Glutamic acid chemical structure

The side chains of the 20 different amino acids listed in Panel 1.1 (pp. 6-7) have very different chemical properties and are utilized for a wide variety of biological functions. However, their chemical versatility is not unlimited, and for some functions metal atoms are more suitable and more efficient. Electron-transfer reactions are an important example. Fortunately the side chains of histidine, cysteine, aspartic acid, and glutamic acid are excellent metal ligands, and a fairly large number of proteins have recruited metal atoms as intrinsic parts of their structures among the frequently used metals are iron, zinc, magnesium, and calcium. Several metallo proteins are discussed in detail in later chapters and it suffices here to mention briefly a few examples of iron and zinc proteins. 

Prior to these structural studies, work using chemically modified proteins had shown the requirement for at least four histidine ligands per subunit together with a glutamic acid residue and Tyr-109 (Tyr-114 in met). The most recent X-ray work has eliminated the possibility that Tyr-109 is a ligand, a possibility proposed in earlier X-ray work. Other work on chemical modification of residues has been reviewed.1277... 

The synthetic polyamino acids are convenient models for chemical studies of proteins since they have the extended polypeptide structure of the proteins but are free from the complications which arise in the proteins from the large number of different side chains. The work described here has been confined to the water-soluble polyamino acids poly-D,L-alanine (PDLA), poly-a,L-glutamic acid (PGA), poly-a,D-glutamic acid, and poly-a,L-lysine, and the polyimino acid, poly-L-proline. 

Scheme 3 Chemical structure of poly(L-glutamic acid) modified with 4-amino-azobenzene (III), and 4-amino-azobenzene-4 -sul-fonic acid sodium salt (IV).

Recently, the difference in structure and chemical reactivity between 2-D racemic and enantiomorphous crystallites has been used to generate enan-tiopure homochiral oligopeptides from non-racemic mixtures of amphiphilic a-amino acid NCAs. The racemic N"-carboxyanhydridc of y-slcaryl-glutamic acid (Cis-Glu-NCA) self-assembles on water to form racemic 2-D crystallites (Fig. 16a,b), as proved by GIXD. 

Figure 3. Structure of peptide and isopeptide bonds resulting from covalent attachment of amino acids to proteins by chemical methods. In isopeptide bond formation Rt = -CH2- or -CH2CH2- of aspartic or glutamic acid and R2 = -(CH2)n- of lysine.

Monosodium glutamate (MSG) is the sodium salt of glutamic acid. The flavor-enhancing property is not limited to MSG. Similar taste properties are found in the L-forms of q-amino dicarboxylates with four to seven carbon atoms. The intensity of flavor is related to the chemical structure of these compounds. Other amino acids that have similar taste properties are the salts of ibotenic acid, tricholomic acid, and L-thean-ine. 

Glutamic acid, 19 catabolism, 428 chemical structure, 20 plasma conocntraticin, 465 solubility, 2)6 Glutaminase, 441, 443 Glutamine, 19... 

Subramanian, G. Hjelm, R.P. Deming, T.J. Smith, G.S. Li, Y. Safinya, C.R. Structure of complexes of cationic lipids and poly(glutamic acid) polypeptides a pinched lamellar phase. Journal of the American Chemical Society 2000, 122, 26-35. 

The peptide moiety of wax D fractions of human strains seems to be necessary for the activity of these fractions as immunological adjuvants (see p. 235) this may be due to the close chemical similarity between the structure of the water-soluble portion of wax D and the cell wall of Mycobacteria, since the latter contains the same three amino acids (alanine, glutamic acid, and a, c-diaminopimelic acid) and the same sugars (arabinose, mannose, galactose, and aminohexoses). Wax D of human strains might be considered to be a monomer of the cell wall, heavily esterified with mycolic acid. 

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