Poly-a,L-lysine

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. 

When PGA or poly-a,L-lysine was irradiated with cobalt-60 7-rays in neutral 1% aqueous solution in vacuum, the viscosity fell rapidly with dose (Figure 2). This effect suggests that the molecular weight of the polymer is decreased, and confirmation was obtained for PGA by gel filtration on Sephadex G75. Whereas the unirradiated polymer (average molecular... 

The evidence is that for poly-D,L-alanine cross-linking is the predominant process for poly-a,L-lysine chain fracture is predominant, and for poly-a,L-glutamic acid cross-linking predominates below pH 4 and chain fracture above pH 4. It is possible that under all conditions studied here all three polymers undergo partial cross-linking and chain scission hence, pH could either suppress cross-linking at high pH or suppress chain fracture... 

With poly-a,L-glutamic acid, the more marked effect of pH on radiation-induced viscosity changes indicates that in this case there is probably an effect in addition to that found with poly-a,L-lysine and poly-D,L-alanine, and this probably arises from charge repulsion as discussed above. 

In recent work Tam and Rao have attached unprotected peptides directly to a third generation poly(a, -L-lysine) dendrimer [149]. As shown in Scheme 20b, the dendrimer is modified to contain eight aldehyde groups. These are then reacted with a cysteine terminated polypeptide with formation of a thiazolidine ring. The addition of the first five polypeptides occurs within 2 h at 18 °C but addition of subsequent peptide chains becomes progressively slower. After 67 h a... 

For polymer chemists it is interesting to know how well-known linear polymers can be linked with dendritic architectures and what the supramolecular consequences of this approach might be. Combination of dendrimers with linear polymers in hybrid linear-dendritic block copolymers has been employed to achieve particular self-assembly effects. Block copolymers with a linear polyethylene oxide block and dendritic polybenzylether block form large micellar structures in solution that depend on the size (i.e., the generation) of the dendritic block [10]. Amphiphilic block copolymers have been prepared by the combination of a linear, apolar polystyrene chain with a polar, hydrophilic poly(propylene imine) dendrimer [11] as well as PEO with Boc-substituted poly-a, -L-lysine dendrimers, respectively [12]. Such block copolymers form large spherical and cylindrical micelles in solution and have been described as superamphi-philes and hydra-amphiphiles , respectively. 

Oliveira ED, Hirsch SG, Spontak RJ, Gehrke SH (2003) Influence of polymer conformation on the shear modulus and morphology of polyallylamine and poly(a-L-lysine) hydrogels. Macromolecules 36 6189-6201... 

Blauer G, Alfassi ZB (1967) A comparison between poly-a, L-omithine and poly-a, L-lysine in solution the effect of a CH2 group on the side-chain on the conformation of the poly-a-amino acids. Biochim Biophys Acta 133 206-218... 

Poly(dimethyldiaHyl ammonium chloride)/human serum albumin Cationic chitosan/poly(a — L-lysine)... 

Figure 2. Change in relative viscosity of poly-a,L-glutamic add ( ) and poly-

A photochromic polymer containing azobenzene units has also been prepared by modification of a naturally occurring microbial poly(E-L-lysine) (Scheme 5, Structure IX), and investigated by means of absorption and circular dichroism spectroscopy.1431 The structure of this polymer, however, does not correspond to those of polypeptides, which are poly(amide)s of a-amino acids, and therefore the results cannot be discussed in terms of the typical polypeptide structures (a-helix, P-structure, random coil) and their standard CD spectra. 

Fig. 7 a-g Chemical structures of biohybrid homopolymer amphiphiles. a L-Cysteine-grafted polybutadiene, b Glycosylated polybutadiene, c Glycosylated poly(2-oxazoline). d V,V-l)ialkyl chitosan. e Amphiphilic poly(L-lysine). f PEGylated poly(Z-L-lysine). g Lipid-lysine dendron... 

Polystyrene-block-poly(L-lysine), polybutadiene-block-poly(L-lysine) [72], and block copolymers of polystyrene or polybutadiene with poly(carboxybenzoxy-L-lysine) [73] were also synthesized by Gallot and coworkers and evidence for lamellar assembUes were presented. Polysaccharide-block-polypeptide rod-coil systems were obtained by polymerizing the IV-carboxyanhydrides of Y -benzyl-L-glutamate from the asparagine a-amino function of carbohydrate fractions of ovomucoid (a glycoprotein extracted from hen egg white). Lamellar assembUes in concentrated solutions and in... 

Schlaad et al. reported in greater detail on the solid-state phase behavior of linear and bottle-brush shaped polystyrene-block-poly(Z-L-lysine) in a wide range of molecular weight, composition, and architectures [76]. According to earlier reports on rod-coil block copolymers with polypeptides, mainly (undulated) lamellar morphologies were observed (see Figure 21). 

PEO-fc-P(Lys) that has the side chain partially substituted with a 3-mercaptopropionyl group PEO-l)-poly( -benzyloxycarbonyl L-lysine)... 

Billot, J.P., Douy, A., and Gallot, B. (1977) Preparation, fractionation, and structure of block copolymers polystyrene-poly(carbobenzoxy-L-lysine) and polybutadiene-poly(carbobenzoxy-L-lysine). Makromolekulare Chemie-Macromolecular Chemistry and Physics, 178,1641-1650. 

Cho, C.S., Jo, B.W., Kwon, J.K., and Komoto, T. (1994) Synthesis and structural study of an ABA block copolymer consisting of poly( -benzyloxycarbonyl-L-lysine) as the a block and poly(ethylene oxide) as the B block. Macromolecular Chemistry and Physics, 195,2195—2206. 

Tu Y-L, Wang C-C, Chen C-Y (2009) Synthesis and characterization of a poly(GMA)-graft-poly(Z-L-lysine) graft copolymer with a rod-fike structure. J Polym Sci A Polym Chem 47 4655 669... 

Figure 15 Chemical stractures of (a) Poly(a,L-glutamic acid)-alkyltrimethylammon-ium cation complexes and (b) Poly(L-lysine)-aIkyl sulfate anion complexes.

The available free carboxyl groups of the DAS—HMS can be linked via a peptide bond to available primary amine groups onto highly antigenic carriers using a carbodiimide (19). The carriers used in this case were bovine semm albumin (BSA) and poly-L-lysine (molecular weight 150,000 to 300,000). The... 

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