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Shikimate Pathway
The shikimate pathway (shikimic acid pathway) is a seven-step metabolic pathway used by bacteria, archaea, fungi, algae, some protozoans, and plants for the biosynthesis of folates and aromatic amino acids (tryptophan, phenylalanine, and tyrosine). This pathway is not found in mammals. The five enzymes involved in the shikimate pathway are 3-dehydroquinate dehydratase, shikimate dehydrogenase, shikimate kinase, EPSP synthase, and chorismate synthase. In bacteria and eurkaryotes, the pathway starts with two substrates, phosphoenol pyruvate and erythrose-4-phosphate, are processed by DAHP synthase and 3-dehydroquinate synthase to form 3-dehydroquinate. In archaea, 2-amino-3,7-dideoxy-D-threo-hept-6-ulosonate synthase condenses L-Aspartic-4-semialdehyde with a sugar to form 2-amino-3,7-dideoxy-D-threo-hept-6-ulosonate, which is then turned by 3-dehydroquinate synthase II into 3-dehydroquinate. Both pathways end with chorismate (chrorismic acid), a substrate for the thre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Shikimic Acid
Shikimic acid, more commonly known as its anionic form shikimate, is a cyclohexene, a cyclitol and a cyclohexanecarboxylic acid. It is an important biochemical metabolite in plants and microorganisms. Its name comes from the Japanese flower ''shikimi'' (, the Japanese star anise, ''Illicium anisatum''), from which it was first isolated in 1885 by Johan Fredrik Eykman. The elucidation of its structure was made nearly 50 years later. Biosynthesis Phosphoenolpyruvate and erythrose-4-phosphate condense to form 3-deoxy-D-arabinoheptulosonate-7-phosphate (DAHP), in a reaction catalyzed by the enzyme DAHP synthase. DAHP is then transformed to 3-dehydroquinate (DHQ), in a reaction catalyzed by DHQ synthase. Although this reaction requires nicotinamide adenine dinucleotide (NAD) as a cofactor, the enzymic mechanism regenerates it, resulting in the net use of no NAD. : DHQ is dehydrated to 3-dehydroshikimic acid by the enzyme 3-dehydroquinate dehydratase, which is reduced to sh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
EPSP Synthase
5-enolpyruvylshikimate-3-phosphate (EPSP) synthase is an enzyme produced by plants and microorganisms. EPSPS catalyzes the chemical reaction: : phosphoenolpyruvate (PEP) + 3-phospho shikimate (S3P) phosphate + 5-enolpyruvylshikimate-3-phosphate (EPSP) Thus, the two substrates of this enzyme are phosphoenolpyruvate (PEP) and 3-phosphoshikimate, whereas its two products are phosphate and 5-enolpyruvylshikimate-3-phosphate. This enzyme is absent from animal genomes, making it an attractive target for herbicides such as glyphosate. A glyphosate-resistant version of the enzyme's gene has been incorporated into genetically modified crops. Nomenclature The enzyme belongs to the family of transferases, to be specific those transferring aryl or alkyl groups other than methyl groups. The systematic name of this enzyme class is phosphoenolpyruvate:3-phosphoshikimate 5-''O''-(1-carboxyvinyl)-transferase. Other names in common use include: * 5-enolpyruvylshikimate-3-phosphate synth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Adenosine Triphosphate
Adenosine triphosphate (ATP) is a nucleoside triphosphate that provides energy to drive and support many processes in living cell (biology), cells, such as muscle contraction, nerve impulse propagation, and chemical synthesis. Found in all known forms of life, it is often referred to as the "molecular unit of currency" for intracellular energy transfer. When consumed in a Metabolism, metabolic process, ATP converts either to adenosine diphosphate (ADP) or to adenosine monophosphate (AMP). Other processes regenerate ATP. It is also a Precursor (chemistry), precursor to DNA and RNA, and is used as a coenzyme. An average adult human processes around 50 kilograms (about 100 mole (unit), moles) daily. From the perspective of biochemistry, ATP is classified as a nucleoside triphosphate, which indicates that it consists of three components: a nitrogenous base (adenine), the sugar ribose, and the Polyphosphate, triphosphate. Structure ATP consists of three parts: a sugar, an amine base ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Enzyme
An enzyme () is a protein that acts as a biological catalyst 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 include Ribozyme, catalytic RNA molecules, also called ribozymes. They are sometimes descr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Chorismate
Chorismic acid, more commonly known as its anionic form chorismate, is an important biochemical intermediate in plants and microorganisms. It is a precursor for: * The aromatic amino acids phenylalanine, tryptophan, and tyrosine * Indole, indole derivatives and tryptophan * 2,3-Dihydroxybenzoic acid (DHB) used for enterobactin biosynthesis * The plant hormone salicylic acid * Many alkaloids and other aromatic metabolites. * The folate precursor ''para''-aminobenzoate (pABA) * The biosynthesis of vitamin K and folate in plants and microorganisms. The name chorismic acid derives from a classical Greek word meaning "to separate", because the compound plays a role as a branch-point in aromatic amino acid biosynthesis. Biosynthesis Shikimate → shikimate-3-phosphate → 5-enolpyruvylshikimate-3-phosphate (5-''O''-(1-carboxyvinyl)-3-phosphoshikimate) : Chorismate synthase is an enzyme that catalyzes the final chemical reaction: : 5-''O''-(1-carboxyvinyl)-3-phosphoshikimate → ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
3-dehydroquinate Synthase II
3-dehydroquinate synthase II (, ''DHQ synthase II'', ''MJ1249 (gene)'', ''aroB' (gene)'') is an enzyme with systematic name ''2-amino-3,7-dideoxy-D-threo-hept-6-ulosonate:NAD+ oxidoreductase (deaminating)''. This enzyme catalyses the following chemical reaction : 2-amino-3,7-dideoxy-D-threo-hept-6-ulosonate + H2O + NAD+ \rightleftharpoons 3-dehydroquinate + NH3 + NADH + H+ The enzyme was isolated from the archaeon ''Methanocaldococcus jannaschii ''Methanocaldococcus jannaschii'' (formerly ''Methanococcus jannaschii'') is a thermophile, thermophilic methanogenic archaean in the class Methanococci. It was the first archaeon, and third organism, to have its complete genome genome sequencing ...''. References External links * {{Portal bar, Biology, border=no EC 1.4.1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
L-Aspartic-4-semialdehyde
L-Aspartic-4-semialdehyde is an α-amino acid derivative of aspartate. It is an important intermediate in the aspartate pathway, which is a metabolic pathway present in bacteria and plants. The aspartate pathway leads to the biosynthesis of a variety of amino acids from aspartate, including lysine, methionine, and threonine. Aspartate pathway The aspartate pathway is an amino acid metabolic pathway present in bacteria and plants that deal with converting aspartate to other amino acids through a series of reactions and intermediates. L-Aspartate-4-semialdehyde serves as one of the first intermediates in the pathway and as an important step of differentiation in the pathway. L-Aspartate-4-semialdehyde is synthesized by the enzyme aspartate semialdehyde dehydrogenase, which catalyzes the following reversible chemical reaction: :L-4-Aspartyl phosphate + NADPH + H+ \rightleftharpoons L-aspartate-4-semialdehyde + NADP+ + phosphate Once L-aspartate-4-semialdehyde is synthesized, th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
2-amino-3,7-dideoxy-D-threo-hept-6-ulosonate Synthase
2-amino-3,7-dideoxy-D-threo-hept-6-ulosonate synthase (, ''ADH synthase'', ''ADHS'', ''MJ0400 (gene)'') is an enzyme with systematic name ''L-aspartate 4-semialdehyde:1-deoxy-D-threo-hexo-2,5-diulose 6-phosphate methylglyoxaltransferase''. This enzyme catalyses the following chemical reaction : L-aspartate 4-semialdehyde + 1-deoxy-D-threo-hexo-2,5-diulose 6-phosphate \rightleftharpoons 2-amino-3,7-dideoxy-D-threo-hept-6-ulosonate + 2,3-dioxopropyl phosphate The enzyme plays a key role in an alternative pathway of the biosynthesis Biosynthesis, i.e., chemical synthesis occurring in biological contexts, is a term most often referring to multi-step, enzyme-Catalysis, catalyzed processes where chemical substances absorbed as nutrients (or previously converted through biosynthe ... of 3-dehydroquinate. References External links * {{Portal bar, Biology, border=no EC 2.2.1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
3-dehydroquinate Synthase
The enzyme 3-dehydroquinate synthase (EC 4.2.3.4) catalysis, catalyzes the chemical reaction :3-deoxy-D-''arabino''-hept-2-ulosonate 7-phosphate \rightleftharpoons 3-dehydroquinate + phosphate The protein uses Nicotinamide adenine dinucleotide, NAD+ to catalyze the reaction. This reaction is part of the shikimate pathway which is involved in the biosynthesis of aromatic amino acids. 3-Dehydroquinate synthase belongs to the family of lyases, to be specific those carbon-oxygen lyases acting on phosphates. This enzyme participates in phenylalanine, tyrosine, and tryptophan biosynthesis. It employs one cofactor (biochemistry), cofactor, cobalt (Co2+). Background The shikimate pathway is composed of seven steps, each catalyzed by an enzyme. The shikimate pathway is responsible for producing the precursors for aromatic amino acids, which are essential to our diets because we cannot synthesize them in our bodies. Only plants, bacteria, and microbial eukaryotes are capable of prod ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
DAHP Synthase
3-Deoxy-D-arabinoheptulosonate 7-phosphate (DAHP) synthase () is the first enzyme in a series of metabolic Chemical reaction, reactions known as the shikimate pathway, which is responsible for the biosynthesis of the amino acids phenylalanine, tyrosine, and tryptophan. Since it is the first enzyme in the shikimate pathway, it controls the amount of carbon entering the pathway. Enzyme enzyme inhibitor, inhibition is the primary method of regulating the amount of carbon entering the pathway. Forms of this enzyme differ between organisms, but can be considered DAHP synthase based upon the reaction that is catalyzed by this enzyme. In enzymology, a DAHP synthase () is an enzyme that catalysis, catalyzes the chemical reaction :phosphoenolpyruvate + D-erythrose 4-phosphate + H2O \rightleftharpoons 3-deoxy-D-arabino-hept-2-ulosonate 7-phosphate + phosphate The three substrate (biochemistry), substrates of this enzyme are phosphoenolpyruvate, D-erythrose 4-phosphate, and water, H2O, w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Erythrose-4-phosphate
Erythrose 4-phosphate is a phosphate of the simple sugar erythrose. It is an intermediate in the pentose phosphate pathway and the Calvin cycle. The enzyme transaldolase catalyzes the formation of erythrose 4-phosphate and fructose 6-phosphate from sedoheptulose 7-phosphate and glyceraldehyde 3-phosphate. This reaction is a part of the non-oxidative phase of the pentose phosphate pathway. In the Calvin cycle, the enzyme fructose-bisphosphate aldolase catalyzes the formation of sedoheptulose 1,7-bisphosphate from erythrose 4-phosphate and dihydroxyacetone phosphate. In addition, it serves as a precursor in the biosynthesis of the aromatic amino acids tyrosine, phenylalanine, and tryptophan. It is used in the first step of the shikimate pathway. At this stage, phosphoenolpyruvate and erythrose-4-phosphate react to form 3-deoxy-D-arabinoheptulosonate-7-phosphate (DAHP), in a reaction catalyzed by the enzyme DAHP synthase. : It also used in 3-hydroxy-1-aminoacetone phosphate biosy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
