals.
Amino Acid Sequence
Lipid Mobilization
LIPOLYSIS of stored LIPIDS in the ADIPOSE TISSUE to release FREE FATTY ACIDS. Mobilization of stored lipids is under the regulation of lipolytic signals (CATECHOLAMINES) or anti-lipolytic signals (INSULIN) via their actions on the hormone-sensitive LIPASE. This concept does not include lipid transport.
Hyperlipoproteinemia Type III
An autosomal recessively inherited disorder characterized by the accumulation of intermediate-density lipoprotein (IDL or broad-beta-lipoprotein). IDL has a CHOLESTEROL to TRIGLYCERIDES ratio greater than that of VERY-LOW-DENSITY LIPOPROTEINS. This disorder is due to mutation of APOLIPOPROTEINS E, a receptor-binding component of VLDL and CHYLOMICRONS, resulting in their reduced clearance and high plasma levels of both cholesterol and triglycerides.
Phosphatidylcholine-Sterol O-Acyltransferase
An enzyme secreted from the liver into the plasma of many mammalian species. It catalyzes the esterification of the hydroxyl group of lipoprotein cholesterol by the transfer of a fatty acid from the C-2 position of lecithin. In familial lecithin:cholesterol acyltransferase deficiency disease, the absence of the enzyme results in an excess of unesterified cholesterol in plasma. EC 2.3.1.43.
Cholesterol, Dietary
Cholesterol present in food, especially in animal products.
Myocardium
Hyperlipoproteinemia Type V
A severe type of hyperlipidemia, sometimes familial, that is characterized by the elevation of both plasma CHYLOMICRONS and TRIGLYCERIDES contained in VERY-LOW-DENSITY LIPOPROTEINS. Type V hyperlipoproteinemia is often associated with DIABETES MELLITUS and is not caused by reduced LIPOPROTEIN LIPASE activity as in HYPERLIPOPROTEINEMIA TYPE I .
Rats, Inbred Strains
Esterification
The process of converting an acid into an alkyl or aryl derivative. Most frequently the process consists of the reaction of an acid with an alcohol in the presence of a trace of mineral acid as catalyst or the reaction of an acyl chloride with an alcohol. Esterification can also be accomplished by enzymatic processes.
Polysaccharide-Lyases
Hyperlipoproteinemia Type II
A group of familial disorders characterized by elevated circulating cholesterol contained in either LOW-DENSITY LIPOPROTEINS alone or also in VERY-LOW-DENSITY LIPOPROTEINS (pre-beta lipoproteins).
Hypolipidemic Agents
Substances that lower the levels of certain LIPIDS in the BLOOD. They are used to treat HYPERLIPIDEMIAS.
Postprandial Period
The time frame after a meal or FOOD INTAKE.
Protein Binding
Heterozygote
Apolipoprotein E2
One of three major isoforms of apolipoprotein E. In humans, Apo E2 differs from APOLIPOPROTEIN E3 at one residue 158 where arginine is replaced by cysteine (R158--C). In contrast to Apo E3, Apo E2 displays extremely low binding affinity for LDL receptors (RECEPTORS, LDL) which mediate the internalization and catabolism of lipoprotein particles in liver cells. ApoE2 allelic homozygosity is associated with HYPERLIPOPROTEINEMIA TYPE III.
Adipose Tissue, Brown
A thermogenic form of adipose tissue composed of BROWN ADIPOCYTES. It is found in newborns of many species including humans, and in hibernating mammals. Brown fat is richly vascularized, innervated, and densely packed with MITOCHONDRIA which can generate heat directly from the stored lipids.
Oleic Acid
Body Weight
Mutation
Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.
Electrophoresis, Polyacrylamide Gel
Glycerides
GLYCEROL esterified with FATTY ACIDS.
Oleic Acids
A group of fatty acids that contain 18 carbon atoms and a double bond at the omega 9 carbon.
Chromatography, Affinity
Biological Transport
LDL-Receptor Related Protein-Associated Protein
A membrane protein found in the rough endoplasm reticulum (ENDOPLASMIC RETICULUM, ROUGH) that binds to LDL-RECEPTOR RELATED PROTEINS. It may function to prevent ligand binding of receptors during protein processing events within endosomal compartments.
Pancreas
A nodular organ in the ABDOMEN that contains a mixture of ENDOCRINE GLANDS and EXOCRINE GLANDS. The small endocrine portion consists of the ISLETS OF LANGERHANS secreting a number of hormones into the blood stream. The large exocrine portion (EXOCRINE PANCREAS) is a compound acinar gland that secretes several digestive enzymes into the pancreatic ductal system that empties into the DUODENUM.
Deoxyribonuclease HindIII
Cricetinae
Foam Cells
Lipid-laden macrophages originating from monocytes or from smooth muscle cells.
Oxidation-Reduction
A chemical reaction in which an electron is transferred from one molecule to another. The electron-donating molecule is the reducing agent or reductant; the electron-accepting molecule is the oxidizing agent or oxidant. Reducing and oxidizing agents function as conjugate reductant-oxidant pairs or redox pairs (Lehninger, Principles of Biochemistry, 1982, p471).
Atherosclerosis
Heparan Sulfate Proteoglycans
Ubiquitous macromolecules associated with the cell surface and extracellular matrix of a wide range of cells of vertebrate and invertebrate tissues. They are essential cofactors in cell-matrix adhesion processes, in cell-cell recognition systems, and in receptor-growth factor interactions. (From Cancer Metastasis Rev 1996; 15(2): 177-86; Hepatology 1996; 24(3): 524-32)
Binding Sites
Carboxylic Ester Hydrolases
Enzymes which catalyze the hydrolysis of carboxylic acid esters with the formation of an alcohol and a carboxylic acid anion.
Mice, Knockout
Strains of mice in which certain GENES of their GENOMES have been disrupted, or "knocked-out". To produce knockouts, using RECOMBINANT DNA technology, the normal DNA sequence of the gene being studied is altered to prevent synthesis of a normal gene product. Cloned cells in which this DNA alteration is successful are then injected into mouse EMBRYOS to produce chimeric mice. The chimeric mice are then bred to yield a strain in which all the cells of the mouse contain the disrupted gene. Knockout mice are used as EXPERIMENTAL ANIMAL MODELS for diseases (DISEASE MODELS, ANIMAL) and to clarify the functions of the genes.
Apoproteins
The protein components of a number of complexes, such as enzymes (APOENZYMES), ferritin (APOFERRITINS), or lipoproteins (APOLIPOPROTEINS).
Chromatography, Agarose
alpha-Macroglobulins
Glycoproteins with a molecular weight of approximately 620,000 to 680,000. Precipitation by electrophoresis is in the alpha region. They include alpha 1-macroglobulins and alpha 2-macroglobulins. These proteins exhibit trypsin-, chymotrypsin-, thrombin-, and plasmin-binding activity and function as hormonal transporters.
Scavenger Receptors, Class B
A family of scavenger receptors that are predominately localized to CAVEOLAE of the PLASMA MEMBRANE and bind HIGH DENSITY LIPOPROTEINS.
Hypolipoproteinemias
Conditions with abnormally low levels of LIPOPROTEINS in the blood. This may involve any of the lipoprotein subclasses, including ALPHA-LIPOPROTEINS (high-density lipoproteins); BETA-LIPOPROTEINS (low-density lipoproteins); and PREBETA-LIPOPROTEINS (very-low-density lipoproteins).
Protamines
A group of simple proteins that yield basic amino acids on hydrolysis and that occur combined with nucleic acid in the sperm of fish. Protamines contain very few kinds of amino acids. Protamine sulfate combines with heparin to form a stable inactive complex; it is used to neutralize the anticoagulant action of heparin in the treatment of heparin overdose. (From Merck Index, 11th ed; Martindale, The Extra Pharmacopoeia, 30th ed, p692)
Heparitin Sulfate
A heteropolysaccharide that is similar in structure to HEPARIN. It accumulates in individuals with MUCOPOLYSACCHARIDOSIS.
CHO Cells
CELL LINE derived from the ovary of the Chinese hamster, Cricetulus griseus (CRICETULUS). The species is a favorite for cytogenetic studies because of its small chromosome number. The cell line has provided model systems for the study of genetic alterations in cultured mammalian cells.
Antigens, CD36
Leukocyte differentiation antigens and major platelet membrane glycoproteins present on MONOCYTES; ENDOTHELIAL CELLS; PLATELETS; and mammary EPITHELIAL CELLS. They play major roles in CELL ADHESION; SIGNAL TRANSDUCTION; and regulation of angiogenesis. CD36 is a receptor for THROMBOSPONDINS and can act as a scavenger receptor that recognizes and transports oxidized LIPOPROTEINS and FATTY ACIDS.
Receptors, Immunologic
Gene Expression Regulation, Enzymologic
Apolipoprotein C-I
A 6.6-kDa protein component of VERY-LOW-DENSITY LIPOPROTEINS; INTERMEDIATE-DENSITY LIPOPROTEINS; and HIGH-DENSITY LIPOPROTEINS. Apo C-I displaces APO E from lipoproteins, modulate their binding to receptors (RECEPTORS, LDL), and thereby decrease their clearance from plasma. Elevated Apo C-I levels are associated with HYPERLIPOPROTEINEMIA and ATHEROSCLEROSIS.
Esterases
Esterases are hydrolase enzymes that catalyze the hydrolysis of ester bonds, converting esters into alcohols and acids, playing crucial roles in various biological processes including metabolism and detoxification.
Sodium Chloride
A ubiquitous sodium salt that is commonly used to season food.
Mice, Inbred C57BL
Inbred C57BL mice are a strain of laboratory mice that have been produced by many generations of brother-sister matings, resulting in a high degree of genetic uniformity and homozygosity, making them widely used for biomedical research, including studies on genetics, immunology, cancer, and neuroscience.
Rabbits
Obesity
A status with BODY WEIGHT that is grossly above the acceptable or desirable weight, usually due to accumulation of excess FATS in the body. The standards may vary with age, sex, genetic or cultural background. In the BODY MASS INDEX, a BMI greater than 30.0 kg/m2 is considered obese, and a BMI greater than 40.0 kg/m2 is considered morbidly obese (MORBID OBESITY).
Indolizines
Glycoproteins
Conjugated protein-carbohydrate compounds including mucins, mucoid, and amyloid glycoproteins.
Genotype
Glycerol
A trihydroxy sugar alcohol that is an intermediate in carbohydrate and lipid metabolism. It is used as a solvent, emollient, pharmaceutical agent, and sweetening agent.
Reference Values
Apolipoprotein E3
A 34-kDa glycosylated protein. A major and most common isoform of apolipoprotein E. Therefore, it is also known as apolipoprotein E (ApoE). In human, Apo E3 is a 299-amino acid protein with a cysteine at the 112 and an arginine at the 158 position. It is involved with the transport of TRIGLYCERIDES; PHOSPHOLIPIDS; CHOLESTEROL; and CHOLESTERYL ESTERS in and out of the cells.
Gene Expression
Enzyme Activation
Receptors, Scavenger
A large group of structurally diverse cell surface receptors that mediate endocytic uptake of modified LIPOPROTEINS. Scavenger receptors are expressed by MYELOID CELLS and some ENDOTHELIAL CELLS, and were originally characterized based on their ability to bind acetylated LOW-DENSITY LIPOPROTEINS. They can also bind a variety of other polyanionic ligand. Certain scavenger receptors can internalize micro-organisms as well as apoptotic cells.
Sepharose
Mice, Transgenic
Structure-Activity Relationship
Rhizopus
Phosphatidylcholines
Derivatives of phosphatidic acids in which the phosphoric acid is bound in ester linkage to a choline moiety. Complete hydrolysis yields 1 mole of glycerol, phosphoric acid and choline and 2 moles of fatty acids.
Apoprotein(a)
A large and highly glycosylated protein constituent of LIPOPROTEIN (A). It has very little affinity for lipids but forms disulfide-linkage to APOLIPOPROTEIN B-100. Apoprotein(a) has SERINE PROTEINASE activity and can be of varying sizes from 400- to 800-kDa. It is homologous to PLASMINOGEN and is known to modulate THROMBOSIS and FIBRINOLYSIS.
Dyslipidemias
Abnormalities in the serum levels of LIPIDS, including overproduction or deficiency. Abnormal serum lipid profiles may include high total CHOLESTEROL, high TRIGLYCERIDES, low HIGH DENSITY LIPOPROTEIN CHOLESTEROL, and elevated LOW DENSITY LIPOPROTEIN CHOLESTEROL.
Lactones
Cyclic esters of hydroxy carboxylic acids, containing a 1-oxacycloalkan-2-one structure. Large cyclic lactones of over a dozen atoms are MACROLIDES.
Blotting, Northern
Chromatography, Gel
Phospholipid Transfer Proteins
A ubiquitous family of proteins that transport PHOSPHOLIPIDS such as PHOSPHATIDYLINOSITOL and PHOSPHATIDYLCHOLINE between membranes. They play an important role in phospholipid metabolism during vesicular transport and SIGNAL TRANSDUCTION.
Coronary Disease
LDL-Receptor Related Proteins
A family of proteins that share sequence similarity with the low density lipoprotein receptor (RECEPTORS, LDL).
Sterol O-Acyltransferase
An enzyme that catalyzes the formation of cholesterol esters by the direct transfer of the fatty acid group from a fatty acyl CoA derivative. This enzyme has been found in the adrenal gland, gonads, liver, intestinal mucosa, and aorta of many mammalian species. EC 2.3.1.26.
Lipid Metabolism, Inborn Errors
Errors in the metabolism of LIPIDS resulting from inborn genetic MUTATIONS that are heritable.
Geotrichum
Starvation
Lengthy and continuous deprivation of food. (Stedman, 25th ed)