Tyrosine glutamic acid polypeptide

In summary, protein molecules may contain up to nine amino acids that are readily derivatizable at their side chains aspartic acid, glutamic acid, lysine, arginine, cysteine, histidine, tyrosine, methionine, and tryptophan. These nine residues contain eight principal functional groups with sufficient reactivity for modification reactions primary amines, carboxylates, sulfhydryls (or disulfides), thioethers, imidazolyls, gua-nidinyl groups, and phenolic and indolyl rings. All of these side chain functional groups in addition to the N-terminal a-amino and the C-terminal a-carboxylate form the full complement of polypeptide reactivity within proteins (Fig. 12). 

Pinna nobilis tropomyosin contains no proline (Bailey, 1957), which is consistent with a helical molecule. As might be expected from the study of a 5% copolymer of L-tyrosine with L-glutamic acid (see Section III, F), the presence of small amounts of tyrosine and histidine in this protein has no appreciable rotatory effect. This protein contains relatively large amounts of amino acids that do form standard helical polypeptides—glutamic acid, 21 % lysine, 8% alanine, 12% and leucine, 12.5 %—but it also has 4 % valine, 6 % serine, and 13 % aspartic acid. If these residues behaved as they and their analogues appear to do in synthetic polypeptides, either pre-... 

Ptaasin. Poisonous agglutinin from beans. A polypeptide compoeed of glutamic acid, aspartic acid, serine, alanine, tyrosine, lysine and arginine Piekarski, Dissertationes Pharm. , 255 (1957), C.A. 52, 6456i (1958). Prepm Wien-haus, Biochem. Z. 18, 228 (1909), C.A. 3, 2471 (1909) Piekarski, loc. dr. 

The internal structure of the cross-linked synthetic polypeptides is maintained by heat-stable, covalent bonding between the cross-linked amino acid side chains and by heat-labile, noncovalent side chain interactions between glutamic acid and lysine residues (electrostatic) and between tyrosine residues (nonpolar). The stability of the spatial structure of a polymer depends upon the relative proportion of covalent and noncovalent bonding that it contains and increases as the number of cross-links increases. According to the current theories of protein structure, the charged amino acid residues would be arrayed on the surface of the molecule, and the tyrosine residues would be internally placed and thus interact to give a hypochromic effect. Am(6)-poly Glu52Lys33Tyr15 (No. 3B) (Fr. 1) displays such an effect, and the molar extinction coefficient of the cross-linked derivative is 25% lower than that of the parent polymer. This hypo-... 

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