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Phytoene Desaturase (3,4-didehydrolycopene-forming)
Phytoene desaturase (3,4-didehydrolycopene-forming) (, ''5-step phytoene desaturase'', ''five-step phytoene desaturase'', ''phytoene desaturase (ambiguous)'', ''Al-1'') is an enzyme with systematic name ''15-cis-phytoene:acceptor oxidoreductase (3,4-didehydrolycopene-forming)''. This enzyme catalyses the following chemical reaction : 15-''cis''- phytoene + 5 acceptor \rightleftharpoons all-''trans''-3,4- didehydrolycopene + 5 reduced acceptor (overall reaction) : (1a) 15-''cis''-phytoene + acceptor \rightleftharpoons all-''trans''-phytofluene + reduced acceptor : (1b) all-''trans''-phytofluene + acceptor \rightleftharpoons all-''trans''-''zeta''-carotene + reduced acceptor : (1c) all-''trans''-''zeta''-carotene + acceptor \rightleftharpoons all-''trans''-neurosporene + reduced acceptor : (1d) all-''trans''-neurosporene + acceptor \rightleftharpoons all-''trans''-lycopene + reduced acceptor : (1e) all-''trans''-lycopene + acceptor \rightleftharpoons all-''trans''-3,4-didehydr ... [...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] |
Phytoene
Phytoene () is a 40-carbon intermediate in the biosynthesis of carotenoids. The synthesis of phytoene is the first committed step in the synthesis of carotenoids in plants. Phytoene is produced from two molecules of geranylgeranyl pyrophosphate (GGPP) by the action of the enzyme phytoene synthase Phytoene synthase (, ''prephytoene-diphosphate synthase'', ''15-cis-phytoene synthase'', ''PSase'', ''geranylgeranyl-diphosphate geranylgeranyltransferase'') is a transferase enzyme involved in the biosynthesis of carotenoids. It catalyzes the conv .... The two GGPP molecules are condensed together followed by removal of diphosphate and proton shift leading to the formation of phytoene. Dietary phytoene and phytofluene are found in a number of human tissues including the liver, lung, breast, prostate, colon, and skin. Accumulation of these carotenoids in the skin may protect the skin by several mechanisms: acting as UV absorbers, as antioxidants, and as anti-inflammatory agents. Struct ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phytofluene
Phytofluene is a colorless carotenoid found naturally in tomatoes and other vegetables. It is the second product of carotenoid biosynthesis. It is formed from phytoene in a desaturation reaction leading to the formation of five conjugated double bonds. In the following step, addition of carbon-carbon conjugated double bonds leads to the formation of z-carotene and appearance of visible color. Phytofluene has an absorption spectra in the UVA range, with maximal absorption at 348 nm and with ε1% of 1557. Analysis of several fruits and vegetables showed that phytoene and phytofluene are found in majority of fruits and vegetables. In contrast to all other carotenoids, phytoene Phytoene () is a 40-carbon intermediate in the biosynthesis of carotenoids. The synthesis of phytoene is the first committed step in the synthesis of carotenoids in plants. Phytoene is produced from two molecules of geranylgeranyl pyrophosphate (G ... and phytofluene, the first carotenoid precursors i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neurosporene
Neurosporene is a carotenoid pigment. It is an intermediate in the biosynthesis of lycopene Lycopene is an organic compound classified as a tetraterpene and a carotene. Lycopene (from the neo-Latin '' Lycopersicum'', the tomato species) is a bright red carotenoid hydrocarbon found in tomatoes and other red fruits and vegetables. Occ ... and a variety of bacterial carotenoids. References Carotenoids {{organic-compound-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lycopene
Lycopene is an organic compound classified as a tetraterpene and a carotene. Lycopene (from the neo-Latin '' Lycopersicum'', the tomato species) is a bright red carotenoid hydrocarbon found in tomatoes and other red fruits and vegetables. Occurrence Aside from tomatoes, it is found in red carrots, watermelons, grapefruits, and papayas. It is not present in strawberries or cherries. It has no vitamin A activity. In plants, algae, and other photosynthetic organisms, lycopene is an intermediate in the biosynthesis of many carotenoids, including beta-carotene, which is responsible for yellow, orange, or red pigmentation, photosynthesis, and photoprotection. Like all carotenoids, lycopene is a tetraterpene. It is insoluble in water. Eleven conjugated double bonds give lycopene its deep red color. Owing to the strong color, lycopene is useful as a food coloring (registered as E160d) and is approved for use in the US, Australia and New Zealand (registered as 160d) and the Eu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carotenoid
Carotenoids (), also called tetraterpenoids, are yellow, orange, and red organic pigments that are produced by plants and algae, as well as several bacteria, and fungi. Carotenoids give the characteristic color to pumpkins, carrots, parsnips, corn, tomatoes, canaries, flamingos, salmon, lobster, shrimp, and daffodils. Carotenoids can be produced from fats and other basic organic metabolic building blocks by all these organisms. It is also produced by endosymbiotic bacteria in whiteflies. Carotenoids from the diet are stored in the fatty tissues of animals, and exclusively carnivorous animals obtain the compounds from animal fat. In the human diet, absorption of carotenoids is improved when consumed with fat in a meal. Cooking carotenoid-containing vegetables in oil and shredding the vegetable both increase carotenoid bioavailability. There are over 1,100 known carotenoids which can be further categorized into two classes, xanthophylls (which contain oxygen) and carotenes (which ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phytoene Desaturase (lycopene-forming)
Phytoene desaturase (lycopene-forming) (CrtI, ''four-step phytoene desaturase'') (, ''15-cis-phytoene:acceptor oxidoreductase (lycopene-forming)'') are enzymes found in archaea, bacteria and fungi that are involved in carotenoid biosynthesis. They catalyze the conversion of colorless 15-''cis''-phytoene into a bright red lycopene in a biochemical pathway called the poly-trans pathway. The same process in plants and cyanobacteria utilizes four separate enzymes in a poly-''cis'' pathway. Biochemistry Bacterial phytoene desaturases were shown to require FAD as a cofactor for their function. During the chemical reaction in total four additional double bonds are introduced into phytoene: : 15-''cis''-phytoene + 4 acceptor \rightleftharpoons all-''trans''-lycopene + 4 reduced acceptor (overall reaction) : (1a) 15-''cis''-phytoene + acceptor \rightleftharpoons all-''trans''-phytofluene + reduced acceptor : (1b) all-''trans''-phytofluene + acceptor \rightleftharpoons all-''trans''-' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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