Aspartic and Glutamic Acids

The higher esterification rate of P- and y-carboxyl groups can be used for selective reactions. On the other hand the P- and y-carboxyl groups are more rapidly hydrolyzed in acid-catalyzed hydrolysis since protonation is facilitated by having the ammonium group further away from the carboxyl group. Alkali-catalyzed hydrolysis of methyl or ethyl esters of aspartic or glutamic acids bound to peptides can result in the formation of isopeptides. 

Decarboxylation of glutamic acid yields y-amino-butyric acid. This compound, which also occurs in wine (cf. 20.2.6.9), tastes sour and produces a dry feeling in the mouth at concentrations above its recognition threshold (0.02 mmol/1). 

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Some ammo acids have side chains that bear acidic or basic groups As Table 27 3 indicates these ammo acids are characterized by three values The third pK reflects the nature of the side chain Acidic ammo acids (aspartic and glutamic acid) have acidic side chains basic ammo acids (lysine arginine and histidine) have basic side chains The isoelectric points of the ammo acids m Table 27 3 are midway between the pK values of the zwitterion and its conjugate acid Take two examples aspartic acid and lysine Aspartic acid has an acidic side chain and a pi of 2 77 Lysine has a basic side chain and a pi of 9 74... 

Cyclic anhydddes aie formed readily from Al-protected aspartic and glutamic acids. 

Oxazolidines are prepared to allow selective protection of the ct- or aj-C02H groups in aspartic and glutamic acids. 

The importance of Heinrich Ritthausen s fundamental studies, 1862 to 1899, on analytical procedures for the determination of amino acids in proteins has been emphasized in the biographical sketches which have been presented by Osborne (210), Vickery (289), and Chibnall (47). It is of particular interest to note here the prediction made by Ritt-hausen about 1870 that the amino acid composition would prove to be the most adequate basis for the characterization of proteins. Ritthausen and Kreusler (230) were the first, in 1871, to determine amino acids derived from proteins, and some of the values which they found for aspartic and glutamic acids are given in Table III (cited by Chibnall, 47, and Vickery, 286). 

The low yields of aspartic and glutamic acid which limit our research interpretations are most likely due to some aspect of laboratory method... 

Sapse, A.-M., M. Mezei, D. C. Jain, and C. Unson. 1994. Ab Initio Study of Aspartic and Glutamic Acid Supplementary Evidence for Structural Requirements at Postition 9 for Glucagon Activity. J. Mol. Struct. (Theochem) 306, 225-233. 

Most proteins contain an abundance of carboxylic acid groups from C-terminal functionalities and aspartic and glutamic acid side chains. These groups are readily modified with bis-hydrazide compounds to yield useful hydrazide-activated derivatives. Both carbohydrazide and adipic acid dihydrazide have been employed in forming these modifications using the carbodi-imide reaction (Wilchek and Bayer, 1987). 

The relationship of the dicarboxylic amino acids, aspartic and glutamic acids to this process has also been studied (106). This investigation has been facilitated by a quantitative method for the codetermination (23) of the dehydrogenation indicator, resazurin, and its reduction product, resorufin. The wood destroying molds used were Trameles cinnabarina and Lentinus lepideus. 

Aspartic and glutamic acids are themselves negatively charged under physiological conditions. This allows them to chelate certain metal ions, and also to markedly influence the conformation adopted by polypeptide chains in which they are found. 

Several of the 20 amino acids that constitute the building blocks of proteins exhibit charged side chains. At pH 7.0, aspartic and glutamic acids have overall negatively charged acidic... 

A series of 1-aminoalkanediphosphonic acids has been reported by the treatment of the N-phenylthiourea derivatives of a>-diethoxyphos-phinoylaldehydes with triphenyl phosphite.343 This constitutes an approach toward the analogues of aspartic and glutamic acid in which both carboxylate sites have been replaced by phosphonic acid functions. A similar approach has also been reported to be of use for the preparation of (diphenyl ester) phosphonate analogues of ornithine, lysine, and homolysine.344345... 

Oleksyszyn, J., Gruszecka, E., Kafarski, P., and Mastalerz, P., New phosphonic analogs of aspartic and glutamic acid by aminoalkylation of trivalent phosphorus chlorides with ethyl acetoacetate, ethyl levulinate and benzyl carbamate, Monatsh. Chem., 113, 59, 1982. 

P2. Pollack, R. L., and Eades, C. H., Glucuronic acid conjugates of aspartic and glutamic acids in urine. Science 119, 510-511 (1954). 

X Huang, X Luo, Y Roupioz, JW Keillor. Controlled regioselective anilide formation from aspartic and glutamic acid anhydrides. J Org Chem 62, 8821, 1997. 

Sowden et al. [4] also did detailed amino acid and amino sugar analyses of the soils from the different dimatic regions. The following amino acids were determined acidic amino acids aspartic and glutamic acids basic amino acids arginine, histidine, lysine and ornithine neutral amino adds, phenylalanine, tyrosine, glycine, alanine, valine, leudne, isoleudne, serine, threonine, proline and hydroxyproline ... 

Aspartic and glutamic acids were not retained in a buffer solution without a counter-ion however, these acids were retained by the addition of octyl sulfate to the eluent, as seen in Figure 4.12. These amino acids can form a complex with copper ions and will be retained on the stationary phase. The addition of both a counter-ion and copper ions further increased the retention and made possible... 

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