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Porphyrinogen
In biochemistry a porphyrinogen is a member of a class of naturally occurring compounds with a tetrapyrrole core, a macrocycle Macrocycles are often described as molecules and ions containing a ring of twelve or more atoms. Classical examples include the crown ethers, calixarenes, porphyrins, and cyclodextrins. Macrocycles describe a large, mature area of chemistry. ... of four pyrrole rings connected by four methylene bridges. - IUPAC Gold Book They can be viewed as derived from the parent compound hexahydroporphine by the substitution of various functional groups for hydrogen atoms in the outermost (20-carbon) ring. Porphyrinogens are intermediates in the biosynthesis of porphyrins, Cofactor (biochemistry), cofactors with a porphine core which are found in many enzymes and proteins including myoglobin, hemoglobin, cytochromes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hexahydroporphine
Hexahydroporphine is an organic compound, organic chemical compound with formula . The molecule consists of four pyrrole rings connected by methylene bridges into a larger (non-aromatic (chemistry), aromatic) macrocycle ring, which makes it one of the simplest tetrapyrroles, and the simplest "true" one. As indicated by the name, it may be viewed as derived from porphine by the addition of six hydrogen atoms: four on the methine bridges, and two on the nitrogen atoms. Hexahydroporphine does not occur in nature, but is the core of porphyrinogens such as uroporphyrinogen III (UROGEN), which are precursors of many porphyrins — derivatives of porphine of great biological importance. The six hydrogens of that core are removed at a later metabolism, metabolic stage by the enzyme protoporphyrinogen oxidase. Because of this connection, the compound is also called (unsubstituted) porphyrinogen. The compound is a colorless solid, soluble in dichloromethane, acetone, and diethyl ether. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hexahydroporphine
Hexahydroporphine is an organic compound, organic chemical compound with formula . The molecule consists of four pyrrole rings connected by methylene bridges into a larger (non-aromatic (chemistry), aromatic) macrocycle ring, which makes it one of the simplest tetrapyrroles, and the simplest "true" one. As indicated by the name, it may be viewed as derived from porphine by the addition of six hydrogen atoms: four on the methine bridges, and two on the nitrogen atoms. Hexahydroporphine does not occur in nature, but is the core of porphyrinogens such as uroporphyrinogen III (UROGEN), which are precursors of many porphyrins — derivatives of porphine of great biological importance. The six hydrogens of that core are removed at a later metabolism, metabolic stage by the enzyme protoporphyrinogen oxidase. Because of this connection, the compound is also called (unsubstituted) porphyrinogen. The compound is a colorless solid, soluble in dichloromethane, acetone, and diethyl ether. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cytochrome
Cytochromes are redox-active proteins containing a heme, with a central Fe atom at its core, as a cofactor. They are involved in electron transport chain and redox catalysis. They are classified according to the type of heme and its mode of binding. Four varieties are recognized by the International Union of Biochemistry and Molecular Biology (IUBMB), cytochromes a, cytochromes b, cytochromes c and cytochrome d. Cytochrome function is linked to the reversible redox change from ferrous (Fe(II)) to the ferric (Fe(III)) oxidation state of the iron found in the heme core. In addition to the classification by the IUBMB into four cytochrome classes, several additional classifications such as cytochrome o and cytochrome P450 can be found in biochemical literature. History Cytochromes were initially described in 1884 by Charles Alexander MacMunn as respiratory pigments (myohematin or histohematin). In the 1920s, Keilin rediscovered these respiratory pigments and named them the c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lindsey Synthesis
Lindsey may refer to : Places Canada * Lindsey Lake, Nova Scotia England * Parts of Lindsey, one of the historic Parts of Lincolnshire and an administrative county from 1889 to 1974 ** East Lindsey, an administrative district in Lincolnshire, and a parliamentary constituency between 1983 and 1997 ** West Lindsey, an administrative district in Lincolnshire ** Kingdom of Lindsey, an early medieval kingdom in the area of modern Lincolnshire ** Archdeaconry of Lindsey, created in 1933 and absorbed into the Archdeaconry of Stow & Lindsey in 1994 * Lindsey, Suffolk * Norton Lindsey, Warwickshire United States * Lindsey, Ohio * Lindsey, Wisconsin * Lake Lindsey, Florida * Mount Lindsey, Colorado People * Lindsey (name) * Earl of Lindsey * Robert Bertie, 1st Duke of Ancaster and Kesteven, 1st Marquess of Lindsey Other uses * , a United States Navy destroyer-minelayer in commission from 1944 to 1946 See also * * Lindsay (other) * Linsay * Linsey (other) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protoporphyrin IX
Protoporphyrin IX is an organic compound, classified as a porphyrin, that plays an important role in living organisms as a precursor to other critical compounds like heme (hemoglobin) and chlorophyll. It is a deeply colored solid that is not soluble in water. The name is often abbreviated as PPIX. Protoporphyrin IX contains a porphine core, a tetrapyrrole macrocycle with a marked aromatic character. Protoporphyrin IX is essentially planar, except for the N-H bonds that are bent out of the plane of the rings, in opposite (trans) directions. Nomenclature The general term protoporphyrin refers to porphine derivatives that have the outer hydrogen atoms in the four pyrrole rings replaced by other functional groups. The prefix proto often means 'first' in science nomenclature (such as carbon protoxide), hence Hans Fischer is thought to have coined the name protoporphyrin as the first class of porphyrins. Fischer described iron-deprived heme becoming the "proto-" porphyrin, particu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protoporphyrinogen IX
Protoporphyrinogen IX is an organic chemical compound which is produced along the synthesis of porphyrins, a class of critical biochemicals that include hemoglobin and chlorophyll. It is a direct precursor of protoporphyrin IX. The compound is a porphyrinogen, meaning that it has a non-aromatic hexahydroporphine core, which will be oxidized to a porphine core in later stages of the heme synthesis. Like most porphyrinogens, it is colorless. Biosynthesis The compound is synthesized in most organisms from coproporphyrinogen III by the enzyme coproporphyrinogen oxidase: The process entails conversion of two of four propionic acid groups to vinyl groups. In coproporphyrinogen III, the substituents on the pyrrole rings have the arrangement MP-MP-MP-PM, where M and P are methyl and propionic acid, respectively. In protoporphyrinogen IX, the sequence becomes MV-MV-MP-PM, where V is vinyl. By the action of protoporphyrinogen oxidase, protoporphyrinogen IX is later converted into pro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coproporphyrinogen III
Coproporphyrinogen III is a metabolic intermediate in the biosynthesis of many compounds that are critical for living organisms, such as hemoglobin and chlorophyll. It is a colorless solid. The compound is a porphyrinogen, a class of compounds characterized by a hexahydroporphine core with various side chains. The coproporphyrinogens have the outermost hydrogen atoms of the core replaced by four methyl groups (M) and four propionic acid Propionic acid (, from the Greek words πρῶτος : ''prōtos'', meaning "first", and πίων : ''píōn'', meaning "fat"; also known as propanoic acid) is a naturally occurring carboxylic acid with chemical formula CH3CH2CO2H. It is a liq ... groups (P). In coproporphyrogen III, the order around the outer ring is MP-MP-MP-PM. For comparison, coproporphyrinogen I has them in the sequence MP-MP-MP-MP. heme. Biosynthesis and metabolism In the main Porphyrin#Synthesis, porphyrin biosynthesis pathway, coproporphyrinogen III is derived f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Uroporphyrinogen III
Uroporphyrinogen III is a tetrapyrrole, the first macrocyclic intermediate in the biosynthesis of heme, chlorophyll, vitamin B12, and siroheme. It is a colorless compound, like other porphyrinogens. Structure The molecular structure of uroporphyrinogen III can be described as a hexahydroporphine core, where each pyrrole ring has the hydrogen atoms on its two outermost carbons replaced by an acetic acid group (, "A") and a propionic acid group (, "P"). The groups are attached in an asymmetric way: going around the macrocycle, the order is AP-AP-AP-PA. Biosynthesis and metabolism In the general porphyrin biosynthesis pathway, uroporphyrinogen III is derived from the linear tetrapyrrole preuroporphyrinogen (a substituted hydroxymethylbilane) by the action of the enzyme uroporphyrinogen-III cosynthase. The conversion entails a reversal of the last pyrrole unit (thus swapping the acetic and propionic acid groups) and a condensation reaction that closes the macrocycle by eliminati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbon
Carbon () is a chemical element with the symbol C and atomic number 6. It is nonmetallic and tetravalent In chemistry, the valence (US spelling) or valency (British spelling) of an element is the measure of its combining capacity with other atoms when it forms chemical compounds or molecules. Description The combining capacity, or affinity of an ...—its atom making four electrons available to form covalent bond, covalent chemical bonds. It belongs to group 14 of the periodic table. Carbon makes up only about 0.025 percent of Earth's crust. Three Isotopes of carbon, isotopes occur naturally, Carbon-12, C and Carbon-13, C being stable, while Carbon-14, C is a radionuclide, decaying with a half-life of about 5,730 years. Carbon is one of the Timeline of chemical element discoveries#Ancient discoveries, few elements known since antiquity. Carbon is the 15th Abundance of elements in Earth's crust, most abundant element in the Earth's crust, and the Abundance of the c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phytotoxic
Phytotoxins are substances that are poisonous or toxic to the growth of plants. Phytotoxic substances may result from human activity, as with herbicides, or they may be produced by plants, by microorganisms, or by naturally occurring chemical reactions. The term is also used to describe toxic chemicals produced by plants themselves, which function as defensive agents against their predators. Most examples pertaining to this definition of phytotoxin are members of various classes of specialised or secondary metabolites, including alkaloids, terpenes, and especially phenolics, though not all such compounds are toxic or serve defensive purposes. Phytotoxins may also be toxic to humans. Toxins produced by plants Alkaloids Alkaloids are derived from amino acids, and contain nitrogen. They are medically important by interfering with components of the nervous system affecting membrane transport, protein synthesis, and enzyme activities. They generally have a bitter taste. Alkaloids ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coordination Compound
A coordination complex consists of a central atom or ion, which is usually metallic and is called the ''coordination centre'', and a surrounding array of bound molecules or ions, that are in turn known as ''ligands'' or complexing agents. Many metal-containing compounds, especially those that include transition metals (elements like titanium that belong to the Periodic Table's d-block), are coordination complexes. Nomenclature and terminology Coordination complexes are so pervasive that their structures and reactions are described in many ways, sometimes confusingly. The atom within a ligand that is bonded to the central metal atom or ion is called the donor atom. In a typical complex, a metal ion is bonded to several donor atoms, which can be the same or different. A polydentate (multiple bonded) ligand is a molecule or ion that bonds to the central atom through several of the ligand's atoms; ligands with 2, 3, 4 or even 6 bonds to the central atom are common. These compl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protoporphyrinogen Oxidase
Protoporphyrinogen oxidase or protox is an enzyme that in humans is encoded by the ''PPOX'' gene. Protoporphyrinogen oxidase is responsible for the seventh step in biosynthesis of protoporphyrin IX. This porphyrin is the precursor to hemoglobin, the oxygen carrier in animals, and chlorophyll, the dye in plants. The enzyme catalyzes the dehydrogenation (removal of hydrogen atoms) of protoporphyrinogen IX (the product of the sixth step in the production of heme) to form protoporphyrin IX. One additional enzyme must modify protoporphyrin IX before it becomes heme. Inhibition of this enzyme is a strategy used in certain herbicides. Gene The PPOX gene is located on the long (q) arm of chromosome 1 at position 22, from base pair 157,949,266 to base pair 157,954,082. Function This gene encodes the penultimate enzyme of heme biosynthesis, which catalyzes the 6-electron oxidation of protoporphyrinogen IX to form protoporphyrin IX. This protein is a flavoprotein associated with the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
