Polymers and Polypeptides

X. Kong and S.A. Jenekhe, Block copolymers containing conjugated polymer and polypeptide sequences synthesis and self-assembly of electroactive and photoactive nanostructures, Macromolecules, 37 8180-8183, 2004. 

Over the years, modeling of carbohydrates has emphasized intramolecular rather than intermolecular structures. The same holds true in the study of synthetic polymers and polypeptides. Only one such study for carbohydrates comes to mind (1) where the unit cell dimensions and symmetry were not used. Even there, a volume constraint was used, limiting the possible structures. When such constraints are used, one does not obtain an explanation for why the crystal structure is the stable form. 

Commonly employed water-insoluble supports for the covalent attachment of enzymes include synthetic supports such as acrylamide-based polymers, maleic anhydride-based polymers, methacrylic acid-based polymers, styrene-based polymers, and polypeptides, and natural supports such as agarose (Sepharose), cellulose, dextran (Sephadex), glass, and starch (Zaborsky, 1973). 

For more complicated chains such as cellulose derivatives, diene polymers and polypeptides, the factor a may be defined in the more general manner. 

Natural polymers include RNA and DNA that are so important in genes and life processes. In fact, messenger RNA is what makes possible proteins, peptides, and enzymes. Enzymes do the chemistiy inside living organisms and peptides make up some of the most interesting stmctural components of skin, hair, and even the horns of rhinos. Other natural polymers include polysaccharides (sugar polymers) and polypeptides like silk, keratin, and hair. Natural mbber is a natural polymer, made from just carbon and hydrogen. 

From monomers of natural origin as amino acids to purely synthetic atropic monomers or those with two chiral centers and from polyhydrocarbons to polyelectrolytes, com-plexing polymers and polypeptides the list is long and is further lengthened by the chemical transformations of the polymers obtained. During these investigations new monomers have been synthesized and model molecules, dimers, and oligomers were necessary to perform physicochemical and spectral studies. 

The major disadvantage of solid-phase peptide synthesis is the fact that ail the by-products attached to the resin can only be removed at the final stages of synthesis. Another problem is the relatively low local concentration of peptide which can be obtained on the polymer, and this limits the turnover of all other educts. Preparation of large quantities (> 1 g) is therefore difficult. Thirdly, the racemization-safe methods for acid activation, e.g. with azides, are too mild (= slow) for solid-phase synthesis. For these reasons the convenient Menifield procedures are quite generally used for syntheses of small peptides, whereas for larger polypeptides many research groups adhere to classic solution methods and purification after each condensation step (F.M. Finn, 1976). 

Gelatin stmctures have been studied with the aid of an electron microscope (23). The stmcture of the gel is a combination of fine and coarse interchain networks the ratio depends on the temperature during the polymer-polymer and polymer-solvent interaction lea ding to bond formation. The rigidity of the gel is approximately proportional to the square of the gelatin concentration. Crystallites, indicated by x-ray diffraction pattern, are beUeved to be at the junctions of the polypeptide chains (24). 

Growing ot a polypeptide chain by attachment ot the first aminoadd to an insoluble polymer and attaching successively amirx>acids At the end cleavage of the peptide from the polymer... 

With the exception of very large systems, e.g., polymer strands (Chapter 18) and polypeptides and polynucleotides (Chapter 16), all calculations have been carried out using ab initio Hartree-Fock theory with the 3-21G basis seF. The perfomance of this technique with regard to the calculation of geometries, relative energies, dipole moments and vibrational frequencies has been extensively documented. ... 

LC polyesters belong to the class of thermotropic main-chain LCPs, which also comprises polymers such as polycarbonates, polyethers, polyphenylenes, polyester-imides, polymers containing azo- or azo V-oxide linking groups, some cellulose derivatives, and polypeptides such as po 1 y (y - be n zy 1 -1. - g 1 u tamate). Both from the academic and industrial points of view, polyesters are by far the most important representatives of this class of polymers. 

Long amino acid polymers or polypeptides constitute the basic structural unit of proteins, and the structure of a protein provides insight into how it fulfills its functions. 

As described in Sect. 7.1, novel hybrid block copolymers comprising on one hand a classical synthetic polymer and on the other hand a metal-containing polymer, a synthetic or natural (proteine, enzyme, etc.) polypeptide have recently been synthesized. Other hybrid block copolymers containing inorganic blocks, dendrimers, etc. will certainly be prepared and thoroughly investigated in the next few years. 

Polymers and resins Water purification, including removal of phenol, chlorophenols, ketones, alcohols, aromatics, aniline, indene, polynuclear aromatics, nitro- and chlor-aromatics, PCB, pesticides, antibiotics, detergents, emulsifiers, wetting agents, kraftmill effluents, dyestuffs recovery and purification of steroids, amino acids and polypeptides separation of fatty adds from water and toluene separation of aromatics from ahphatics separation of hydroquinone from monomers recovery of proteins and enzymes removal of colours from symps ... 

The continuous availability of trillions of independent microreactors greatly multiplied the initial mixture of extraterrestrial organics and hydrothermal vent-produced chemicals into a rich variety of adsorbed and transformed materials, including lipids, amphiphiles, chiral metal complexes, amino add polymers, and nudeo-tide bases. Production and chiral amplification of polypeptides and other polymeric molecules would be induced by exposure of absorbed amino adds and organics to dehydration/rehydration cydes promoted by heat-flows beneath a sea-level hydro-thermal field or by sporadic subaerial exposure of near-shore vents and surfaces. In this environment the e.e. of chiral amino adds could have provided the ligands required for any metal centers capable of catalyzing enantiomeric dominance. The auto-amplification of a small e.e. of i-amino adds, whether extraterrestrially delivered or fluctuationally induced, thus becomes conceptually reasonable. 

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