|
Lipid Transfer Protein
Plant lipid transfer proteins, also known as plant LTPs or PLTPs, are a group of highly- conserved proteins of about 7-9kDa found in higher plant tissues. As its name implies, lipid transfer proteins facilitate the shuttling of phospholipids and other fatty acid groups between cell membranes. LTPs are divided into two structurally related subfamilies according to their molecular masses: LTP1s (9 kDa) and LTP2s (7 kDa). Various LTPs bind a wide range of ligands, including fatty acids with a C10–C18 chain length, acyl derivatives of coenzyme A, phospho- and galactolipids, prostaglandin B2, sterols, molecules of organic solvents, and some drugs. The LTP domain is also found in seed storage proteins (including 2S albumin, gliadin, and glutelin) and bifunctional trypsin/ alpha-amylase inhibitors. These proteins share the same superhelical, disulfide-stabilised four-helix bundle containing an internal cavity. There is no sequence similarity between animal and plant LTPs. In animal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oryza Sativa
''Oryza sativa'', commonly known as Asian rice or indica rice, is the plant species most commonly referred to in English as ''rice''. It is the type of farmed rice whose cultivars are most common globally, and was first domesticated in the Yangtze River basin in China 13,500 to 8,200 years ago. ''Oryza sativa'' belongs to the genus '' Oryza'' of the grass family Poaceae. With a genome consisting of 430 Mbp across 12 chromosomes, it is renowned for being easy to genetically modify and is a model organism for the botany of cereals. Classification ''Oryza sativa'' contains two major subspecies: the sticky, short-grained ''japonica'' or ''sinica'' variety, and the nonsticky, long-grained ' rice variety. ''Japonica'' was domesticated in the Yangtze Valley 9–6,000 years ago, and its varieties can be cultivated in dry fields (it is cultivated mainly submerged in Japan), in temperate East Asia, upland areas of Southeast Asia, and high elevations in South Asia, while ''indica'' w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gliadin
Gliadin (a type of prolamin) is a class of proteins present in wheat and several other cereals within the grass genus ''Triticum''. Gliadins, which are a component of gluten, are essential for giving bread the ability to rise properly during baking. Gliadins and glutenins are the two main components of the gluten fraction of the wheat seed. This gluten is found in products such as wheat flour. Gluten is split about evenly between the gliadins and glutenins, although there are variations found in different sources. Both gliadins and glutenins are not water-soluble, but gliadins are soluble in 70% aqueous ethanol. There are three main types of gliadin (α, γ, and ω), to which the body is intolerant in coeliac (or celiac) disease. Diagnosis of this disease has recently been improving. Gliadin can cross the intestinal epithelium. Breast milk of healthy human mothers who eat gluten-containing foods presents high levels of non-degraded gliadin. Types The α, γ, and ω gliadin t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrophobicity
In chemistry, hydrophobicity is the physical property of a molecule that is seemingly repelled from a mass of water (known as a hydrophobe). In contrast, hydrophiles are attracted to water. Hydrophobic molecules tend to be nonpolar and, thus, prefer other neutral molecules and nonpolar solvents. Because water molecules are polar, hydrophobes do not dissolve well among them. Hydrophobic molecules in water often cluster together, forming micelles. Water on hydrophobic surfaces will exhibit a high contact angle. Examples of hydrophobic molecules include the alkanes, oils, fats, and greasy substances in general. Hydrophobic materials are used for oil removal from water, the management of oil spills, and chemical separation processes to remove non-polar substances from polar compounds. Hydrophobic is often used interchangeably with lipophilic, "fat-loving". However, the two terms are not synonymous. While hydrophobic substances are usually lipophilic, there are exceptions, suc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lipid Bilayer
The lipid bilayer (or phospholipid bilayer) is a thin polar membrane made of two layers of lipid molecules. These membranes are flat sheets that form a continuous barrier around all cells. The cell membranes of almost all organisms and many viruses are made of a lipid bilayer, as are the nuclear membrane surrounding the cell nucleus, and membranes of the membrane-bound organelles in the cell. The lipid bilayer is the barrier that keeps ions, proteins and other molecules where they are needed and prevents them from diffusing into areas where they should not be. Lipid bilayers are ideally suited to this role, even though they are only a few nanometers in width, because they are impermeable to most water-soluble (hydrophilic) molecules. Bilayers are particularly impermeable to ions, which allows cells to regulate salt concentrations and pH by transporting ions across their membranes using proteins called ion pumps. Biological bilayers are usually composed of amphiphilic phosphol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lipid
Lipids are a broad group of naturally-occurring molecules which includes fats, waxes, sterols, fat-soluble vitamins (such as vitamins A, D, E and K), monoglycerides, diglycerides, phospholipids, and others. The functions of lipids include storing energy, signaling, and acting as structural components of cell membranes. Lipids have applications in the cosmetic and food industries, and in nanotechnology. Lipids may be broadly defined as hydrophobic or amphiphilic small molecules; the amphiphilic nature of some lipids allows them to form structures such as vesicles, multilamellar/unilamellar liposomes, or membranes in an aqueous environment. Biological lipids originate entirely or in part from two distinct types of biochemical subunits or "building-blocks": ketoacyl and isoprene groups. Using this approach, lipids may be divided into eight categories: fatty acyls, glycerolipids, glycerophospholipids, sphingolipids, saccharolipids, and polyketides (derived from condensati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lipoprotein
A lipoprotein is a biochemical assembly whose primary function is to transport hydrophobic lipid (also known as fat) molecules in water, as in blood plasma or other extracellular fluids. They consist of a triglyceride and cholesterol center, surrounded by a phospholipid outer shell, with the hydrophilic portions oriented outward toward the surrounding water and lipophilic portions oriented inward toward the lipid center. A special kind of protein, called apolipoprotein, is embedded in the outer shell, both stabilising the complex and giving it a functional identity that determines its role. Many enzymes, transporters, structural proteins, antigens, adhesins, and toxins are lipoproteins. Examples include plasma lipoprotein particles ( HDL, LDL, IDL, VLDL and chylomicrons). Subgroups of these plasma particles are primary drivers or modulators of atherosclerosis. Scope Transmembrane lipoproteins Some transmembrane proteolipids, especially those found in bacteria, are referred ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Triglyceride
A triglyceride (TG, triacylglycerol, TAG, or triacylglyceride) is an ester derived from glycerol and three fatty acids (from ''tri-'' and ''glyceride''). Triglycerides are the main constituents of body fat in humans and other vertebrates, as well as vegetable fat. They are also present in the blood to enable the bidirectional transference of adipose fat and blood glucose from the liver, and are a major component of human skin oils. Many types of triglycerides exist. One specific classification focuses on saturated and unsaturated types. Saturated fats have ''no'' C=C groups; unsaturated fats feature one or more C=C groups. Unsaturated fats tend to have a lower melting point than saturated analogues; as a result, they are often liquid at room temperature. Chemical structure Triglycerides are tri-esters consisting of a glycerol bound to three fatty acid molecules. Alcohols have a hydroxyl (HO–) group. Organic acids have a carboxyl (–COOH) group. Alcohols and organ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cholesteryl Ester
300px, Cholesterol oleate, a member of the cholesteryl ester family Cholesteryl ester, a dietary lipid, is an ester of cholesterol. The ester bond is formed between the carboxylate group of a fatty acid and the hydroxyl group of cholesterol. Cholesteryl esters have a lower solubility in water due to their increased hydrophobicity. Esters are formed by replacing at least one –OH (hydroxyl) group with an –O–alkyl (alkoxy) group. They are hydrolyzed by pancreatic enzymes, cholesterol esterase, to produce cholesterol and free fatty acids. They are associated with atherosclerosis. Cholesteryl ester is found in human brains as lipid droplets which store and transport cholesterol. Increased levels of cholesteryl ester have been found in certain parts of the brain of people with Huntington disease. Higher concentrations of cholesteryl ester have been found in the caudate and putamen, but not the cerebellum, of people with Huntington Disease compared with levels in controls."Illawar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plasma Protein
Blood-proteins, also termed plasma proteins, are proteins present in blood plasma. They serve many different functions, including transport of lipids, hormones, vitamins and minerals in activity and functioning of the immune system. Other blood proteins act as enzymes, complement components, protease inhibitors or kinin precursors. Contrary to popular belief, haemoglobin is not a blood protein, as it is carried within red blood cells, rather than in the blood serum. Serum albumin accounts for 55% of blood proteins, is a major contributor to maintaining the oncotic pressure of plasma and assists, as a carrier, in the transport of lipids and steroid hormones. Globulins make up 38% of blood proteins and transport ions, hormones, and lipids assisting in immune function. Fibrinogen comprises 7% of blood proteins; conversion of fibrinogen to insoluble fibrin is essential for blood clotting. The remainder of the plasma proteins (1%) are regulatory proteins, such as enzymes, proenzymes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cholesteryl Ester Transfer Protein
Cholesteryl ester transfer protein (CETP), also called plasma lipid transfer protein, is a plasma protein that facilitates the transport of cholesteryl esters and triglycerides between the lipoproteins. It collects triglycerides from very-low-density (VLDL) or Chylomicrons and exchanges them for cholesteryl esters from high-density lipoproteins (HDL), and vice versa. Most of the time, however, CETP does a heteroexchange, trading a triglyceride for a cholesteryl ester or a cholesteryl ester for a triglyceride. Genetics The ''CETP'' gene is located on the sixteenth chromosome (16q21). Protein Fold The crystal structure of CETP is that of dimer of two TUbular LIPid (TULIP) binding domains. Each domain consists of a core of 6 elements: 4 beta-sheets forming an extended superhelix; 2 flanking elements that tend to include some alpha helix. The sheets wrap around the helices to produce a cylinder 6 x 2.5 x 2.5 nm. CETP contains two of these domains that interact head-to-head ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Disulfide
In biochemistry, a disulfide (or disulphide in British English) refers to a functional group with the structure . The linkage is also called an SS-bond or sometimes a disulfide bridge and is usually derived by the coupling of two thiol groups. In biology, disulfide bridges formed between thiol groups in two cysteine residues are an important component of the secondary and tertiary structure of proteins. ''Persulfide'' usually refers to compounds. In inorganic chemistry disulfide usually refers to the corresponding anion (−S−S−). Organic disulfides Symmetrical disulfides are compounds of the formula . Most disulfides encountered in organo sulfur chemistry are symmetrical disulfides. Unsymmetrical disulfides (also called heterodisulfides) are compounds of the formula . They are less common in organic chemistry, but most disulfides in nature are unsymmetrical. Properties The disulfide bonds are strong, with a typical bond dissociation energy of 60 kcal/mol (251&nbs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acta Crystallographica D
''Acta Crystallographica'' is a series of peer-reviewed scientific journals, with articles centred on crystallography, published by the International Union of Crystallography (IUCr). Originally established in 1948 as a single journal called ''Acta Crystallographica'', there are now six independent ''Acta Crystallographica'' titles: *'' Acta Crystallographica Section A: Foundations and Advances'' *'' Acta Crystallographica Section B: Structural Science, Crystal Engineering and Materials'' *'' Acta Crystallographica Section C: Structural Chemistry'' *'' Acta Crystallographica Section D: Structural Biology'' *'' Acta Crystallographica Section E: Crystallographic Communications'' *'' Acta Crystallographica Section F: Structural Biology Communications'' ''Acta Crystallographica'' has been noted for the high quality of the papers that it produces, as well as the large impact that its papers have had on the field of crystallography. The current six journals form part of the journal portf ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
