Biological affinity

The detennination of biological affinity by mixing two species and measuring tlieir rates of association and dissociation presupposes tliat tire contribution of transport to tire association dynamics is precisely known. Well-defined hydrodynamic conditions are tlierefore a prerequisite for tire experimental detennination of affinities via rates. 

A classical Hansch approach and an artificial neural networks approach were applied to a training set of 32 substituted phenylpiperazines characterized by their affinity for the 5-HTiA-R and the generic arAR [91]. The study was aimed at evaluating the structural requirements for the 5-HTiA/ai selectivity. Each chemical structure was described by six physicochemical parameters and three indicator variables. As electronic descriptors, the field and resonance constants of Swain and Lupton were used. Furthermore, the vdW volumes were employed as steric parameters. The hydrophobic effects exerted by the ortho- and meta-substituents were measured by using the Hansch 7t-ortho and n-meta constants [91]. The resulting models provided a significant correlation of electronic, steric and hydro-phobic parameters with the biological affinities. Moreover, it was inferred that the... 

Kim G, Ree M, Kim H, Kim IJ, Kim JR, I-ee JI (2008) Biological affinity and biodegradability of poly(propylene carbonate) prepared from copolymerization of carbon dioxide with propylene oxide. Macromol Res 16 473-480... 

Complementary structures of biological materials, especially those of proteins, often result in specific recognitions and various types of biological affinity. These include many pairs of substances, such as enzyme-inhibitor, enzyme-substrate (analog), enzyme-coenzyme, hormone-receptor, and antigen-antibody, as summarized in Table 11.2. Thus, bioaffinity represents a useful approach to separating specific biological materials. 

Successful protein purification results from the exploitation of one or more of the many characteristics responsible for the wide diversity within the protein population, such as charge, size, hydro-phobicity, or biological affinity. Fortunately, in some properties immunoglobulins are distinctive and as a consequence an acceptable degree of purity can often be achieved using relatively straightforward procedures. 

The use of colloidal gold particles is now well established in the field of biological affinity labeling. Although the application of colloidal gold probes in microscopy has developed rapidly during the... 

The currently most relevant separation and purification techniques for processing biomolecules from animal cell cultures are discussed in the sections that follow. They are classified according to the protein characteristic on which the separation is based, such as solubility, molar mass, electrical charge, adsorption properties, and biological affinity for ligands. 

Immunoaffinity chromatography covers the real aspect of biological affinity purification. In the context of this review two distinct parts are considered (i) the immobilization of the antigen and (ii) the immobilization of specific antibodies both intended for the adsorption of the antibody to purify. 

Arouri K., Greenwood P. E., and Walter M. R. (2000b) Biological affinities of Neoproterozoic acritarchs from Australia microscopic and chemical characterisation. Org. 

Biological Affinity properties of antibodies (kinetic association and dissociation constants, binding constant) 123... 

Towards this end, studies were carried out which included the radio-labelling of the somatostatin receptor ligand DOTA-Tyr -TATE (1,4,7,10-tetraazacyclotetradecane-N,N, N",N" -tetraacetic acid tyrosineS-octreotate, or DOTATATE) with both Lu and I, and the quality control of the resulting complexes. In vitro studies of the biological affinity of the Lu-DOTATATE and I-DOTATATE for the somatostatin membrane receptor were carried out with the help of competition and saturation binding assays. In vivo studies of the biodistribution of Lu-DOTATATE and I-DOTATA TL in animals, either alone or in competition, were also carried out. The radiotherapeutic effect of "Lu-DOTATATE was evaluated by cytometry measurements. Estimation of absorbed doses of Lu-DOTATATE was carried out by mathematical modelling. 

A significant fraction of biomolecules display natural biological affinity for certain other species, e.g. immuno-ligands, enzyme substrates, hormones. These properties can be exploited in an affinity separation process to recover and purify biomolecules in a more effective way (i.e. with higher yield and higher resolution) than can be achieved with more conventional means of purification (e.g. size exclusion chromatography). 

The biofilm formation is a usual phenomenon closely related to the type of material because of its surface characteristics, such as roughness, surface energy, biological affinity , etc. (Flemming, 1991). Water flow may influence on biofilm growth with its chemical and hydraulic characteristics. 

In the reactions leading to the desired product (column A) many factors must be considered. They are of such importance that we devote several separate chapters to this Ch. 12 on nuclear reactions, Ch. 13 on particle accelerators and Ch. 15 on production of radionuclides. The incorporation of the radionuclide in a chemical compound (labelling, 15.5.3) provides it with unique properties, such as specific biological affinity ( 9.5.1). When such labelled compoimds are taken up by organisms (A4b - Bl) they move to specific sites in the organs, signalling normal or abnormal behavior. When used in medicine (primarily Cl and C3) these compounds are referred to as radiopharmaceuticals (A4b). 

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