|
Dihydroflavonol 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 dihydromyricetin ( am ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enzymology
Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. Almost all metabolic processes in the 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 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 catalytic RNA molecules, called ribozymes. Enzymes' specificity comes from their unique three-dimensional structures. Like all catalysts, enzymes increase the reaction ra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leucoanthocyanidin
Leucoanthocyanidin (flavan-3,4-diols) are colorless chemical compounds related to anthocyanidins and anthocyanins. Leucoanthocyanins can be found in '' Anadenanthera peregrina'' and in several species of '' Nepenthes'' including '' N. burbidgeae'', '' N. muluensis'', '' N. rajah'', '' N. tentaculata'', and '' N. × alisaputrana''. Such compounds include: * Leucocyanidin * Leucodelphinidin * Leucofisetinidin * Leucomalvidin * Leucopelargonidin * Leucopeonidin * Leucorobinetinidin * Melacacidin * Teracacidin from '' Acacia obtusifolia'' and '' Acacia maidenii'' heartwoods Leucoanthocyanidins have been demonstrated to be intermediates in anthocyanidin biosynthesis in flowers of ''Matthiola incana''. Bate-smith recommended in 1954 the use of the Forestal solvent for the isolation of leuco-anthocyanins. Metabolism Leucoanthocyanidin dioxygenase uses flavan-3,4-diols to produce 3-hydroxyanthocyanidins. The gene encoding the enzyme (PpLDOX) ha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sinapyl Alcohol
Sinapyl alcohol is an organic compound structurally related to cinnamic acid. It is biosynthetized via the phenylpropanoid biochemical pathway, its immediate precursor being sinapaldehyde. This phytochemical is one of the monolignols, which are precursor to lignin or lignans. It is also a biosynthetic precursor to various stilbenoids and coumarins. See also *Sinapinic acid *Syringol *Syringaldehyde *Syringic acid *Acetosyringone *Sinapine *Canolol *Phenolic content in wine The phenolic content in wine refers to the phenolic compounds—natural phenol and polyphenols—in wine, which include a large group of several hundred chemical compounds that affect the taste, color and mouthfeel of wine. These compounds include ... References {{DEFAULTSORT:Sinapyl Alcohol Monolignols Ethers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coniferyl Aldehyde
Coniferyl aldehyde is an organic compound with the formula HO(CH3O)C6H3CH=CHCHO. It is a derivative of cinnamaldehyde, featuring 4-hydroxy and 3-methoxy substituents. It is a major precursor to lignin. Biosynthetic role In sweetgum (''Liquidambar styraciflua''), coniferyl aldehyde is a precursor to sinapaldehyde via hydroxylation mediated by coniferyl aldehyde 5-hydroxylase. Coniferyl aldehyde is reduced to coniferyl alcohol by the action of dehydrogenase enzymes. It is found in '' Senra incana'' (Hibisceae). It is a low molecular weight phenol that is susceptible to extraction from cork stoppers into wine.Polyphenolic Composition of Quercus suber Cork from Different Spanish Provenances. Elvira Conde, Estrella Cadahía, María Concepción García-Vallejo and Brígida Fernández de Simón, J. Agric. Food Chem., 1998, volume 46, pp 3166–3171 See also * Phenolic compounds in wine The phenolic content in wine refers to the phenolic compounds—natural phenol and polypheno ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sinapaldehyde
Sinapaldehyde is an organic compound with the formula HO(CH3O)2C6H2CH=CHCHO. It is a derivative of cinnamaldehyde, featuring one hydroxy group and two methoxy groups as substituents. It is an intermediate in the formation of sinapyl alcohol, a lignol that is a major precursor to lignin. Biosynthetic role In sweetgum (''Liquidambar styraciflua''), sinapaldehyde arises in two steps from coniferyl aldehyde beginning with hydroxylation mediated by coniferyl aldehyde 5-hydroxylase. The diphenol is then methylated at the 5-OH by the action of caffeate ''O''-methyltransferase. Sinapaldehyde is reduced to the alcohol by the action of dehydrogenase enzymes. In ''Arabidopsis thaliana'', the enzyme dihydroflavonol 4-reductase uses NADP+ to reduce sinapaldehyde to sinapyl alcohol. It is found in ''Senra incana'' (Hibisceae). It is a low molecular weight phenol that is susceptible to extraction from cork stoppers into wine.Polyphenolic Composition of ''Quercus suber'' Cork from Different ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arabidopsis Thaliana
''Arabidopsis thaliana'', the thale cress, mouse-ear cress or arabidopsis, is a small flowering plant native to Eurasia and Africa. ''A. thaliana'' is considered a weed; it is found along the shoulders of roads and in disturbed land. A winter annual with a relatively short lifecycle, ''A. thaliana'' is a popular model organism in plant biology and genetics. For a complex multicellular eukaryote, ''A. thaliana'' has a relatively small genome around 135 mega base pairs. It was the first plant to have its genome sequenced, and is a popular tool for understanding the molecular biology of many plant traits, including flower development and light sensing. Description ''Arabidopsis thaliana'' is an annual (rarely biennial) plant, usually growing to 20–25 cm tall. The leaves form a rosette at the base of the plant, with a few leaves also on the flowering stem. The basal leaves are green to slightly purplish in color, 1.5–5 cm long, and 2–10 mm broad, with an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lignin
Lignin is a class of complex organic polymers that form key structural materials in the support tissues of most plants. Lignins are particularly important in the formation of cell walls, especially in wood and bark, because they lend rigidity and do not rot easily. Chemically, lignins are polymers made by cross-linking phenolic precursors. History Lignin was first mentioned in 1813 by the Swiss botanist A. P. de Candolle, who described it as a fibrous, tasteless material, insoluble in water and alcohol but soluble in weak alkaline solutions, and which can be precipitated from solution using acid. He named the substance “lignine”, which is derived from the Latin word '' lignum'', meaning wood. It is one of the most abundant organic polymers on Earth, exceeded only by cellulose. Lignin constitutes 30% of non-fossil organic carbon on Earth, and 20 to 35% of the dry mass of wood. Lignin is present in red algae, which suggest that the common ancestor of plants and red algae ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blue Rose
A blue rose is a flower of the genus ''Rosa'' (family Rosaceae) that presents blue-to-violet pigmentation instead of the more common red, white, or yellow. Blue roses are often used to symbolize mystery or attaining the impossible. However, because of genetic limitations, they do not exist in nature. In 2004, researchers used genetic modification to create roses that contain the blue pigment delphinidin. So-called "blue roses" have been bred by conventional hybridization methods, but the results, such as "Blue Moon", are more accurately described as lilac in color. Dyed roses Since blue roses do not exist in nature, as roses lack the specific gene that has the ability to produce a "true blue" color, blue roses are traditionally created by dyeing white roses. In a book entitled ''Kitāb al-filāḥah'' written by Ibn al-'Awwām al-Ishbīlī in Arabic in the 12th century, and translated into French by J. J. Clement as ''Le livre de l'agriculture,'' there are references to azur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Delphinidin
Delphinidin (also delphinidine) is an anthocyanidin, a primary plant pigment, and also an antioxidant. Delphinidin gives blue hues to flowers in the genera ''Viola'' and ''Delphinium''. It also gives the blue-red color of the grape that produces Cabernet Sauvignon, and can be found in cranberries and Concord grapes as well as pomegranates, and bilberries. Delphinidin, like nearly all other anthocyanidins, is pH-sensitive, i.e. a natural pH indicator, and changes from blue in basic solution to red in acidic solution. Glycosides Several glycosides derived from delphinidin are known: *Myrtillin (delphinidin-3-''O''-glucoside) and tulipanin (delphinidin-3-''O''-rutinoside) can be found in blackcurrant pomace. *Violdelphin (delphinidin 3-rutinoside-7-''O''-(6-''O''-(4-(6-''O''-(4-hydroxybenzoyl)-β-D-glucosyl)oxybenzoyl)-β-D-glucoside) is responsible for the purplish-blue flower color of '' Aconitum chinense''. * Nasunin (delphinidin-3-(''p''-coumaroylrutinoside)-5-glucoside) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RNA Interference
RNA interference (RNAi) is a biological process in which RNA molecules are involved in sequence-specific suppression of gene expression by double-stranded RNA, through translational or transcriptional repression. Historically, RNAi was known by other names, including ''co-suppression'', ''post-transcriptional gene silencing'' (PTGS), and ''quelling''. The detailed study of each of these seemingly different processes elucidated that the identity of these phenomena were all actually RNAi. Andrew Fire and Craig C. Mello shared the 2006 Nobel Prize in Physiology or Medicine for their work on RNAi in the nematode worm '' Caenorhabditis elegans'', which they published in 1998. Since the discovery of RNAi and its regulatory potentials, it has become evident that RNAi has immense potential in suppression of desired genes. RNAi is now known as precise, efficient, stable and better than antisense therapy for gene suppression. Antisense RNA produced intracellularly by an expression vector m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bromheadia Finlaysoniana
''Bromheadia finlaysoniana'', commonly known as the pale reed orchid and as ''Bromheadia pulchra'' in Australia, is a plant in the orchid family and is native to areas from Indochina to northern Australia. It is a terrestrial orchid with a tough upright, stem and stiffly spreading, elliptic to egg-shaped leaves. There is a long flowering stem with a short zig-zag section near the end where single flowers open in succession. The flowers are white with a yellow labellum. Description ''Bromheadia finlaysoniana'' is a terrestrial, evergreen herb with flattened yellowish stems long with tough, stiffly spreading elliptic to egg-shaped leaves long and wide. The flowering stems is long with a short zig-zag end where up to seventy five single white flowers open in succession. The flowers are long, wide and are pinkish on the outside. The sepals are elliptic to egg-shaped, long and wide and the petals are egg-shaped and a similar length but broader than the sepals. The labellum ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
