Molecular heterogeneity

Molecular Heterogeneous Catalysis, Wiley-VCH Verlag GmbH, Weinheim. (a) Bligaard, T., Norskov, J.K., Dahl, S., Matthlesen, J., Christensen, C.M., and... 

Sieghart, W and Karobath, M (1980) Molecular heterogenity of benzodiazepine receptors. Nature... 

For molecularly heterogeneous polymers this equation must be used in place of (52). 

Protein macromolecules present in biological fluids are almost invariably heterogeneous in their characteristics. They may be products of more than one gene in the population (allotypes in the case of proteins isoenzymes in the case of enzymes), or a single individual (isotypes of proteins, allelozymes of enzymes), or be subject to post-translational modification. The result of this inherent molecular heterogeneity is that different forms of the same protein may behave differently with respect to... 

B17. Beutler, E., Kuhl, W., Vives-Corrons, J.-L., and Prchal, J. T., Molecular heterogeneity of glu-cose-6-phosphate dehydrogenase A—. Blood 74,2550-2555 (1989). 

K11. Kanno, H Fujii, H., and Miwa, S Molecular heterogeneity of pyruvate kinase deficiency identified by single strand conformational polymorphism (SSCP) analysis. Blood 84 (Suppl. 1), 13a... 

Rajotte, D., Arap, W., Hagedom, M., Koivrmen, E., Pasqualini, R., and Ruoslahti, E. (1998). Molecular heterogeneity of the vascular endothelium revealed by in vivo phage display. J. Clin. Invest. 102, 430-437. 

State-of-the-art polymeric materials possess property distributions in more than one parameter of molecular heterogeneity. Copolymers, for example, are distributed in molar mass and chemical composition, while telechelics and macromonomers are distributed frequently in molar mass and functionality. It is obvious that n independent properties require n-dimensional analytical methods for accurate (independent) characterization of the different structural parameters. 

To conclude, the LCCC method was superior to the gradient LC method because the separation took place mainly according to the end groups. The selectivity of LCCC is lower than the gradient technique however, the 2D plots give a clear picture of the molecular heterogeneity of the samples. The method appearsto be suitable for in-depth studies of the hydrolytic degradation of polycarbonates. 

Screening the molecular heterogeneity of receptor expression in endothelial cell surfaces is required for the development of vascular-targeted therapies. First, as opposed to targeting purified proteins as discussed above, membrane-bound receptors are more likely to preserve their functional conformation, which can be lost upon purification and immobilization outside the context of intact cells. Moreover, many cell surface receptors require the cell membrane microenvironment to function so that protein-protein interaction may occur. Finally, combinatorial approaches may allow the selection of cell membrane ligands in a functional assay and without any bias about the cellular surface receptor. Therefore, even as yet unidentified receptors may be targeted. 

The nervous system contains an unusually diverse set of intermediate filaments (Table 8-2) with distinctive cellular distributions and developmental expression [21, 22]. Despite their molecular heterogeneity, all intermediate filaments appear as solid, rope-like fibers 8-12 nm in diameter. Neuronal intermediate filaments (NFs) can be hundreds of micrometers long and have characteristic sidearm projections, while filaments in glia or other nonneuronal cells are shorter and lack sidearms (Fig. 8-2). The existence of NFs was established long before much was known about their biochemistry or properties. As stable cytoskeletal structures, NFs were noted in early electron micrographs, and many traditional histological procedures that visualize neurons are based on a specific interaction of metal stains with NFs. 

Robertson, D. H., Hurst, J. L., Bolgar, M. S., Gaskell, S. J. and Beynon, R. J. (1997) Molecular heterogeneity of urinary proteins in wild house mouse populations. Rapid Commun. Mass Spectrom. 11, 786-90. 

It was soon realized (J10, R5) that Hp did not consist of a single protein, but of a group of proteins with very similar properties. Conclusive evidence of the molecular heterogeneity of Hp was produced by Smithies (S5), who used electrophoresis with a defined starch gel in which the mobility of protein molecules varies with their charge and size (Fig. 1). Smithies and Walkers discovery (S9) of different types of... 

So far, no attempts have been made to formulate a precise biochemical or biological definition of Hp s. This lack of an exact definition may be explained, at least to some extent, by the molecular heterogeneity of Hp s and by the insufficiency of our knowledge of the homeostasis and of the biological significance of Hp s. 

Solubility curves for different types of Hp have been presented (H5, H7). The higher solubility of type 1-1 than that of the others is in conformity with its lower molecular weight. The irregularity of the solubility curves for Hp of 2-2 and 2-1 type reflects the molecular heterogeneity of these two proteins. It is known from fractionation experiments with ammonium sulfate as well as with ethanol that the slower Hp bands are enriched in those Hp fractions that are precipitated first. So far, we have not been able to separate any of the Hp bands completely from the others, except the 1-1 band in ascitic fluid of type 2-1. 

The Hb solutions generally used are obtained by simple osmotic hemolysis of normal red cells followed by elimination of the ghosts. The molecular heterogeneity of such solutions of adult Hb is revealed by the starch-gel electrophoresis. The Hb line is therefore not quite distinct, which is a minor drawback when the solutions are used for Hp typing. To stabilize the Hb solutions, it is advisable to bubble CO through them before they are ampouled and stored in the frozen state. 

Bioassays can be used to assess the effect of molecular heterogeneity due to glycosylation, whereas ELISA cannot. The sensitivity of the bioassay and ELISA are often comparable. Both methods can be used as stability-indicating test methods. 

In order to fulfill the state of the art criteria of modern molecular heterogeneous catalysis, a conceptually new approach based on metathesis polymerization, that allows the synthesis of such supports by convergent synthetic route, starting from... 

Van Santen, R. A. Neurok, M. Molecular Heterogeneous Catalysis A Conceptual and Computational Approach -, Wiley-VCH Weinheim, 2006. 

Beynon, R. G., Veggerby, C., Payne, C. E., etal. (2002). Polymorphism in major urinary proteins molecular heterogeneity in a wild mouse population, journal of Chemical Ecology 28 1429-1446. 

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