Polypeptides and Polyamides

Folda, T., Gros, L. and Ringsdorf, H. (1982). Formation of oriented polypeptides and polyamides in monolayers and liposomes. Macromolecular Rapid Communications, 3, 167-74. 

In the literature a majority of the publications involving enzyme-catalyzed synthesis of polypeptides and polyamides use proteases and related proteolytic enzymes. The data indicate that proteases are good catalysts for the synthesis of oligomers. For high-molecular-weight polymers, the use of protease is more difficult and less reported. 

Amide Polypeptides and polyamides such as nylon Peptide amide bond cleavage, N-alkylation of the amide bonds, imidoester reaction [165,182]... 

N. Yamazaki, F. Higasi, J. Kawataba, Studies on reactions of the N-phosphonium salts of pyridines. XI. Preparation of polypeptides and polyamides by means of triarylphosphites in pyridine, J. Polym. Sci. Polym. Chem. Edition 12 (9) (1974) 2149-2154. 

Yamazaki N, Higashi F and Kawabata J (1974) Studies on Reactions of the N-phos-phonium salt of p5T idines. XL Preparation of polypeptides and polyamides by means... 

F. Chen and W. V. Chang. Applicability study of a new acid base interaction model in polypeptides and polyamides. Langmuir 1, 1991, 2401. 

A wide range of polymer networks are constructed in this manner. Poly(vinyltrichloacetate) was used as the coinitiator with styrene, MMA and chloroprene as cross-linking units. Polycarbonates, polystyrene, N-haloge-nated polyamide, polypeptides, and cellulose acetate, suitably functionalized, have been used as a coinitiator... 

These are also called polyamides or polypeptides. The latter term is often used by biochemists to denote oligomers or relatively low molecular weight proteins. (Note the structural similarities and differences between proteins and polyamides—nylons (Section 4.8).)... 

The stereochemistry of step polymerization is considered now. Bond formation during step polymerization almost never results in the formation of a stereocenter. For example, neither the ester nor the amide groups in polyesters and polyamides, respectively, possess stereocenters. Stereoregular polymers are possible when there is a chiral stereocenter in the monomer(s) [Oishi and Kawakami, 2000 Orgueira and Varela, 2001 Vanhaecht et al., 2001], An example would be the polymerization of (R) or (S)-H2NCHRCOOH. Naturally occurring polypeptides are stereoregular polymers formed from optically active a-amino acids. 

Polypeptide and protein Synthetic polymers Polyamide Polyesters... 

Hydrolytic degradation is especially important in polymers with hydrolyzable links between the CRUs. Thus, polyesters can be saponified to yield the starting materials from which they were formed. Acetal links in synthetic polymers such as polyoxymethylene, or in natural polymers such as cellulose, can be hydrolyzed with acids. However, the resistance to hydrolysis depends very much on the structure of the polymer for example, polyesters of terephthalic acid are very difficult to hydrolyze while aliphatic polyesters are generally easily hydrolyzed. Polyamides are normally much more resistant to hydrolysis than polyesters they may be cleaved by the methods usually employed for polypeptides and proteins. 

A group of semicrystalline thermoplastics containing the amide group (—NHCO-) in the main chain, resulting from polycondensation of either a,o)-lactam or a diacid with a diamine. Natural polyamides, polypeptides, and synthetic polyamides belong to this family. 

Hydrogen bonding is particularly important in polymers and copolymers containing the following functional groups amide (polypeptides, proteins, polyamides), urethane (polyurethanes), hydroxyl (cellulose, polyvinyl alcohol), and carboxyl (polyacrylic acid). 

The pretransition phenomena can also result in the appearance of a more gently sloping segment of curve t](c), as obsoved in [88, 89]. The increase w decrease in the rate of the increase in dependence tiCc) when c c is apparently determined by the morphology of the fluctuation formations when c c, which can be spherulitic in solutions of aromatic polyamides (indicated in the circles in Fig. 9.19) and fibrillar in solutions of polypeptides and polyisocyanates. 

Proteins have their monomers bonded to each other via peptide links (also called amide links in synthetic polymers such as nylons). This means that polypeptides and proteins are types of polyamide. 

Studies of microphase separation have been made on many regular block copolymers containing crystallizable blocks. The types of crystallizable blocks which have been examined include poly-ethers, " polyamides/ " polypeptides and polyesters. 

Figures 13.54 thru 13.56 have been singled for special mention because of the unusual nature of the applications presented. Because peptides are also polyamides and because we routinely run polyamides using hexafluoro-2-pro-panol (FIFIP) as solvent, a modified polypeptide, poly (leucine-comethyl glutamate), was run in FIFIP. Figure 13.54 shows the results and suggests that modified HFIP might well prove to be a good solvent for at least some polypeptide purifications/characterizations. Figure 13.55 demonstrates the use of modi-...

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