|
Phospholipases2
A phospholipase is an enzyme that hydrolyzes phospholipids into fatty acids and other lipophilic substances. Acids trigger the release of bound calcium from cellular stores and the consequent increase in free cytosolic Ca2+, an essential step in calcium signaling to regulate intracellular processes. There are four major classes, termed A, B, C, and D, which are distinguished by the type of reaction which they catalyze: *Phospholipase A **Phospholipase A1 – cleaves the ''sn''-1 acyl chain (where ''sn'' refers to stereospecific numbering). **Phospholipase A2 – cleaves the ''sn''-2 acyl chain, releasing arachidonic acid. * Phospholipase B – cleaves both ''sn''-1 and ''sn''-2 acyl chains; this enzyme is also known as a lysophospholipase. *Phospholipase C – cleaves before the phosphate, releasing diacylglycerol and a phosphate-containing head group. PLCs play a central role in signal transduction, releasing the second messenger inositol triphosphate. * Phospholipase D – ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phospholipases2
A phospholipase is an enzyme that hydrolyzes phospholipids into fatty acids and other lipophilic substances. Acids trigger the release of bound calcium from cellular stores and the consequent increase in free cytosolic Ca2+, an essential step in calcium signaling to regulate intracellular processes. There are four major classes, termed A, B, C, and D, which are distinguished by the type of reaction which they catalyze: *Phospholipase A **Phospholipase A1 – cleaves the ''sn''-1 acyl chain (where ''sn'' refers to stereospecific numbering). **Phospholipase A2 – cleaves the ''sn''-2 acyl chain, releasing arachidonic acid. * Phospholipase B – cleaves both ''sn''-1 and ''sn''-2 acyl chains; this enzyme is also known as a lysophospholipase. *Phospholipase C – cleaves before the phosphate, releasing diacylglycerol and a phosphate-containing head group. PLCs play a central role in signal transduction, releasing the second messenger inositol triphosphate. * Phospholipase D – ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phospholipase D
Phospholipase D (EC 3.1.4.4, lipophosphodiesterase II, lecithinase D, choline phosphatase, PLD; systematic name phosphatidylcholine phosphatidohydrolase) is an enzyme of the phospholipase superfamily that catalyses the following reaction : a phosphatidylcholine + H2O = choline + a phosphatidate Phospholipases occur widely, and can be found in a wide range of organisms, including bacteria, yeast, plants, animals, and viruses. Phospholipase D's principal substrate is phosphatidylcholine, which it hydrolyzes to produce the signal molecule phosphatidic acid (PA), and soluble choline in a cholesterol dependent process called substrate presentation. Plants contain numerous genes that encode various PLD isoenzymes, with molecular weights ranging from 90 to 125 kDa. Mammalian cells encode two isoforms of phospholipase D: PLD1 and PLD2. Phospholipase D is an important player in many physiological processes, including membrane trafficking, cytoskeletal reorganization, receptor-mediated e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phospholipase A2
The enzyme phospholipase A2 (EC 3.1.1.4, PLA2, systematic name phosphatidylcholine 2-acylhydrolase) catalyse the cleavage of fatty acids in position 2 of phospholipids, hydrolyzing the bond between the second fatty acid “tail” and the glycerol molecule: :phosphatidylcholine + H2O = 1-acylglycerophosphocholine + a carboxylate This particular phospholipase specifically recognizes the ''sn''2 acyl bond of phospholipids and catalytically hydrolyzes the bond, releasing arachidonic acid and lysophosphatidic acid. Upon downstream modification by cyclooxygenases or lipoxygenases, arachidonic acid is modified into active compounds called eicosanoids. Eicosanoids include prostaglandins and leukotrienes, which are categorized as anti-inflammatory and inflammatory mediators. PLA2 enzymes are commonly found in mammalian tissues as well as arachnid, insect, and snake venom. Venom from bees is largely composed of melittin, which is a stimulant of PLA2. Due to the increased presenc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phospholipase B
Phospholipase B, also known as lysophospholipase, is an enzyme with a combination of both PLA1 and PLA2 activities; that is, it can cleave acyl chains from both the sn-1 and sn-2 positions of a phospholipid. In general, it acts on lysolecithin (which is formed by the action of PLA2 on lecithin). See also * Phospholipase A phospholipase is an enzyme that hydrolyzes phospholipids into fatty acids and other lipophilic substances. Acids trigger the release of bound calcium from cellular stores and the consequent increase in free cytosolic Ca2+, an essential step in ... References * {{Esterases ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phospholipase C
Phospholipase C (PLC) is a class of membrane-associated enzymes that cleave phospholipids just before the phosphate group (see figure). It is most commonly taken to be synonymous with the human forms of this enzyme, which play an important role in eukaryotic cell physiology, in particular signal transduction pathways. Phospholipase C's role in signal transduction is its cleavage of phosphatidylinositol 4,5-bisphosphate (PIP2) into diacyl glycerol (DAG) and inositol 1,4,5-trisphosphate (IP3), which serve as second messengers. Activators of each PLC vary, but typically include heterotrimeric G protein subunits, protein tyrosine kinases, small G proteins, Ca2+, and phospholipids. There are thirteen kinds of mammalian phospholipase C that are classified into six isotypes (β, γ, δ, ε, ζ, η) according to structure. Each PLC has unique and overlapping controls over expression and subcellular distribution. Variants Mammalian variants The extensive number of functions exerte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peripheral Membrane Proteins
Peripheral membrane proteins, or extrinsic membrane proteins, are membrane proteins that adhere only temporarily to the biological membrane with which they are associated. These proteins attach to integral membrane proteins, or penetrate the peripheral regions of the lipid bilayer. The regulatory protein subunits of many ion channels and transmembrane receptors, for example, may be defined as peripheral membrane proteins. In contrast to integral membrane proteins, peripheral membrane proteins tend to collect in the water-soluble component, or fraction, of all the proteins extracted during a protein purification procedure. Proteins with GPI anchors are an exception to this rule and can have purification properties similar to those of integral membrane proteins. The reversible attachment of proteins to biological membranes has shown to regulate cell signaling and many other important cellular events, through a variety of mechanisms. For example, the close association between many enzy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Infantile Neuroaxonal Dystrophy
Infantile neuroaxonal dystrophy is a rare pervasive developmental disorder that primarily affects the nervous system. Individuals with infantile neuroaxonal dystrophy typically do not have any symptoms at birth, but between the ages of about 6 and 18 months they begin to experience delays in acquiring new motor and intellectual skills, such as crawling or beginning to speak. Eventually they lose previously acquired skills. Cause This condition is inherited in an autosomal recessive pattern, which means two copies of the gene (''PLA2G6'') in each cell are altered. Most often, the parents of an individual with an autosomal recessive disorder each carry one copy of the altered gene but do not show signs and symptoms of the disorder. Pathophysiology Mutations in the ''PLA2G6'' gene have been identified in most individuals with infantile neuroaxonal dystrophy. The ''PLA2G6'' gene provides instructions for making an enzyme called an A2 phospholipase. This enzyme family is involved i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Patatin-like Phospholipase
Family of patatin-like phospholipases consists of various patatin glycoproteins from the total soluble protein from potato tubers, and also some proteins found in vertebrates. Patatin is a storage protein but it also has the enzymatic activity of phospholipase, catalysing the cleavage of fatty acids from membrane 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 ...s. Subfamilies *Protein of unknown function UPF0028 Human proteins containing this domain PNPLA1; PNPLA2; PNPLA3; PNPLA4; PNPLA5; PNPLA6; PNPLA7; PNPLA8; References {{InterPro content, IPR002641 Protein domains Protein families Single-pass transmembrane proteins Hydrolases ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Viperidae
The Viperidae (vipers) are a family of snakes found in most parts of the world, except for Antarctica, Australia, Hawaii, Madagascar, and various other isolated islands. They are venomous and have long (relative to non-vipers), hinged fangs that permit deep penetration and injection of their venom. Four subfamilies are currently recognized. They are also known as viperids. The name "viper" is derived from the Latin word ''vipera'', -''ae'', also meaning viper, possibly from ''vivus'' ("living") and ''parere'' ("to beget"), referring to the trait viviparity (giving live birth) common in vipers like most of the species of Boidae. Description All viperids have a pair of relatively long solenoglyphous (hollow) fangs that are used to inject venom from glands located towards the rear of the upper jaws, just behind the eyes. Each of the two fangs is at the front of the mouth on a short maxillary bone that can rotate back and forth. When not in use, the fangs fold back against the ro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blennies
Blenny (from the Greek and , mucus, slime) is a common name for many types of fish, including several families of percomorph marine, brackish, and some freshwater fish sharing similar morphology and behaviour. Six families are considered "true blennies", grouped under the order Blenniiformes; its members are referred to as blenniiformids. About 151 genera and nearly 900 species have been described within the order. The order was formerly classified as a suborder of the Perciformes but the 5th Edition of ''Fishes of the World'' divided the Perciformes into a number of new orders and the Blenniiformes were placed in the percomorph clade Ovalentaria alongside the such taxa as Cichliformes, Mugiliformes and Gobiesociformes. Families The six "true blenny" families are: * Blenniidae Rafinesque, 1810 - combtooth blennies, including the sabre-toothed blennies * Chaenopsidae Gill, 1865 - pikeblennies, tubeblennies and flagblennies * Clinidae Swainson, 1839 - clinids, inclu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lysolecithin
Lysophosphatidylcholines (LPC, lysoPC), also called lysolecithins, are a class of chemical compounds which are derived from phosphatidylcholines. Overview Lysophosphatidylcholines are produced within cells mainly by the enzyme phospholipase A2, which removes one of the fatty acid groups from phosphatidylcholine to produce LPC. Among other properties, they activate endothelial cells during early atherosclerosis. LPC also acts as a find-me signal, released by apoptotic cells to recruit phagocytes, which then phagocytose the apoptotic cells Moreover, LPCs can be used in the lab to cause demyelination of brain slices, to mimic the effects of demyelinating diseases such as multiple sclerosis. Further, they are known to stimulate phagocytosis of the myelin sheath and can change the surface properties of erythrocytes. LPC-induced demyelination is thought to occur through the actions of recruited macrophages and microglia which phagocytose nearby myelin. Invading T cells are also th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Histology And Histopathology
''Histology and Histopathology'' is a monthly peer-reviewed medical journal publishing original and review articles in the fields of histology and histopathology. It was established in 1986 and is published by the University of Murcia in Spain. The editors-in-chief are Francisco Hernández and Juan F. Madrid (University of Murcia). According to the ''Journal Citation Reports'', the journal has a 2016 impact factor The impact factor (IF) or journal impact factor (JIF) of an academic journal is a scientometric index calculated by Clarivate that reflects the yearly mean number of citations of articles published in the last two years in a given journal, as i ... of 2.025. References External links * Histopathology Pathology journals Anatomy journals Publications established in 1986 Quarterly journals University of Murcia English-language journals {{Medical-journal-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
