Polyvinylpyrrolidone binding

Thus one might expect flexible, water-soluble synthetic polymers with suitable side chains to show strong affinities for small molecules. In the course of 20 years we examined the binding ability of polyvinylpyrrolidone, polyvinylpyridine, polylysine, polyacrylamide, polyisopro-pylacrylamide, polyvinylimidazole, polyvinylmethyloxazolidinone,... 

Other investigators have also studied similar synthetic polymers.11-17 In our experience no water-soluble polymer binds small molecules with an avidity comparable to serum albumin. A comparison of the latter with two of the best-binding polymers18 is shown in Fig. 1. Neither polymer binds as strongly as serum albumin. Despite its large cationic charge and many apolar (—CH2—CH2—CH2—CH2—) side chains, polylysine shows very weak affinity for anions. Polyvinylpyrrolidone is more effective but not impressive. 

Fig. 1. Comparison of binding affinities of bovine serum albumin (BSA), polyvinylpyrrolidone (PVP), and polylysine (POLYLYS) for methyl orange anions (A), in acetate buffer, pH 5.6, 0.1 ionic strength, and 25°C.

Blots are prehybridized to block all nonspecific binding (which causes background). To do this, one first wets the nitrocellulose in 3 X SSC, then in 50% formamide, 3X SSC, 0.1% sodium dodecyl sulfate (SDS), 1 mM EDTA (pH 8.0), 10 mM Tris (pH 7.5), 10X Denhardt s solution [1X Denhardt s is 0.02% Ficoll, 0.02% bovine serum albumin (BSA), and 0.02% polyvinylpyrrolidone 360], 0.05% sodium pyrophosphate, and 100 /ig/ml denatured DNA. Denatured DNA is sheared herring or salmon sperm DNA that has been boiled for 10 min before addition to the prehybridization mix. Blots are sealed within plastic bags, placed between two glass plates to give uniform distribution of prehybridization solution over the blot, and incubated in a water bath at 37° for at least 1 hr. 

Some water-soluble polymers like polyvinylpyrrolidone 16 63-6S) and poly (methacrylic add) 17 (66) are known to bind many organic molecules in aqueous s3rstems. This peculiar behavior has been explained based on the hydrophobic nature... 

Harvath, L., Falk, W., and Leonard, E. J. (1980) Rapid quantitation of neutrophil chemotaxis use of a polyvinylpyrrolidone-free polycarbonate membrane in a multi well assembly. J Immunol Methods 37,39-45 9 Van Epps, D. E., and Chennoweth, D. E. (1984) Analysis of the binding of fluorescent C5a and C3a to human peripheral blood leukocytes. J. Immunol 132, 2862-2867. 

A tetraanionic porphyrin with four p-sulfonatophenyl substituents on the methine bridges (PTS) binds to cationic polyvinylpyrrolidone (PVP) with an equilibrium constant of 1.4 x 10 M . As with all other me o-tetraphenyl derivatives, there is no sign of porphyrin-porphyrin interaction in the UV/VIS spectrum. Light-scattering measurements of the polymer at optimum ratios of PVP to PTS showed, however, that only one porphyrin per four PVP was bound, although the binding constant was extremely high. ... 

Using proteins as an example, the purpose of blocking is to cover sites on the membrane that do not contain protein so you get nonspecific binding. Proteins adhere to nitrocellulose. If you block the other areas to prevent staining other compounds then you do not need to remove these other compounds. Some good blocking agents for proteins are nonfat dry milk, bovine serum albumin (BSA), and polyvinylpyrrolidone (PVP). 

Thus, the anionic NaCMC, using dynamic dialysis, has demonstrated the highest limiting binding capacity for the antibiotic chloramphenicol as compared with PEGs, polyvinylpyrrolidones and gelatin [106]. The preservatives parabens sodium influence the viscosity and the zeta potential of NaCMC gels... 

Lectin blots are blocked with substances free from lectin-binding glycoproteins (Tween, polyvinylpyrrolidon 360, purified BSA, periodate-oxidized BSA, hemoglobin). Milk powder and the cheaper BSA preparations contain glycoproteins. A control strip of the blot should be incubated with lectin and competing sugar and show no stain. Don t forget many lectins bind only in the presence of cofactors (e.g., Ca , Mg +, or Mn +). 

P. Molyneux and S. Vekavakayanondha, The interaction of aromatic compounds with polyvinylpyrrolidone in aqueous solution. Part 5. Binding isotherms for phenols and 0-substituted phenols, J. Chem. Soc. Faraday Trans. 2, 82 291 (1986). 

Cl NMR relaxation to study the binding of CDCl to polyvinylpyrrolidone. In Fig. 2.11 the observed relaxation rates divided by those of... 

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