Aspartic acid naturally occurring

L-aspartic acid, also known as c-asparagic add, L-aminosuccinic acid, and 2-aminobutanedioic acid (denoted Asp or D), is a nonessential, acidic amino acid, as can be seen from the chemical structure (Fig. 15.3). On reviewing the literature, it becomes evident that Asp was discovered by Plisson in 1827, and it was obtained by simply boiling asparagine with a base (http // www.inchem.org/documents/icsc/icsc/eicsl439.htm). Aspartic acid naturally occurs in Leavo (L-form) and/or Dextro (o-form). 

The third mechanism is represented by nonmodular one-step peptide synthesis. Enzymes belonging to this group catalyze the biosynthesis of poly(amino acids). Naturally occurring poly(amino acids) comprise cyanophy-cin [multi-L-arginyl-poly-(L-aspartic acid) cyanophycin granule polypeptide, (CGP)], (poly-(e-lysine) (PL), and poly-(y-glutamate) (PGA). As a consequence of non-ribosomal biosynthesis these peptides reveal a polydisperse mass distribution. 

The naturally occurring substance is L-aspartic acid. One of the acidic-amino acids obtained by the hydrolysis of proteins. 

Fumaric acid occurs naturally in many plants and is named after Fumaria officinalis, a climbing aimual plant, from which it was first isolated. It is also known as (E)-2-butenedioic acid, aHomaleic acid, boletic acid, Hchenic acid, or /n j -l,2-ethylenedicarboxylic acid. It is used as a food acidulant and as a raw material in the manufacture of unsaturated polyester resins, quick-setting inks, furniture lacquers, paper sizing chemicals, and aspartic acid [56-84-8]. 

The noteworthy successes of a relevant model study12 provided the foundation for Merck s thienamycin syntheses. In the first approach (see Schemes 2 and 3), the journey to the natural product commences from a readily available derivative of aspartic acid this route furnishes thienamycin in its naturally occurring enantiomeric form, and is noted for its convergency. During the course of this elegant synthesis, an equally impressive path to thienamycin was under parallel development (see Schemes 4 and 5). This operationally simple route is very efficient (>10% overall yield), and is well suited for the production of racemic thienamycin on a commercial scale.. x... 

Unfortunately, the modification of the side chain is not a generally applicable approach. Among the major, naturally occurring amino acids, only L-lysine has a chemically reactive side chain that would be as readily available for chemical modification as the side chain of glutamic or aspartic acid. Since, however, poly (L-lysine) is known to be toxic (10), its derivatives cannot be candidates for generally applicable biomaterials. Thus, most of the poly(amino acids) that have so far been suggested as biomaterials are derivatives of gluteunic or aspartic acid or copolymers of such derivatives with leucine, methionine, or a limited number of additional amino acids (11). 

The discovery of homochirality on a planet such as Mars could be an excellent biomarker and strengthen the argument for life on Mars. With an EE in the solar nebula there should be an EE on the surface of Mars of order 9 per cent but remains of ancient life on Mars would show a greater excess. The interchange of enantiomers occurs naturally in a process called racemisation and for the most labile amino acid, aspartic acid, the half-life for the racemisation is 800 years at 300 K in 800 years, half of the non-biotic aspartic acid would racemise and the EE would go to zero. In dry conditions, however, the half-life is much longer, perhaps as large as 5 x 104 years at 300 K. Extrapolation of the racemisation rate to 215 K, the equatorial temperature of Mars, extends the half-life further to 3 x 1012 years and to 1027 years at 150 K, Martian polar temperatures. Hence, discovery of a considerable EE in the Martian soil would be a strong indicator of ancient Martian life. 

The interaction with both synthetic and naturally occurring amino acids has been studied extensively glycine (138, 173, 219-221), a-(173, 219) and /3-alanine (138, 220), sarcosine (219), serine (222), aspartic acid (138, 173, 222-226), asparagine (222), threonine (222), proline (219), hydroxyproline (219), glutamic acid (138, 222-225), glutamine (222), valine (219, 227), norvaline (219), methionine (222, 226), histidine (228, 229), isoleucine (219), leucine (219, 230), norleu-cine (219), lysine (222), arginine (222), histidine methyl ester (228), phenylalanine (138, 222), tyrosine (222), 2-amino-3-(3,4-dihydroxy-phenyl jpropanoic acid (DOPA) (222), tryptophan (222), aminoiso-butyric acid (219), 2-aminobutyric acid (219,231), citrulline (222), and ornithine (222). 

N 072 "Helix-Coil Stability Constants for the Naturally Occurring Amino Acids in Water. 16. Aspartic Acid Parameters from Random... 

From the ring opening of p-lactams by amines and a-amino acids, p-amino amides and fi-amino acid derived peptides are generated. These structures are of interest because of their presence in several naturally occurring macrocyclic compounds [82, 83]. One example of the latter is the p-hydroxy aspartic acid derived tripeptide 45 found in the macrocyclic peptide lactone antibiotic lysobactin 40 [84], Fig. 4. 

The sweetener aspartame was discovered in 1965 and approved by the FDA in 1981. It is the methyl ester of a dipeptide formed from the amino acids aspartic acid and phenylalanine. Because both of these amino acids occur naturally and arc part of nearly every protein, there is much less reason to be concerned about the health effects of this compound. Nevertheless, it has been extensively tested. Aspartame is about 180 times sweeter than sucrose, so the amount that is needed to sweeten a can of a soft drink, for example, is so small that it contributes only negligible calories to the diet. In addition, the taste profile of aspartame is much closer to sugar than is that of saccharin. Aspartame, sold under the brand name NutraSweet, has been an enormous financial success. Sucralose (Splenda) is prepared from sucrose by replacing some of the hydroxy groups with chlorines. Its taste closely resembles sucrose, but it is about 600 times sweeter. Acesulfame K (Sunett, Sweet One) is about 200 times sweeter than sucrose. It is quite stable to heat, so it is potentially very useful in baked goods. 

Chromodulin is a naturally occurring oligopeptide composed of glycine, cysteine, aspartate, and glutamate with the carboxylates comprising more than half of the total amino acid residues. The lack of a published sequence... 

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