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Phosphatidylglycerol
Phosphatidylglycerol is a glycerophospholipid found in pulmonary surfactant and in the plasma membrane where it directly activates lipid-gated ion channels. The general structure of phosphatidylglycerol consists of a L-glycerol 3-phosphate backbone ester-bonded to either saturated or unsaturated fatty acids on carbons 1 and 2. The head group substituent glycerol is bonded through a phosphomonoester. It is the precursor of surfactant and its presence (>0.3) in the amniotic fluid of the newborn indicates fetal lung maturity. Approximately 98% of alveolar wall surface area is due to the presence of type I cells, with type II cells producing pulmonary surfactant covering around 2% of the alveolar walls. Once surfactant is secreted by the type II cells, it must be spread over the remaining type I cellular surface area. Phosphatidylglycerol is thought to be important in spreading of surfactant over the Type I cellular surface area. The major surfactant deficiency in premature infants r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cardiolipin
Cardiolipin (IUPAC name 1,3-bis(''sn''-3’-phosphatidyl)-''sn''-glycerol, "''sn''" designating stereospecific numbering) is an important component of the inner mitochondrial membrane, where it constitutes about 20% of the total lipid composition. It can also be found in the membranes of most bacteria. The name "cardiolipin" is derived from the fact that it was first found in animal hearts. It was first isolated from the beef heart in the early 1940s by Mary C. Pangborn. In mammalian cells, but also in plant cells, cardiolipin (CL) is found almost exclusively in the inner mitochondrial membrane, where it is essential for the optimal function of numerous enzymes that are involved in mitochondrial energy metabolism. Structure Cardiolipin (CL) is a kind of diphosphatidylglycerol lipid. Two phosphatidic acid moieties connect with a glycerol backbone in the center to form a dimeric structure. So it has four alkyl groups and potentially carries two negative charges. As there are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pulmonary Surfactant
Pulmonary surfactant is a surface-active complex of phospholipids and proteins formed by Type II cells, type II alveolar cells. The proteins and lipids that make up the surfactant have both hydrophilic and hydrophobic regions. By adsorption, adsorbing to the air-water Interface (chemistry), interface of pulmonary alveolus, alveoli, with hydrophilic head groups in the water and the hydrophobic tails facing towards the air, the main lipid component of the surfactant, dipalmitoylphosphatidylcholine (DPPC), reduces surface tension. As a medication, Pulmonary surfactant (medication), pulmonary surfactant is on the WHO Model List of Essential Medicines, the most important medications needed in a basic health system. Function * To increase pulmonary compliance. * To prevent atelectasis (collapse of the alveoli or atriums) at the end of expiration. * To facilitate recruitment of collapsed airways. Alveoli can be compared to gas in water, as the alveoli are wet and surround a central a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lipid-gated Ion Channels
Lipid-gated ion channels are a class of ion channels whose conductance of ions through the membrane depends directly on lipids. Classically the lipids are membrane resident anionic signaling lipids that bind to the transmembrane domain on the inner leaflet of the plasma membrane with properties of a classic ligand. Other classes of lipid-gated channels include the mechanosensitive ion channels that respond to lipid tension, thickness, and hydrophobic mismatch. A lipid ligand differs from a lipid Cofactor (biochemistry), cofactor in that a Ligand (biochemistry), ligand derives its function by dissociating from the channel while a cofactor typically derives its function by remaining bound. PIP2-gated channels Phosphatidylinositol 4,5-bisphosphate (PIP2) was the first and remains the best studied lipid to gate ion channels. PIP2 is a cell membrane lipid, and its role in gating ion channels represents a novel role for the molecule. Kir channels: PIP2 binds to and directly activate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glycerophospholipid
Glycerophospholipids or phosphoglycerides are glycerol-based phospholipids. They are the main component of biological membranes in eukaryotic cells. They are a type of lipid, of which its composition affects membrane structure and properties. Two major classes are known: those for bacteria and eukaryotes and a separate family for archaea. Structures Glycerophospholipids are derived from glycerol-3-phosphate in a de novo pathway. The term glycerophospholipid signifies any derivative of glycerophosphoric acid that contains at least one ''O''- acyl, or ''O''-alkyl, or ''O''-alk-1'-enyl residue attached to the glycerol moiety. The phosphate group forms an ester linkage to the glycerol. The long-chained hydrocarbons are typically attached through ester linkages in bacteria/eukaryotes and by ether linkages in archaea. In bacteria and procaryotes, the lipids consist of diesters commonly of C16 or C18 fatty acids. These acids are straight-chained and, especially for the C18 membe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phospholipase D
Phospholipase D (PLD) (EC 3.1.4.4; also known as lipophosphodiesterase II, lecithinase D, choline phosphatase; systematic name: phosphatidylcholine phosphatidohydrolase) is an anesthetic-sensitive and mechanosensitive enzyme of the phospholipase protein superfamily that catalyzes the hydrolysis of membrane phospholipids. The canonical reaction is: :\text + \text_2\text \rightarrow \text + \text Phospholipases occur widely across bacteria, yeast, plants, animals, and viruses. PLD's principal substrate is phosphatidylcholine, which it hydrolyzes to produce the membrane lipid phosphatidic acid (PA) and soluble choline in a cholesterol-dependent process termed substrate presentation. Plants encode numerous PLD isoenzymes, with molecular weights ranging from approximately 90 to 125 kilodalton, kDa. In mammals, six PLD isoenzymes (PLD1–PLD6) are expressed. PLD1 and PLD2 are the best characterized, responsible for classical phosphatidylcholine hydrolysis and PA signaling. Other is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biosynthesis Of Phosphatidylglycerol, Phosphatidylserine, And Phosphatidylethanolamine
Biosynthesis, i.e., chemical synthesis occurring in biological contexts, is a term most often referring to multi-step, enzyme- catalyzed processes where chemical substances absorbed as nutrients (or previously converted through biosynthesis) serve as enzyme substrates, with conversion by the living organism either into simpler or more complex products. Examples of biosynthetic pathways include those for the production of amino acids, lipid membrane components, and nucleotides, but also for the production of all classes of biological macromolecules, and of acetyl-coenzyme A, adenosine triphosphate, nicotinamide adenine dinucleotide and other key intermediate and transactional molecules needed for metabolism. Thus, in biosynthesis, any of an array of compounds, from simple to complex, are converted into other compounds, and so it includes both the catabolism and anabolism (building up and breaking down) of complex molecules (including macromolecules). Biosynthetic processes are ofte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glycerol
Glycerol () is a simple triol compound. It is a colorless, odorless, sweet-tasting, viscous liquid. The glycerol backbone is found in lipids known as glycerides. It is also widely used as a sweetener in the food industry and as a humectant in pharmaceutical formulations. Because of its three hydroxyl groups, glycerol is miscible with water and is Hygroscopy, hygroscopic in nature. Modern use of the word glycerine (alternatively spelled glycerin) refers to commercial preparations of less than 100% purity, typically 95% glycerol. Structure Although chirality, achiral, glycerol is prochirality, prochiral with respect to reactions of one of the two primary alcohols. Thus, in substituted derivatives, the Glycerophospholipid#Nomenclature and stereochemistry, stereospecific numbering labels the molecule with a ''sn''- prefix before the stem name of the molecule. Production Natural sources Glycerol is generally obtained from plant and animal sources where it occurs in triglycerides, est ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phospholipids
Phospholipids are a class of lipids whose molecule has a hydrophilic "head" containing a phosphate group and two hydrophobic "tails" derived from fatty acids, joined by an alcohol residue (usually a glycerol molecule). Marine phospholipids typically have omega-3 fatty acids EPA and DHA integrated as part of the phospholipid molecule. The phosphate group can be modified with simple organic molecules such as choline, ethanolamine or serine. Phospholipids are a key component of all cell membranes. They can form lipid bilayers because of their amphiphilic characteristic. In eukaryotes, cell membranes also contain another class of lipid, sterol, interspersed among the phospholipids. The combination provides fluidity in two dimensions combined with mechanical strength against rupture. Purified phospholipids are produced commercially and have found applications in nanotechnology and materials science. The first phospholipid identified in 1847 as such in biological tissues was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
