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Sepiapterin Reductase (L-threo-7,8-dihydrobiopterin Forming)
Sepiapterin reductase (L-threo-7,8-dihydrobiopterin forming) () is an enzyme with systematic name ''L-threo-7,8-dihydrobiopterin:NADP+ oxidoreductase''. This enzyme catalyses the following chemical reaction : (1) L-threo-7,8-dihydrobiopterin + NADP+ \rightleftharpoons sepiapterin + NADPH + H+ : (2) L-threo-tetrahydrobiopterin + 2 NADP+ \rightleftharpoons 6-pyruvoyl-5,6,7,8-tetrahydropterin + 2 NADPH + 2 H+ This bacterial ('' Chlorobium tepidum'') enzyme catalyses the final step in the de novo synthesis of tetrahydrobiopterin Tetrahydrobiopterin (BH4, THB), also known as sapropterin (INN), is a cofactor of the three aromatic amino acid hydroxylase enzymes, used in the degradation of amino acid phenylalanine and in the biosynthesis of the neurotransmitters seroto ... from GTP. References External links * {{Portal bar, Biology, border=no EC 1.1.1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enzyme
Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different molecules known as product (chemistry), products. Almost all metabolism, metabolic processes in the cell (biology), cell need enzyme catalysis in order to occur at rates fast enough to sustain life. Metabolic pathways depend upon enzymes to catalyze individual steps. The study of enzymes is called ''enzymology'' and the field of pseudoenzyme, pseudoenzyme analysis recognizes that during evolution, some enzymes have lost the ability to carry out biological catalysis, which is often reflected in their amino acid sequences and unusual 'pseudocatalytic' properties. Enzymes are known to catalyze more than 5,000 biochemical reaction types. Other biocatalysts are Ribozyme, catalytic RNA molecules, called ribozymes. Enzymes' Chemical specificity, specific ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Enzymes
This article lists enzymes by their classification in the International Union of Biochemistry and Molecular Biology's Enzyme Commission (EC) numbering system. * List of EC numbers (EC 5) * List of EC numbers (EC 6) :Oxidoreductases (EC 1) ( Oxidoreductase) * Dehydrogenase *Luciferase * DMSO reductase :EC 1.1 (act on the CH-OH group of donors) * :EC 1.1.1 (with NAD+ or NADP+ as acceptor) ** Alcohol dehydrogenase (NAD) ** Alcohol dehydrogenase (NADP) ** Homoserine dehydrogenase ** Aminopropanol oxidoreductase **Diacetyl reductase ** Glycerol dehydrogenase ** Propanediol-phosphate dehydrogenase **glycerol-3-phosphate dehydrogenase (NAD+) **D-xylulose reductase ** L-xylulose reductase ** Lactate dehydrogenase ** Malate dehydrogenase ** Isocitrate dehydrogenase **HMG-CoA reductase * :EC 1.1.2 (with a cytochrome as acceptor) * :EC 1.1.3 (with oxygen as acceptor) ** Glucose oxidase ** L-gulonolactone oxidase ** Thiamine oxidase ** Xanthine oxidase * :EC 1.1. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Catalysis
Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recycles quickly, very small amounts of catalyst often suffice; mixing, surface area, and temperature are important factors in reaction rate. Catalysts generally react with one or more reactants to form intermediates that subsequently give the final reaction product, in the process of regenerating the catalyst. Catalysis may be classified as either homogeneous, whose components are dispersed in the same phase (usually gaseous or liquid) as the reactant, or heterogeneous, whose components are not in the same phase. Enzymes and other biocatalysts are often considered as a third category. Catalysis is ubiquitous in chemical industry of all kinds. Estimates are that 90% of all commercially produced chemical products involve catalysts at some st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemical Reaction
A chemical reaction is a process that leads to the chemical transformation of one set of chemical substances to another. Classically, chemical reactions encompass changes that only involve the positions of electrons in the forming and breaking of chemical bonds between atoms, with no change to the nuclei (no change to the elements present), and can often be described by a chemical equation. Nuclear chemistry is a sub-discipline of chemistry that involves the chemical reactions of unstable and radioactive elements where both electronic and nuclear changes can occur. The substance (or substances) initially involved in a chemical reaction are called reactants or reagents. Chemical reactions are usually characterized by a chemical change, and they yield one or more products, which usually have properties different from the reactants. Reactions often consist of a sequence of individual sub-steps, the so-called elementary reactions, and the information on the precise co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chlorobium Tepidum
''Chlorobaculum tepidum'', previously known as ''Chlorobium tepidum'', is an anaerobic, thermophilic green sulfur bacteria first isolated from New Zealand. Cells are gram-negative and non-motile rods of variable length. They contain bacteriochlorophyll c and chlorosomes. Genome structure ''Chlorobaculum tepidum'' contains a genome that contains 2.15 Mbp. There are a total of 2,337 genes (of these genes, there are 2,245 protein coding genes and 56 tRNA and rRNA coding genes). It synthesizes chlorophyll ''a'' and bacteriochlorophylls (BChls) ''a'' and ''c'' and is a model organism used to elucidate the biosynthesis of BChl ''c''. Several of its carotenoid metabolic pathways (including a novel lycopene cyclase) have similar counterparts in cyanobacteria. See also * List of bacterial orders * List of bacteria genera This article lists the genera of the bacteria. The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature (LPSN) and Nat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
De Novo Synthesis
In chemistry, ''de novo'' synthesis () refers to the synthesis of complex molecules from simple molecules such as sugars or amino acids, as opposed to recycling after partial degradation. For example, nucleotides are not needed in the diet as they can be constructed from small precursor molecules such as formate and aspartate. Methionine, on the other hand, is needed in the diet because while it can be degraded to and then regenerated from homocysteine, it cannot be synthesized ''de novo''. Nucleotide ''De novo'' pathways of nucleotides do not use free bases: adenine (abbreviated as A), guanine (G), cytosine (C), thymine (T), or uracil (U). The purine ring is built up one atom or a few atoms at a time and attached to ribose throughout the process. Pyrimidine ring is synthesized as orotate and attached to ribose phosphate and later converted to common pyrimidine nucleotides. Cholesterol Cholesterol is an essential structural component of animal cell membranes. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tetrahydrobiopterin
Tetrahydrobiopterin (BH4, THB), also known as sapropterin (INN), is a cofactor of the three aromatic amino acid hydroxylase enzymes, used in the degradation of amino acid phenylalanine and in the biosynthesis of the neurotransmitters serotonin (5-hydroxytryptamine, 5-HT), melatonin, dopamine, norepinephrine (noradrenaline), epinephrine (adrenaline), and is a cofactor for the production of nitric oxide (NO) by the nitric oxide synthases. Chemically, its structure is that of a (dihydropteridine reductase) reduced pteridine derivative (quinonoid dihydrobiopterin). Medical use Tetrahydrobiopterin is available as a tablet for oral administration in the form of ''sapropterin dihydrochloride'' (BH4*2HCL). It was approved for use in the United States as a tablet in December 2007 and as a powder in December 2013. It was approved for use in the European Union in December 2008, Canada in April 2010, and Japan in July 2008. It is sold under the brand names Kuvan and Biopten. The typ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
