Tyrosine-containing poly

Abbreviations—PSA, poly(sebacic acid) PAA, poly(adipic acid) P(CPH), 1,3 bistp-carboxyphenoxyhexane) P(CPP-SA), poly(1,3 bis(p-carboxyphenoxypropane-sebacic acid) copolymer PtA, poly(o,L-lactide) Poly(TMA-Tyr SA CPP), tyrosine-containing poly(anhydride-co-imide) P(RA-SA), poly(ricinoleic acid-sebacic acid) copolymer PBSAM, /V,A"-bis(L-alanine)-sebacoylamide MSA, methacrylated sebacic acid MCPH, methacrylated 1,3... 

M. Chiba, J. Hanes, R. Langer, Controlled protein delivery from biodegradable tyrosine-containing poly (anhydride-co-imide) microspheres, Biomaterials 18 (1997) 893-901. 

Tyrosine-containing poly(DTR-PEG ethers) (Fig. 1.25) these polymers are synthesized by copolymerization of tyrosine-derived monomers and methylsulfone-activated PEG. 

A polynucleoside with an unnatural polymeric backbone was synthesized by SBP-catalyzed oxidative polymerization of thymidine 5 -p-hydroxyphenylacetate. Chemoenzymafic synthesis of a new class of poly(amino acid), poly(tyrosine) containing no peptide bonds, was achieved by the peroxidase-catalyzed oxidative polymerization of tyrosine ethyl esters, followed by alkaline hydrolysis. Amphiphile higher alkyl ester derivatives were also polymerized in... 

Tyrosine-containing peptides Polyacrylamide poly(ethylene glycol) macroporous packing Acetonitrile-10 mM Tris, 15 mM boric acid, pH 8.2 (47 53) 250 mm x 100 pm i.d. 205 mm packed length 36... 

S. Mallakpour, F. Zeraatpisheh, M.R. Sabzalian, Construction, characterization and biological activity of chiral and thermally stable nanostructured poly(ester-imide)s as tyrosine-containing pseudo-poly(amino acid)s, J. Polym. Environ. 20 (2012) 117-123. 

Poly[N-(2-hydroxypropyl)methacrylamide] is another polymer developed as a prospective plasma expander and as such its rate of elimination from the bloodstream was of mterest. As mentioned in section 2, experiments were carried out using [ C]polymer and the results obtained show that clearance is clearly related to the molecular weight of the polymer. Recently, by using N-(2-hydroxypropyl)-methacrylamide copolymers whose tyrosine-containing side chams were labelled with [ I]iodide it has been shown that the pattern of blood clearance from rats is consistent with that reported for a similar molecular weight distribution of I-labelled PVP, i.e. these data show that N-(2-hydroxypropyl)methacrylamide copolymers are captured, like polyvmylpyrrolidone, non-selectively in vivo by fluid-phase pinocytosis. 

Since the oxidative polymerization of phenols is the industrial process used to produce poly(phenyleneoxide)s (Scheme 4), the application of polymer catalysts may well be of interest. Furthermore, enzymic, oxidative polymerization of phenols is an important pathway in biosynthesis. For example, black pigment of animal kingdom "melanin" is the polymeric product of 2,6-dihydroxyindole which is the oxidative product of tyrosine, catalyzed by copper enzyme "tyrosinase". In plants "lignin" is the natural polymer of phenols, such as coniferyl alcohol 2 and sinapyl alcohol 3. Tyrosinase contains four Cu ions in cataly-tically active site which are considered to act cooperatively. These Cu ions are presumed to be surrounded by the non-polar apoprotein, and their reactivities in substitution and redox reactions are controlled by the environmental protein. 

Earlier studies include those of Merrifield and Wooley (i27) and of Katchalski et al. (128). They prepared poly-L-histidine and its copolymers with other amino acids and showed them to be active in the hydrolysis of PNPA. Noguchi and Saito prepared poly-L-histidine, its copolymers with other amino acid residue (glutamic acid 2, aspartic acid 3, serine 4, alanine 5, cystein 6, lysine 7, e-aminocaproic acid S, and tyrosine 9), and various dipeptides containing the histidyl residue 1), (129,130). The... 

Poliovirus RNA in many respects looks like a typical eukaryotic mRNA with a polyadenylated 30 tail and a protected 50 terminus. However, the poly (A) tail is not added by the action of poly (A) polymerase, but instead is encoded in the viral genome. In addition, the 50 end does not contain a 7-methylguanosine cap, but rather a covalently attached viral protein called VPg that has a phosphodiester linkage between a tyrosine residue in VPg and a uridine in the viral RNA. 

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-... 

Mallakpour S, Dinar M. Insertion of novel optically active poly(amide-imide) chains containing pyromellitoyl-bis-l-phenylalanine linkages into the nanolayered silicates modified with 1-tyrosine through solution intercalation. Polymer 2011 52(12) 2514-23. 

Aromatic biosynthesis, aromatizatioa biosynthesis of compounds containing the benzene ring system. The most important mechanisms are 1. the shi-kimate/chorismate pathway, in which the aromatic amino acids, L-phenylalanine, L-tyrosine and L-trypto-phan, 4-hydroxybenzoic acid (precursor of ubiquinone), 4-aminobenzoie acid (precursor of folic acid) and the phenylpropanes, including components of lignin, cinnamic acid derivatives and flavonoids are synthesized and 2. the polyketide pathway (see Polyke-tides) in which acetate molecules are condensed and aromatic compounds (e.g. 6-methylsalicylic acid) are synthesized via poly-fl-keto acids. Biosynthesis of flavonoids (e.g. anthocyanidins) can occur by either pathway. 

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