Poly denatured polymer

Guner A. and Kara M. Cloud points and temperatures of aqueous poly(N-vinyl-2-pyrrolidone) solutions in the presence of denaturing agents. Polymer 39, 8 9, 1569-1572,1998. 

It should be pointed out that the addition of substances, which could improve the biocompatibility of sol-gel processing and the functional characteristics of the silica matrix, is practiced rather widely. Polyethylene glycol) is one of such additives [110— 113]. Enzyme stabilization was favored by formation of polyelectrolyte complexes with polymers. For example, an increase in the lactate oxidase and glycolate oxidase activity and lifetime took place when they were combined with poly(N-vinylimida-zole) and poly(ethyleneimine), respectively, prior to their immobilization [87,114]. To improve the functional efficiency of entrapped horseradish peroxidase, a graft copolymer of polyvinylimidazole and polyvinylpyridine was added [115,116]. As shown in Refs. [117,118], the denaturation of calcium-binding proteins, cod III parvalbumin and oncomodulin, in the course of sol-gel processing could be decreased by complexation with calcium cations. 

Numerous technologically important polymers, for example, many crystalline polyolefins are soluble only at the elevated temperature. Consequently, the high-temperature SEC instruments were designed, in which also dissolution and filtration of samples is performed at elevated temperature. Some SEC eluents such as hexafluoro isopropanol are very expensive, other ones are very aggressive—the extremes represent concentrated sulfuric acid [150] or hexamethyl phosphorotriamide [151] used as the mobile phase for some polyamides or cresols for polyesters [152]. Many biopolymers solicit the appropriate environment (eluent) and/or temperature of experiment below the ambient value to prevent their denaturation. Some polymers rapidly degrade in solution, for example, poly(hydroxy butyrate). These are to be separated as rapidly as possible and the data obtained should be corrected. 

Polypeptides and poly(a-amino acid)s have a quite unique position amongst synthetic polymers. The reason for this is that most common synthetic polymers have very little long range order in solution and their properties are the products of statistical random coil conformations. Polypeptides, in contrast, can adopt well defined, ordered structures typical of those existing in proteins, such as a-helix and P-struc-tures. Moreover, the ordered structures can undergo conformational changes to the random coil state as cooperative transitions, analogous to the denaturation of proteins. 

One candidate polymer system is the poly(ortho esters), which are pH-sensitive and undergo enhanced hydrolysis rates with decreasing external pH values (6). Furthermore, this system has demonstrated surface erosion characteristics and can be prepared in both linear and crosslinked forms (7., 8). The crosslinked form is particularly interesting because sensitive macromolecules can be incorporated into the polymer under very mild conditions and without denaturation. These mild conditions are important because both insulin and glucose oxidase are proteins. 

The high hydrophobicity of silicones can complicate their use in some applications. For example, proteins can undergo denaturation in contact with silicones [1]. In such cases, the siloxane can be modified to include a hydrophilic domain. This is typically accomplished by functionalizing the silicone with a hydrophilic polymer such as poly(ethylene oxide)(PEO). Silicone surfactants of this type have found widespread use as stabilizers for polyurethane foams, and have been investigated as a structurant to prepare siloxane elastomers for biomaterials... 

Immunization with homopolynucleotide-MBSA complexes gives rise to antibodies that are specific for an oligonucleotide segment of the polymer. They probably recognize a number of bases in sequence, perhaps in a stacked array. Poly(I), poly(C), and poly(A) each induce specific antibodies that show little cross-reaction with the other homopolynucleotides, and slight cross-reaction with denatured DNA. ... 

Many redox enzymes can be denatured if the pH of the solution is taken too far from neutral or if nonaqueous solvents are used. It is therefore desirable, although not always essential, to use neutral aqueous solutions in the electropolymerization process, thus restricting the choice of monomers that can be used. One way to overcome this problem is to incorporate, or immobilize, the enzyme after deposition of the polymer film. This allows a much wider choice of deposition conditions. In addition to adsorbing the enzyme onto preformed poly(pyrrole) films, " GOx has also been covalently immobilized onto a wide range of preformed 3- and N-derivatized pyrrole carboxylates or onto N-amino-substituted pyrroles. This technique may increase current densities at a given glucose concentration by as much as twentyfold when compared to the best results obtained elsewhere. The authors make no claims for direct electron transfer between enzyme... 

In addition to poly(pyrrole) and poly(N-methylpyrrole), other conducting polymers have been used for enzyme immobilization, including poly(thio-phene), poly(indole), and poly(aniline). " Poly(thiophenes) and poly (indole) films have the possible disadvantage that the enzyme/polymer film must be grown from aprotic solvents, conditions that may denature the enzymes. The... 

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