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Flavonoid Biosynthesis
Flavonoids are synthesized by the phenylpropanoid metabolic pathway in which the amino acid phenylalanine is used to produce 4-coumaroyl-CoA. This can be combined with malonyl-CoA to yield the true backbone of flavonoids, a group of compounds called chalcones, which contain two phenyl rings. Conjugate ring-closure of chalcones results in the familiar form of flavonoids, the three-ringed structure of a flavone. The metabolic pathway continues through a series of enzymatic modifications to yield flavanones → dihydroflavonols → anthocyanins. Along this pathway, many products can be formed, including the flavonols, flavan-3-ols, proanthocyanidins (tannins) and a host of other various polyphenolics. Flavanoids can possess chiral carbons. Methods of analysis should take this element into account especially regarding bioactivity or enzyme stereospecificity. Enzymes The biosynthesis of flavonoids involves several enzymes. * Anthocyanidin reductase * Chalcone isomerase * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flavonoid
Flavonoids (or bioflavonoids; from the Latin word ''flavus'', meaning yellow, their color in nature) are a class of polyphenolic secondary metabolites found in plants, and thus commonly consumed in the diets of humans. Chemically, flavonoids have the general structure of a 15-carbon skeleton, which consists of two phenyl rings (A and B) and a heterocyclic ring (C, the ring containing the embedded oxygen). This carbon structure can be abbreviated C6-C3-C6. According to the IUPAC nomenclature, they can be classified into: *flavonoids or bioflavonoids *isoflavonoids, derived from 3-phenyl chromen-4-one (3-phenyl-1,4-benzopyrone) structure *neoflavonoids, derived from 4-phenylcoumarine (4-phenyl-1,2-benzopyrone) structure The three flavonoid classes above are all ketone-containing compounds and as such, anthoxanthins ( flavones and flavonols). This class was the first to be termed bioflavonoids. The terms flavonoid and bioflavonoid have also been more loosely used to describe non ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stereospecificity
In chemistry, stereospecificity is the property of a reaction mechanism that leads to different stereoisomeric reaction products from different stereoisomeric reactants, or which operates on only one (or a subset) of the stereoisomers."Overlap Control of Carbanionoid Reactions. I. Stereoselectivity in Alkaline Epoxidation," Zimmerman, H. E.; Singer, L.; Thyagarajan, B. S. J. Am. Chem. Soc., 1959, 81, 108-116.Eliel, E., "Stereochemistry of Carbon Compound", McGraw-Hill, 1962 pp 434-436 In contrast, stereoselectivity is the property of a reactant mixture where a non-stereospecific mechanism allows for the formation of multiple products, but where one (or a subset) of the products is favored by factors, such as steric access, that are independent of the mechanism. A stereospecific mechanism ''specifies'' the stereochemical outcome of a given reactant, whereas a stereoselective reaction ''selects'' products from those made available by the same, non-specific mechanism acting on a g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leucocyanidin Oxygenase
In enzymology, a leucocyanidin oxygenase () is an enzyme that catalyzes the chemical reaction :leucocyanidin + 2-oxoglutarate + O2 \rightleftharpoons cis- and trans-dihydroquercetins + succinate + CO2 + 2 H2O The 3 substrates of this enzyme are leucocyanidin, 2-oxoglutarate, and O2, whereas its 5 products are cis-dihydroquercetin, trans-dihydroquercetin, succinate, CO2, and H2O. This enzyme belongs to the family of oxidoreductases, specifically those acting on paired donors, with O2 as oxidant and incorporation or reduction of oxygen. The oxygen incorporated need not be derived from O2 with 2-oxoglutarate as one donor, and incorporation of one atom o oxygen into each donor. The systematic name of this enzyme class is leucocyanidin,2-oxoglutarate:oxygen oxidoreductase. This enzyme is also called leucoanthocyanidin dioxygenase (LDOX) or anthocyanidin synthase (ANS). This enzyme participates in flavonoid biosynthesis. In a broader way, leucocyanidin oxygenase uses flavan-3, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leucoanthocyanidin Reductase
In enzymology, a leucoanthocyanidin reductase () (LAR, aka leucocyanidin reductase or LCR) is an enzyme that catalyzes the chemical reaction :(2R,3S)-catechin + NADP+ + H2O \rightleftharpoons 2,3-trans-3,4-cis-leucocyanidin + NADPH + H+ The 3 substrates of this enzyme are (2R,3S)-catechin, NADP+, and H2O, whereas its 3 products are 2,3-trans-3,4-cis-leucocyanidin, NADPH, and H+. This enzyme belongs to the family of oxidoreductases, specifically those acting on CH or CH2 groups with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class is (2R,3S)-catechin:NADP+ 4-oxidoreductase. This enzyme is also called leucocyanidin reductase. This enzyme participates in flavonoid biosynthesis. The enzyme can be found in the plant '' Hedysarum sulphurescens'' and in ''Vitis vinifera ''Vitis vinifera'', the common grape vine, is a species of flowering plant, native to the Mediterranean region, Central Europe, and southwestern Asia, from Morocco and Portugal north to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flavanone 4-reductase
In enzymology, a flavanone 4-reductase () is an enzyme that catalyzes the chemical reaction :(2S)-flavan-4-ol + NADP+ \rightleftharpoons (2S)-flavanone + NADPH + H+ Thus, the two substrates of this enzyme are (2S)-flavan-4-ol and NADP+, whereas its 3 products are (2S)-flavanone, NADPH, and H+. This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-OH group of donor with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class is (2S)-flavan-4-ol:NADP+ 4-oxidoreductase. This enzyme participates in flavonoid biosynthesis Flavonoids are synthesized by the phenylpropanoid metabolic pathway in which the amino acid phenylalanine is used to produce 4-coumaroyl-CoA. This can be combined with malonyl-CoA to yield the true backbone of flavonoids, a group of compounds .... References * EC 1.1.1 NADPH-dependent enzymes Enzymes of unknown structure Flavanones metabolism {{1.1.1-enzyme-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flavanone 3-dioxygenase
In enzymology, a flavanone 3-dioxygenase () is an enzyme that catalyzes the chemical reaction :a flavanone + 2-oxoglutarate + O2 \rightleftharpoons a dihydroflavonol + succinate + CO2 The 3 substrates of this enzyme are flavanone, 2-oxoglutarate, and O2, whereas its 3 products are dihydroflavonol, succinate, and CO2. This enzyme belongs to the family of oxidoreductases, specifically those acting on paired donors, with O2 as oxidant and incorporation or reduction of oxygen. The oxygen incorporated need not be derived from O2 with 2-oxoglutarate as one donor, and incorporation of one atom o oxygen into each donor. The systematic name of this enzyme class is flavanone,2-oxoglutarate:oxygen oxidoreductase (3-hydroxylating). Other names in common use include naringenin 3-hydroxylase, flavanone 3-hydroxylase, flavanone 3beta-hydroxylase, flavanone synthase I, (2S)-flavanone 3-hydroxylase, and naringenin,2-oxoglutarate:oxygen oxidoreductase (3-hydroxylating). This enzyme particip ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flavonol Synthase
In enzymology, a flavonol synthase () is an enzyme that catalysis, catalyzes the following chemical reaction : dihydroflavonol + 2-oxoglutarate + \rightleftharpoons a flavonol + succinate + C + H2O The 3 substrate (biochemistry), substrates of this enzyme are dihydroflavonol, 2-oxoglutarate, and oxygen, O2, whereas its 4 product (chemistry), products are flavonol, succinate, carbon dioxide, CO2, and water, H2O. This enzyme belongs to the family of oxidoreductases, specifically those acting on paired donors, with as oxidant and incorporation or reduction of oxygen. The oxygen incorporated need not be derived from with 2-oxoglutarate as one donor, and incorporation of one atom of oxygen into each donor. The List of enzymes, systematic name of this enzyme class is dihydroflavonol,2-oxoglutarate:oxygen oxidoreductase. This enzyme participates in flavonoid biosynthesis. References * * * * EC 1.14.11 Enzymes of unknown structure Flavonols metabolism {{1.14-enzyme ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flavonoid 3'-monooxygenase
In enzymology, a flavonoid 3'-monooxygenase (, was wrongly classified as in the past) is an enzyme that catalyzes the chemical reaction :a flavonoid + NADPH + H+ + O2 \rightleftharpoons a 3'-hydroxyflavonoid + NADP+ + H2O The 4 substrates of this enzyme are flavonoid, NADPH, H+, and O2, whereas its 3 products are 3'-hydroxyflavonoid, NADP+, and H2O. This enzyme belongs to the family of oxidoreductases, specifically those acting on paired donors, with O2 as oxidant and incorporation or reduction of oxygen. The oxygen incorporated need not be derived from O2 with NADH or NADPH as one donor, and incorporation of one atom of oxygen into the other donor. The systematic name of this enzyme class is flavonoid,NADPH:oxygen oxidoreductase (3'-hydroxylating). Other names in common use include flavonoid 3'-hydroxylase, flavonoid 3-hydroxylase (erroneous), NADPH:flavonoid-3'-hydroxylase, and flavonoid 3-monooxygenase (erroneous). This enzyme participates in flavonoid biosynthesis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flavone Synthase
In enzymology, a flavone synthase () is an enzyme that catalyzes the chemical reaction :a flavanone + 2-oxoglutarate + O2 \rightleftharpoons a flavone + succinate + CO2 + H2O The 3 substrates of this enzyme are flavanone, 2-oxoglutarate, and O2, whereas its 4 products are flavone, succinate, CO2, and H2O. This enzyme belongs to the family of oxidoreductases, specifically those acting on paired donors, with O2 as oxidant and incorporation or reduction of oxygen. The oxygen incorporated need not be derived from O2 with 2-oxoglutarate as one donor, and incorporation of one atom o oxygen into each donor. The systematic name of this enzyme class is flavanone,2-oxoglutarate:oxygen oxidoreductase (dehydrating). This enzyme participates in flavonoid biosynthesis and isoflavonoid biosynthesis The biosynthesis of isoflavonoids involves several enzymes; These are: Liquiritigenin,NADPH:oxygen oxidoreductase (hydroxylating, aryl migration), also known as Isoflavonoid synthase, is an en ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dihydrokaempferol 4-reductase
In enzymology, a dihydrokaempferol 4-reductase () is an enzyme that catalyzes the chemical reaction :cis-3,4- leucopelargonidin + NADP+ \rightleftharpoons (+)- dihydrokaempferol + NADPH + H+ Thus, the two substrates of this enzyme are cis-3,4-leucopelargonidin and NADP+, whereas its 3 products are (+)-dihydrokaempferol, NADPH, and H+. This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-OH group of donor with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class is cis-3,4-leucopelargonidin:NADP+ 4-oxidoreductase. Other names in common use include dihydroflavanol 4-reductase (DFR), dihydromyricetin reductase, NADPH-dihydromyricetin reductase, and dihydroquercetin reductase. This enzyme participates in flavonoid biosynthesis. Function Anthocyanidins, common plant pigments, are further reduced by the enzyme dihydroflavonol 4-reductase (DFR) to the corresponding colorless leucoanthocyanidins. DFR uses dihydromyriceti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chalcone Isomerase
In enzymology, a chalcone isomerase () is an enzyme that catalyzes the chemical reaction :a chalcone \rightleftharpoons a flavanone Hence, this enzyme has one substrate, a chalcone, and one product, a flavanone. This enzyme belongs to the family of isomerases, specifically the class of intramolecular lyases. The systematic name of this enzyme class is flavanone lyase (decyclizing). This enzyme is also called chalcone-flavanone isomerase. This enzyme participates in flavonoid biosynthesis. The ''Petunia hybrida'' (Petunia) genome contains two genes coding for very similar enzymes, ChiA and ChiB, but only the first seems to encode a functional chalcone isomerase. Structural studies As of late 2007, 7 structures have been solved for this class of enzymes, with PDB accession codes , , , , , , and . Chalcone isomerase has a core 2-layer alpha/beta structure A structure is an arrangement and organization of interrelated elements in a material object or system, or the object ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anthocyanidin Reductase
In enzymology, an anthocyanidin reductase () is an enzyme that catalyzes the chemical reaction :a flavan-3-ol + 2 NAD(P)+ \rightleftharpoons an anthocyanidin + 2 NAD(P)H + H+ The 3 substrates of this enzyme are flavan-3-ol, NAD+, and NADP+, whereas its 4 products are anthocyanidin, NADH, NADPH, and H+. This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-CH group of donor with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class is flavan-3-ol:NAD(P)+ oxidoreductase. Other names in common use include AtANR, and MtANR. This enzyme participates in flavonoid biosynthesis Flavonoids are synthesized by the phenylpropanoid metabolic pathway in which the amino acid phenylalanine is used to produce 4-coumaroyl-CoA. This can be combined with malonyl-CoA to yield the true backbone of flavonoids, a group of compounds .... References * * EC 1.3.1 NADPH-dependent enzymes NADH-dependent enzymes Enzymes of unknown ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
