A lipoprotein is a biochemical assembly that contains both proteins and lipids. The lipids or their derivatives may be covalently or non-covalently bound to the proteins. Many enzymes, transporters, structural proteins, antigens, adhesins and toxins are lipoproteins. Examples include the high density and low density lipoproteins of the blood, the transmembrane proteins of the mitochondrion and the chloroplast, and bacterial lipoproteins [1]. Biochemistry (from Greek: , bios, life and Egyptian kēme, earth[1]) is the study of the chemical processes in living organisms. ... A representation of the 3D structure of myoglobin, showing coloured alpha helices. ... Some common lipids. ... Ribbon diagram of the enzyme TIM, surrounded by the space-filling model of the protein. ... An antigen or immunogen is a molecule that stimulates an immune response. ... Adhesin Adhesins are antigens that may exist on the surface of microbes. ... For other uses, see Toxin (disambiguation). ... High-density lipoproteins (HDL) form a class of lipoproteins, varying somewhat in their size (8–11 nm in diameter), that carry cholesterol from the bodys tissues to the liver. ... Low-density lipoprotein (LDL) belongs to the lipoprotein particle family. ... Human blood smear: a - erythrocytes; b - neutrophil; c - eosinophil; d - lymphocyte. ... Cytochromes are generally membrane-bound proteins that contain heme groups and carry out electron transport or catalyse reductive/oxidative reactions. ... Electron micrograph of a mitochondrion showing its mitochondrial matrix and membranes In cell biology, a mitochondrion (plural mitochondria) is a membrane-enclosed organelle that is found in most eukaryotic cells. ... Chloroplasts are organelles found in plant cells and eukaryotic algae that conduct photosynthesis. ...

Function

The lipids are often an essential part of the complex, even if they seem to have no catalytic activity themselves. To isolate transmembrane lipoproteins from their associated membranes, detergents are often needed. A biological membrane or biomembrane is an enclosing or separating tissue which acts as a barrier within or around a cell. ... Laundry detergents are just one of many possible uses for detergents Detergent is a compound, or a mixture of compounds, intended to assist cleaning. ...

All cells use and rely on fats and, for all animal cells, cholesterol as building blocks to create the multiple membranes which cells use to both control internal water content, internal water soluble elements and to organize their internal structure and protein enzymatic systems. Drawing of the structure of cork as it appeared under the microscope to Robert Hooke from Micrographia which is the origin of the word cell being used to describe the smallest unit of a living organism Cells in culture, stained for keratin (red) and DNA (green) The cell is the... For other uses, see FAT. Fats consist of a wide group of compounds that are generally soluble in organic solvents and largely insoluble in water. ... For other uses, see Animal (disambiguation). ... Cholesterol is a sterol (a combination steroid and alcohol). ... Look up cell membrane in Wiktionary, the free dictionary. ...

Lipoproteins in the blood, a water medium, carry fats around the body. The protein particles have charged groups aimed outward so as to attract water molecules; this makes them soluble in the salt water based blood pool. Triglyceride-fats and cholesterol are carried internally, shielded by the protein particle from the water.

The interaction of the proteins forming the surface of the particles with (a) enzymes in the blood, (b) with each other and (c) with specific proteins on the surfaces of cells determine whether triglycerides and cholesterol will be added to or removed from the lipoprotein transport particles.

Regarding atheroma development and progression vs. regression, the key issue has always been cholesterol transport patterns, not cholesterol concentration itself. In pathology, an atheroma (plural: atheromata) is an accumulation and swelling (-oma) in artery walls that is made up of cells, or cell debris, that contain lipids (cholesterol and fatty acids), calcium and a variable amount of fibrous connective tissue. ...

Classification

By density

General categories of lipoproteins, listed in order from larger and less dense (more fat than protein) to smaller and more dense (more protein, less fat):

• Chylomicrons - carry triacylglycerol (fat) from the intestines to the liver and to adipose tissue.
• Very low density lipoproteins - carry (newly synthesised) triacylglycerol from the liver to adipose tissue.
• Intermediate density lipoproteins - are intermediate between VLDL and LDL. They are not usually detectable in the blood.
• Low density lipoproteins - carry cholesterol from the liver to cells of the body. Sometimes referred to as the "bad cholesterol" lipoprotein.[LDL]
• High density lipoproteins - collects cholesterol from the body's tissues, and brings it back to the liver. Sometimes referred to as the "good cholesterol" lipoprotein.[HDL]

Chylomicrons are large lipoprotein particles (having a diameter of 75 to 1,200nm) that are created by the absorptive cells of the small intestine. ... This article is about lipid molecules, for FAT see File Allocation Table. ... In anatomy, the intestine is the segment of the alimentary canal extending from the stomach to the anus and, in humans and other mammals, consists of two segments, the small intestine and the large intestine. ... For the bird, see Liver bird. ... Adipose tissue is one of the main types of connective tissue. ... Very Low Density Lipoprotein (VLDL) is a lipoprotein subclass. ... This article is about lipid molecules, for FAT see File Allocation Table. ... Intermediate density lipoproteins are a class of lipoproteins formed from the degradation of very low density lipoproteins, constituted essentially of triacylglycerols and cholesterol esters. ... Low-density lipoprotein (LDL) belongs to the lipoprotein particle family. ... High-density lipoproteins (HDL) form a class of lipoproteins, varying somewhat in their size (8–11 nm in diameter), that carry cholesterol from the bodys tissues to the liver. ...

Alpha and beta

It is also possible to classify lipoproteins as "alpha" and "beta", akin to the classification of proteins in serum protein electrophoresis. This terminolgy is sometimes used in describing lipid disorders such as Abetalipoproteinemia. Serum protein electrophoresis is a laboratory test that examines specific proteins in the blood called globulins. ... Abetalipoproteinemia is a rare genetic disorder (autosomal recessive) that interferes with the normal absorption of fat and fat soluble vitamins from food. ...

Lipoprotein(a)

Lipoprotein(a) - Lp(a), Cardiology diagnostic tests

Normal: <14mg/dL

High risk: >19mg/dL

How to lower: exercise, niacin, aspirin.

source: Beyond Cholesterol, Julius Torelli MD, 2005 ISBN 0-312-34863-0 p.91 The term Exercise can refer to: Physical exercise such as running or strength training Exercise (options), the financial term for enacting and terminating a contract Category: ... Niacin, also known as nicotinic acid or vitamin B3, is a water-soluble vitamin whose derivatives such as NADH, NAD, NAD+, and NADP play essential roles in energy metabolism in the living cell and DNA repair. ... This article is about the drug. ...

See also

• Apolipoprotein
• Lipid anchored protein
• Lipid anchor

To meet Wikipedias quality standards, this article or section may require cleanup. ... In lipid anchored proteins, a covalently attached fatty acid such as palmitate or myristate serves to anchor them to the cytoplasmic face of the cell membrane. ... In lipid anchored proteins, a covalently attached fatty acid such as palmitate or myristate serves to anchor them to the cytoplasmic face of the cell membrane. ...

External links

• Database of bacterial lipoproteins at mrc-lmb.cam.ac.uk
• Overview and diagram at washington.edu
• Lipoprotein assembly at wisc.edu
• Lipoprotein circulation at purdue.edu
• MeSH Lipoproteins
• MeSH Proteolipids