Pentose, 2-amino-2-deoxy 5-phosphate

Calcium bis(2-amino-2,3,4-trideoxy-L-gZycero-pentarate) (calcium di-L-glutamate), tetrahydrate D-Arabinono-1,4-lactone Calcium L-arabinonate, pentahydrate Strontium L-arabinonate, pentahydrate Barium D-ribose 5-phosphate, pentahydrate 2-Deoxy-D-en/thro-pentose j8-DL-Arabinopyranose... 

In a very imaginative piece of research Frost and coworkers have developed a plasmid-based method for synthesizing aromatic amino acids, by incorporating the genes that code for the enzymes that perform the series of conversions from D-fructose-6-phosphate to D-erythrose-4-phosphate to 3-deoxy-D-arabinoheptulosonic acid-7-phos-phate (DAHP) near each other on a plasmid that can be transformed in E. coli. The enzymes are the thiamin diphosphate-dependent enzyme transketolase in the nonoxida-tive pentose shunt and DAHP synthase. The DAHP is then converted to the cyclic dehydroquinate, a precursor to all aromatic amino acids L-Tyr, L-Phe and L-Trp165,166 (equation 27). 

Phenolic compounds include a wide range of secondary metabolites that are biosynthesised from carbohydrates through the shikimate pathway [14]. This is the biosynthetic route to the aromatic amino acids, phenylalanine, tyrosine, and tryptophan, and only occurs in microorganisms and plants. In the first step, the glycolytic intermediate phosphoenol pyruvate and the pentose phosphate intermediate erythrose-4-phosphate are condensed to 3-deoxy-D-arabino-heptulosonate 7-phosphate (DAHP), a step catalysed by DAHP synthase. Intermediates of the shikimate pathway are 3-dehydroquinate, shikimate, and chorismate (Fig. 1). Phenylalanine is biosynthesised from chorismate, and from phenylalanine all the phenylpropanoids. Quinate is produced from 3-dehydroquinate and incorporated into chlorogenic and isochlorogenic acids (caffeoyl quinic acids) by combination with caffeic acid. Gallic acid is produced from shikimate. 

Nature of monomer Compound molecules consisting of nitrogen base, pentose and phosphate. Simple molecules a-amino acids Simple molecules glycoses and derivatives (deoxy, N-acetylamino, and carboxyl)... 

The well-known cytoplasmic shikimate pathway is important to aromatic amino acid synthesis. It takes a long metabolic pathway to reach to an aromatic amino acid from D-glucose. Two metabolic intermediates, phosphoenolpymvate from the glycolytic pathway and D-erythrose-4-phosphate from the pentose-phosphate pathway, must combine to form 3-deoxy-7-phospho-D-arabinoheptulosonate before formation of 3-dehydroquinate (Fig. 13.4). Thus, there are still several barriers difficult to overcome in the already existing technologies of shikimate fermentation from D-glucose (Draths et al. 1999). 

Non- oxidative branch Pentose-5 -Phosphates Ribose-5-P 2 deoxy ribose-5-P 5 -phosphoribosyl-1 -pyrophosphate (PRPP) i) Structural components of nucleotides a. Basal structural component of RNA b. Basal structural component of DNA c. Precursor of both de novo and salvage synthesis of nucleotides ii) Intermediate products of purine metabolism and act as precursor molecules of cofactors, e g., riboflavin, flavin mononucleotide (FMN), flavin adenine di nucleotide (FAD) iii) Precursor of the amino acid. Histidine. 

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