Macromolecular probes

Meyer, F.A., Koblentz, M. and Silberberg, A. (1977) Structural investigation of loose connective tissue by using a series of dextran fractions as non-interacting macromolecular probes. Biochem. J., 161, 285-291. 

Some macromolecular probes (e g., BSA-FITC) were found to be significantly adsorbed onto the cell membrane, especially after exposure to LEF. In order to differentiate between internalized and adsorbed fractions, the cells are subjected, in the case of proteins, to 0.01% trypsin in PBS for 5 min at 37°C. The trypsin-digested BSA-FITC represents the amount of BSA adsorbed onto the cells, whereas the amount of the probe measured in the cells after trypsinization is attributed to the internalized fraction. 

Berek, D. Evaluation of high-performance Uquid chromatography column retentivity using macromolecular probes I. J. Chromatogr. A, 2002, 950 (1 2), 75 0. 

Complex receptors typically have a multiplicity of reactive residues outside the ligand binding site. Nonspecific reaction of affinity labels with these groups can be a serious problem. Some of these residues are likely to be accessible only to small molecules. Hence, the amount of nonspecific labeling will be less when a macromolecular probe is used. 

Spin Labelling - In recent years there has been a great deal of emphasis on the preparation and study of various kinds of macromolecular probes. Probes may be defined as small molecules, some measurable property of which is altered as the result of non->fCovalent attachment to a blopolymer. Fluorescence, optical absorption, NMR, and electron-spin resonance have all formed the basis for the design of probing molecules. While all of these techniques have their... 

Abstract This chapter discusses the potential of fluorescence correlation spectroscopy (PCS) to study polymer systems. It introduces the technique and its variations, describes analysis methods, points out advantages and limitations, and summarizes PCS studies of molecular and macromolecular probes in polymer solutions, polymer gels, polymer nanoparticles, and polymeric micellar systems. In addition, a comparison with other experimental methods is presented and the potential of a combination with simulations discussed. 

Translational diffusion within polymer brushes can be also accessed by FCS studies. It depends on the local viscosity within the brush and on probe size, thus causing different results for small and macromolecular probes [156]. For charged polymers, pH and ionic strength plays an additional role. If the dyes and the brushes are oppositely charged a dynamic association of dye molecules with the polymer... 

Fluorescent probes are divided in two categories, i.e., intrinsic and extrinsic probes. Tryptophan is the most widely used intrinsic probe. The absorption spectrum, centered at 280 nm, displays two overlapping absorbance transitions. In contrast, the fluorescence emission spectrum is broad and is characterized by a large Stokes shift, which varies with the polarity of the environment. The fluorescence emission peak is at about 350 nm in water but the peak shifts to about 315 nm in nonpolar media, such as within the hydrophobic core of folded proteins. Vitamin A, located in milk fat globules, may be used as an intrinsic probe to follow, for example, the changes of triglyceride physical state as a function of temperature [20]. Extrinsic probes are used to characterize molecular events when intrinsic fluorophores are absent or are so numerous that the interpretation of the data becomes ambiguous. Extrinsic probes may also be used to obtain additional or complementary information from a specific macromolecular domain or from an oil water interface. 

Moreover, the molecular structural, synthetic, and property nuances of these polymers illustrate many of the attributes, problems, and peculiarities of other inorganic macromolecular systems. Thus, they provide a "case study" for an understanding of what may lie ahead for other systems now being probed at the exploratory level. In short, an understanding of polyphosphazene chemistry forms the basis for an appreciation of a wide variety of related, inorganic-based macromolecular systems and of the relationship between inorganic polymer chemistry and the related fields of organic polymers, ceramic science, and metals. 

Varadaraj R, Branham KD, McCormick CL, Bock J (1994) Analysis of hydrophobi-cally associating copolymers utilizing spectroscopic probes and labels. In Dubin P, Bock J, Davis R, Schulz DN, Thies C (eds) Macromolecular complexes in chemistry and biology. Springer-Verlag, Berlin, p 15... 

The application of heterobifunctional cross-linkers allows macromolecular PAL to probe protein-protein interactions, including subunit interactions and location, monitoring the conformational changes induced by signal transmission. 

These traps, (Fig. 6) and similar effects in the motion of holes and other charges through polymers, would eventually be correlated also with such structural probes as positron lifetimes in macromolecular solids. Extensive recent studies of positron lifetime are based on positronium decay. In this, the lifetime of o-positronium (bound positron-electron pair with total spin one) is reduced from about 140 nanoseconds to a few nanoseconds by "pick-off annihilation" in which some unpaired electron spins in the medium cause conversion quenching of orthopositronium to para-positronium. The speed of the t2 effect is supposed, among other things, to represent by pick-off annihilation the presence of defects in the crystalline lattice. In any case, what amounts to empty space between molecules can then be occupied by orthopositronium.(14,15,16) It is now found in linear polyethylene, by T. T. Wang and his co-workers of Bell Laboratories(17) that there is marked shift in positron lifetimes over the temperature range of 80°K to 300°K. For... 

Emnk M. R. (1991b) Fluorescence Quenching Reactions. Probing Biological Macromolecular Structures, in Dwey T. G. (Ed.), Biophysical and Biochemical Aspects of Fluorescence Spectroscopy, Plenum Press,... 

Newman, K.D., Kwon, G.S., Miller, G.G., Chlumecky, V., Samuel, J., Cyto-plasmatic delivery of a macromolecular fluorescent probe by poly(D,L-lactic-co-glycolic acid) microspheres. J Biomed Mater Res 50, 591-597 (2000). 

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