Glutamic acid properties

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. 

Glutamic acid, structure and properties of, 1019 Glutamine, structure and properties of, 1018... 

POLY(AMINO acids). Both anionic [e.g., poly(L-aspartic acid) and poly(glutamic acid)] and cationic [e.g., poly[L-lysine)] poly(amino acids) have been suggested as potential drug carriers. Poly(L-lysine) is a homopolymer cosisting of repeating units of L-lysine. It exhibits some affinity for cancer cells and possesses antimicrobial and antiviral properties. It also shows... 

E Pefferkorn, A Schmitt, R Varoqui. Helix-coil transition of poly(a,L-glutamic acid) at an interface Correlation with static and dynamic membrane properties. Biopolymers 21 1451-1463, 1982. 

More than 36 years ago, the pH-induced cooperative transitions in CD spectra and other physical properties of poly-L-glutamic acid (PGA) and poly-L-lysine (PL) were reported and taken to correspond to a... 

Kang HS, Park SH, Lee YG et al (2007) Polyelectrolyte complex hydrogel composed of chitosan and poly(y-glutamic acid) for biological application Preparation, physical properties, and cytocompatibility. J Appl Polym Sci 103 386-394... 

A series of new amino acid derivatives having pendant nucleic acid bases was prepared by the reaction of L-lysine and L-glutamic acid with the nucleic acid bases. These amino acids were further polymerized by using the N-carboxyamino acid anhydride ( NCA ) method. Alternatively, the nucleic acid base substituted poly-L-lysines were also prepared by using polymer reactions which include the reaction of carboxyethyl derivatives of the bases onto poly-L-lysine. Physico-chemical properties of the polymers obtained were given. 

Higashi N, Shosu T, Koga T, Niwa M, Tanigawa T (2006) pH-responsive, self-assembling nanoparticle from a fullerene-tagged poly(L-glutamic acid) and its superoxide dismutase mimetic property. J. Colloid Interface Sci. 298 118-123. 

The functionalization of folded motifs is based on an understanding of secondary and tertiary structures (Fig. 2) and must take into account the relative positions of the residues, their rotamer populations and possible interactions with residues that do not form part of the site. For example, glutamic acid in position i has a strong propensity for salt-bridge formation, and thus reduced reactivity, if there is a Lys residue available i-4 in the sequence, but the probabihty is much less if the base is i-3 [60]. Fortunately, there is a wealth of structural information on the structural properties of the common amino acids from studies of natural proteins that provides considerable support for the design of new proteins. The naturally occurring amino acids have so far been used to construct reactive sites for catalysis [11-13], metal- and heme-binding sites [14,15,19,21,22] and for the site-selective functionalization of folded proteins [24,25]. 

The main genera responsible for freshwater toxic blooms are Microcystis, Anabaena, Aphanizomenon and Oscillatoria. Toxins produced include 1. anatoxins, alkaloids and peptides of Anabaena 2. the peptide microcystin and related peptides of Microcystis 3. aphantoxins, compounds of Aphanizomenon with properties similar to some paralytic shellfish poisons. Properties of Oscillatoria toxin suggest they are peptides similar to those of Microcystis. Microcystis toxins are peptides (M.W. approx. 1200) which contain three invariant D-amino acids, alanine, erythro-3-methyl aspartic and glutamic acids, two variant L-amino acids, N-methyl dehydro alanine and a 3-amino acid. Individual toxic strains have one or more multiples of this peptide toxin. The one anatoxin characterized is a bicylic secondary amine called anatoxin-a (M.W. 165). The aphantoxin isolated in our laboratory contains two main toxic fractions. On TLC and HPLC the fractions have the same characteristics as saxitoxin and neosaxitoxin. 

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