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Methemoglobin Reductase
Cytochrome-''b''5 reductase is a NADH-dependent enzyme that converts ferricytochrome from a Fe3+ form to a Fe2+ form. It contains FAD and catalyzes the reaction: In its b5-reducing capacity, this enzyme is involved in desaturation and elongation of fatty acids, cholesterol biosynthesis, and drug metabolism. This enzyme can also reduce methemoglobin to normal hemoglobin, gaining it the inaccurate synonym methemoglobin reductase. Isoforms expressed in erythrocytes (CYB5R1, CYB5R3) perform this function ''in vivo''. Ferricyanide is another substrate ''in vitro''. Introduction Cytochrome b5 reductase (c5br) is a NADH-dependent enzyme known as a flavoprotein that results in the chemical reduction to two different isoforms, a soluble form and a membrane-bound form. This enzyme is involved in the transfer of reducing equivalents from NADH due to the FAD electron acceptor in cytochrome b5, located in complex III of the electron transport chain, which results in the two isoforms due t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ribbon Diagram
Ribbon diagrams, also known as Richardson diagrams, are three-dimensional space, 3D schematic representations of protein structure and are one of the most common methods of protein depiction used today. The ribbon depicts the general course and organization of the protein backbone in 3D and serves as a visual framework for hanging details of the entire atomic structure, such as the balls for the oxygen atoms attached to myoglobin's active site in the adjacent figure. Ribbon diagrams are generated by interpolating a smooth curve through the polypeptide backbone. Alpha helix, α-helices are shown as coiled ribbons or thick tubes, Beta sheet, β-sheets as arrows, and non-repetitive coils or loops as lines or thin tubes. The direction of the Peptide, polypeptide chain is shown locally by the arrows, and may be indicated overall by a colour ramp along the length of the ribbon. Ribbon diagrams are simple yet powerful, expressing the visual basics of a molecular structure (twist, fold an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heme B
Heme B or haem B (also known as protoheme IX) is the most abundant heme. Hemoglobin and myoglobin are examples of oxygen transport proteins that contain heme B. The peroxidase family of enzymes also contain heme B. The COX-1 and COX-2 enzymes (cyclooxygenase) of recent fame, also contain heme B at one of two active sites. Generally, heme B is attached to the surrounding protein matrix (known as the apoprotein) through a single coordination bond between the heme iron and an amino-acid side-chain. Both hemoglobin and myoglobin have a coordination bond to an evolutionarily-conserved histidine, while nitric oxide synthase and cytochrome P450 have a coordination bond to an evolutionarily-conserved cysteine bound to the iron center of heme B. Since the iron in heme B containing proteins is bound to the four nitrogens of the porphyrin (forming a plane) and a single electron donating atom of the protein, the iron is often in a pentacoordinate state. When oxygen or the toxic carbon mon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glucose Oxidation Reaction
Glycolysis is the metabolic pathway that converts glucose () into pyruvate and, in most organisms, occurs in the liquid part of cells (the cytosol). The free energy released in this process is used to form the high-energy molecules adenosine triphosphate (ATP) and reduced nicotinamide adenine dinucleotide (NADH). Glycolysis is a sequence of ten reactions catalyzed by enzymes. The wide occurrence of glycolysis in other species indicates that it is an ancient metabolic pathway. Indeed, the reactions that make up glycolysis and its parallel pathway, the pentose phosphate pathway, can occur in the oxygen-free conditions of the Archean oceans, also in the absence of enzymes, catalyzed by metal ions, meaning this is a plausible prebiotic pathway for abiogenesis. The most common type of glycolysis is the ''Embden–Meyerhof–Parnas (EMP) pathway'', which was discovered by Gustav Embden, Otto Meyerhof, and Jakub Karol Parnas. Glycolysis also refers to other pathways, such as the '' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyridine Nucleotide Transferase
Pyridine nucleotide transferase may stand for * NAD(P)+ transhydrogenase (Re/Si-specific) * NAD(P)+ transhydrogenase (Si-specific) NAD or Nad may refer to: Geography * Nad, County Cork, a village in Ireland * North American Datum, a series of geographic coordinate systems * North Atlantic Drift, an Atlantic Ocean current * Hobli, a subdivision of a taluka in southern India ... {{Short pages monitor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ferric Ion
In chemistry, iron(III) or ''ferric'' refers to the element iron in its +3 oxidation state. ''Ferric chloride'' is an alternative name for iron(III) chloride (). The adjective ''ferrous'' is used instead for iron(II) salts, containing the cation Fe2+. The word ''ferric'' is derived from the Latin word , meaning "iron". Although often abbreviated as Fe3+, that naked ion does not exist except under extreme conditions. Iron(III) centres are found in many compounds and coordination complexes, where Fe(III) is bonded to several ligands. A molecular ferric complex is the anion ferrioxalate, , with three bidentate oxalate ions surrounding the Fe core. Relative to lower oxidation states, ferric is less common in organoiron chemistry, but the ferrocenium cation is well known. Iron(III) in biology All known forms of life require iron, which usually exists in Fe(II) or Fe(III) oxidation states. Many proteins in living beings contain iron(III) centers. Examples of such metalloproteins ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrogen Bond
In chemistry, a hydrogen bond (H-bond) is a specific type of molecular interaction that exhibits partial covalent character and cannot be described as a purely electrostatic force. It occurs when a hydrogen (H) atom, Covalent bond, covalently bonded to a more Electronegativity, electronegative donor atom or group (Dn), interacts with another electronegative atom bearing a lone pair of electrons—the hydrogen bond acceptor (Ac). Unlike simple Dipole–dipole attraction, dipole–dipole interactions, hydrogen bonding arises from charge transfer (nB → σ*AH), Atomic orbital, orbital interactions, and quantum mechanical Delocalized electron, delocalization, making it a resonance-assisted interaction rather than a mere electrostatic attraction. The general notation for hydrogen bonding is Dn−H···Ac, where the solid line represents a polar covalent bond, and the dotted or dashed line indicates the hydrogen bond. The most frequent donor and acceptor atoms are nitrogen (N), oxyg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diaphorase
Diaphorase may refer to: * Cytochrome b5 reductase, an enzyme * NADH dehydrogenase NADH dehydrogenase is an enzyme that converts nicotinamide adenine dinucleotide (NAD) from its reduced form (NADH) to its oxidized form (NAD+). Members of the NADH dehydrogenase family and analogues are commonly systematically named using the f ..., an enzyme * NADPH dehydrogenase, an enzyme See also * NADPH-diaphorase (other) {{Short pages monitor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxidoreductase
In biochemistry, an oxidoreductase is an enzyme that catalyzes the transfer of electrons from one molecule, the reductant, also called the electron donor, to another, the oxidant, also called the electron acceptor. This group of enzymes usually utilizes NADP+ or NAD+ as cofactors. Transmembrane oxidoreductases create electron transport chains in bacteria, chloroplasts and mitochondria, including respiratory complexes I, II and III. Some others can associate with biological membranes as peripheral membrane proteins or be anchored to the membranes through a single transmembrane helix. in Membranome database Reactions For e ...[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cytochrome B5 Reductase Structure
Cytochromes are redox-active proteins containing a heme, with a central iron (Fe) atom at its core, as a cofactor. They are involved in the 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reducing Equivalents
Reduction, reduced, or reduce may refer to: Science and technology Chemistry * Reduction (chemistry), part of a reduction-oxidation (redox) reaction in which atoms have their oxidation state changed. ** Organic redox reaction, a redox reaction that takes place with organic compounds ** Ore reduction: see smelting Computing and algorithms * Reduction (complexity), a transformation of one problem into another problem * Reduction (recursion theory), given sets A and B of natural numbers, is it possible to effectively convert a method for deciding membership in B into a method for deciding membership in A? * Bit Rate Reduction, an audio compression method * Data reduction, simplifying data in order to facilitate analysis * Graph reduction, an efficient version of non-strict evaluation * L-reduction, a transformation of optimization problems which keeps the approximability features * Partial order reduction, a technique for reducing the size of the state-space to be search ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phylogenetic Relationships
A phylogenetic tree or phylogeny is a graphical representation which shows the evolutionary history between a set of species or taxa during a specific time.Felsenstein J. (2004). ''Inferring Phylogenies'' Sinauer Associates: Sunderland, MA. In other words, it is a branching diagram or a tree showing the evolutionary relationships among various biological species or other entities based upon similarities and differences in their physical or genetic characteristics. In evolutionary biology, all life on Earth is theoretically part of a single phylogenetic tree, indicating common ancestry. Phylogenetics is the study of phylogenetic trees. The main challenge is to find a phylogenetic tree representing optimal evolutionary ancestry between a set of species or taxa. Computational phylogenetics (also phylogeny inference) focuses on the algorithms involved in finding optimal phylogenetic tree in the phylogenetic landscape. Phylogenetic trees may be rooted or unrooted. In a ''rooted'' phy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
