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Steviol
Steviol is a diterpene first isolated from the plant ''Stevia rebaudiana'' in 1931. Its chemical structure was not fully elucidated until 1960. Steviol occurs in the plant as steviol glycosides, sweet compounds that have found widespread use as sugar substitutes. The aglycon is prepared by enzymatic hydrolysis, since upon acid treatment steviol will undergo Wagner-Meerwein rearrangement to the very stable isosteviol. Biosynthesis In ''Stevia rebaudiana'', the biosynthesis of steviol is confined to green tissues. The precursors of steviol are synthesized via the non-mevalonate pathway located in plant cell plastids, which produces isopentenyl pyrophosphate (IPP) and dimethylallyl pyrophosphate (DMAPP). IPP and DMAPP are converted to geranylgeranyl diphosphate (GGDP), which is the precursor of many diterpenoids, by GGDP synthase. GPDP is made into a cyclic compound, copalyl diphosphate (CDP), by CDP synthase, after which kaurene is produced by another cyclization cataly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Steviol Glycoside
Steviol glycosides are the chemical compounds responsible for the sweet taste of the leaves of the South American plant ''Stevia rebaudiana'' (Asteraceae) and the main ingredients (or precursors) of many sweeteners marketed under the generic name stevia and several trade names. They also occur in the related species '' S. phlebophylla'' (but in no other species of ''Stevia'') and in the plant '' Rubus chingii'' (Rosaceae). Steviol glycosides from ''Stevia rebaudiana'' have been reported to be between 30 and 320 times sweeter than sucrose, although there is some disagreement in the technical literature about these numbers. They are heat-stable, pH-stable, and do not ferment. Steviol glycosides do not induce a glycemic response when ingested, because humans cannot metabolize stevia. The acceptable daily intake (ADI) for steviol glycosides, expressed as steviol equivalents, has been established to be 4 mg/kg body weight/day, and is based on no observed effects of a 100 fol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sugar Substitute
A sugar substitute is a food additive that provides a sweetness like that of sugar while containing significantly less food energy than sugar-based sweeteners, making it a zero-calorie () or low-calorie sweetener. Artificial sweeteners may be derived through manufacturing of plant extracts or processed by chemical synthesis. Sugar substitute products are commercially available in various forms, such as small pills, powders, and packets. In North America, common sugar substitutes include aspartame, monk fruit extract, saccharin, sucralose, and stevia; cyclamate is also used outside the United States. These sweeteners are a fundamental ingredient in diet drinks to sweeten them without adding calories. Additionally, sugar alcohols such as erythritol, xylitol, and sorbitol are derived from sugars. Approved artificial sweeteners do not cause cancer. Reviews and dietetic professionals have concluded that moderate use of non-nutritive sweeteners as a safe replacement for sugars can he ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ent-kaurene Synthase
The enzyme ''ent''-kaurene synthase (EC 4.2.3.19) catalyzes the chemical reaction :''ent''-copalyl diphosphate \rightleftharpoons ''ent''-kaurene + diphosphate This enzyme belongs to the family of lyases, specifically those carbon-oxygen lyases acting on phosphates. The systematic name of this enzyme class is ''ent''-copalyl-diphosphate diphosphate-lyase (cyclizing, ''ent''-kaurene-forming). Other names in common use include ''ent''-kaurene synthase B, ''ent''-kaurene synthetase B, ''ent''-copalyl-diphosphate diphosphate-lyase, and (cyclizing). This enzyme participates in diterpenoid biosynthesis. In ''Stevia'' In ''Stevia'' spp., ''ent''-kaurene synthase is a required part of the biosynthesis of steviol. Hajihashemi ''et al.'', 2013 find that it is involved in the drought stress response and because it mimics drought stress paclobutrazol toxicity. Both inhbit transcription of steviol glycoside Steviol glycosides are the chemical compounds responsible for the sweet taste of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stevia Rebaudiana
''Stevia rebaudiana'' is a plant species in the genus '' Stevia'' of the family Asteraceae. It is commonly known as candyleaf, sweetleaf or sugarleaf. It is a small seasonal plant which grows to a height of . It has elongated leaves that grow along the stems and are lined up against each other. The flowers are typically trimmed to improve the taste of the leaves. Stevia is a tender perennial native to parts of Brazil and Paraguay having humid, wet environments. Stevia is widely grown for its leaves, from which extracts can be manufactured as sweetener products known generically as stevia and sold under various trade names. The chemical compounds that produce its sweetness are various steviol glycosides (mainly stevioside and rebaudioside), which have 200–300 times the sweetness of sugar. Stevia leaves contain 9.1% stevioside and 3.8% rebaudioside A. Description The flowers are white with light purple accents and no fragrance. Plants produce fruit which is ribbed spindle-sh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Terpenoid
The terpenoids, also known as isoprenoids, are a class of naturally occurring organic chemicals derived from the 5-carbon compound isoprene and its derivatives called terpenes, diterpenes, etc. While sometimes used interchangeably with "terpenes", terpenoids contain additional functional groups, usually containing oxygen. When combined with the hydrocarbon terpenes, terpenoids comprise about 80,000 compounds. They are the largest class of plant secondary metabolites, representing about 60% of known natural products. Many terpenoids have substantial pharmacological bioactivity and are therefore of interest to medicinal chemists. Plant terpenoids are used for their aromatic qualities and play a role in traditional herbal remedies. Terpenoids contribute to the scent of eucalyptus, the flavors of cinnamon, cloves, and ginger, the yellow color in sunflowers, and the red color in tomatoes. Well-known terpenoids include citral, menthol, camphor, salvinorin A in the plant '' Salvia di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diterpene
Diterpenes are a class of chemical compounds composed of four isoprene units, often with the molecular formula C20H32. They are biosynthesized by plants, animals and fungi via the HMG-CoA reductase pathway, with geranylgeranyl pyrophosphate being a primary intermediate. Diterpenes form the basis for biologically important compounds such as retinol, retinal, and phytol. They are known to be antimicrobial and antiinflammatory. Structures As with most terpenes a huge number of potential structures exists, which may be broadly divided according to the number of rings present. Biosynthesis Diterpenes are derived from the addition of one IPP unit to FPP to form geranylgeranyl-pyrophosphate (GGPP). From GGPP, structural diversity is achieved mainly by two classes of enzymes; the diterpene synthases and cytochromes P450. Several diterpenes are produced by plants and cyanobacteria. GGPP is also the precursor for the synthesis of the phytane by the action of the enzyme geranylger ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Copalyl Diphosphate Synthase
In enzymology, a copalyl diphosphate synthase () is an enzyme that catalyzes the chemical reaction :geranylgeranyl diphosphate \rightleftharpoons (+)-copalyl diphosphate Hence, this enzyme has one substrate, geranylgeranyl diphosphate, and one product, (+)-copalyl diphosphate. This enzyme belongs to the family of isomerases, specifically the class of intramolecular lyases. The systematic name A systematic name is a name given in a systematic way to one unique group, organism, object or chemical substance, out of a specific population or collection. Systematic names are usually part of a nomenclature. A semisystematic name or semitrivial ... of this enzyme class is (+)-copalyl-diphosphate lyase (decyclizing). This enzyme participates in diterpenoid biosynthesis. References * * * * * EC 5.5.1 Enzymes of unknown structure {{isomerase-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diterpenes
Diterpenes are a class of chemical compounds composed of four isoprene units, often with the molecular formula C20H32. They are biosynthesized by plants, animals and fungi via the HMG-CoA reductase pathway, with geranylgeranyl pyrophosphate being a primary intermediate. Diterpenes form the basis for biologically important compounds such as retinol, retinal, and phytol. They are known to be antimicrobial and antiinflammatory. Structures As with most terpenes a huge number of potential structures exists, which may be broadly divided according to the number of rings present. Biosynthesis Diterpenes are derived from the addition of one IPP unit to FPP to form geranylgeranyl-pyrophosphate (GGPP). From GGPP, structural diversity is achieved mainly by two classes of enzymes; the diterpene synthases and cytochromes P450. Several diterpenes are produced by plants and cyanobacteria. GGPP is also the precursor for the synthesis of the phytane by the action of the enzyme geranylger ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bio Synthesis Of Steviol Glycoside 01
Bio or BIO may refer to: Computing * bio(4), a pseudo-device driver in RAID controller management interface in OpenBSD and NetBSD * Block I/O, a concept in computer data storage Politics * Julius Maada Bio (born 1964), Sierra Leonean politician, president since April 4, 2018 Media and entertainment * Bio (Australian TV channel) * The Biography Channel (UK and Ireland) * Bio (graffiti artist) Wilfredo Feliciano (born 1966) * ''Bio'' (album), a Chuck Berry album released in 1973 Organizations * Bedford Institute of Oceanography * Biographers International Organization * Biotechnology Innovation Organization * Belgian Investment Company for Developing Countries Energy * Biofuel, fuel made from biomass **Biodiesel, the biofuel alternative for diesel **Biogas, a blend of gasses formed by the breakdown of organic matter used in renewable energy production **Biogasoline, the biofuel alternative for gasoline Places * Bio, Azerbaijan, village in Astara Rayon * Bio, Lot, commune in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glycosylation
Glycosylation is the reaction in which a carbohydrate (or ' glycan'), i.e. a glycosyl donor, is attached to a hydroxyl or other functional group of another molecule (a glycosyl acceptor) in order to form a glycoconjugate. In biology (but not always in chemistry), glycosylation usually refers to an enzyme-catalysed reaction, whereas glycation (also 'non-enzymatic glycation' and 'non-enzymatic glycosylation') may refer to a non-enzymatic reaction (though in practice, 'glycation' often refers more specifically to Maillard-type reactions). Glycosylation is a form of co-translational and post-translational modification. Glycans serve a variety of structural and functional roles in membrane and secreted proteins. The majority of proteins synthesized in the rough endoplasmic reticulum undergo glycosylation. Glycosylation is also present in the cytoplasm and nucleus as the ''O''-GlcNAc modification. Aglycosylation is a feature of engineered antibodies to bypass glycosylation. Five clas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NADPH
Nicotinamide adenine dinucleotide phosphate, abbreviated NADP or, in older notation, TPN (triphosphopyridine nucleotide), is a cofactor used in anabolic reactions, such as the Calvin cycle and lipid and nucleic acid syntheses, which require NADPH as a reducing agent ('hydrogen source'). It is used by all forms of cellular life. NADPH is the reduced form of NADP. NADP differs from NAD by the presence of an additional phosphate group on the 2' position of the ribose ring that carries the adenine moiety. This extra phosphate is added by NAD+ kinase and removed by NADP+ phosphatase. Biosynthesis NADP In general, NADP+ is synthesized before NADPH is. Such a reaction usually starts with NAD+ from either the de-novo or the salvage pathway, with NAD+ kinase adding the extra phosphate group. ADP-ribosyl cyclase allows for synthesis from nicotinamide in the salvage pathway, and NADP+ phosphatase can convert NADPH back to NADH to maintain a balance. Some forms of the NAD+ kinas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ent-kaurenoic Acid Oxidase
Ent-kaurenoic acid oxidase () is an enzyme with systematic name ''ent-kaur-16-en-19-oate,NADPH:oxygen oxidoreductase (hydroxylating)''. This enzyme catalyses the following chemical reaction : ent-kaur-16-en-19-oate + 3 NADPH + 3 H+ + 3 O2 \rightleftharpoons gibberellin A12 + 3 NADP+ + 4 H2O (overall reaction) :(1a) ent-kaur-16-en-19-oate + NADPH + H+ + O2 \rightleftharpoons ent-7alpha-hydroxykaur-16-en-19-oate + NADP+ + H2O :(1b) ent-7alpha-hydroxykaur-16-en-19-oate + NADPH + H+ + O2 \rightleftharpoons gibberellin A12 aldehyde + NADP+ + 2 H2O :(1c) gibberellin A12 aldehyde + NADPH + H+ + O2 \rightleftharpoons gibberellin A12 + NADP+ + H2O Ent-kaurenoic acid oxidase requires cytochrome P450 Cytochromes P450 (CYPs) are a Protein superfamily, superfamily of enzymes containing heme as a cofactor (biochemistry), cofactor that functions as monooxygenases. In mammals, these proteins oxidize steroids, fatty acids, and xenobiotics, and are .... References External links * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
