Immobilization carrier property

Immobilized enzyme systems can be differentiated according to mode of immobilization, carrier properties, and rate-determining step. 

Of greatest interest are those compounds that attempt to model hemoglobin directly. Simple iron(II) porphyrins are readily autoxidized first to superoxo species, then to //-peroxo dimers and finally to /x-oxo dimers, as represented in equation (60). Bridge formation must be prevented if carrier properties are to be observed. This has been achieved by the use of low temperature and sterically hindered or immobilized iron(II) porphyrins. Irreversible oxidation is also hindered by the use of hydrophobic environments. In addition, model porphyrins should be five-coordinate to allow the ready binding of 02 this requires that one side should be protected with a hydrophobic structure. Attempts have also been made to investigate the cooperative effect by studying models in which different degrees of strain have been introduced. 

All the existing methods of immobilization involve formation of a high local BAS concentration and retention of its biological activity. In this respect, the use of disperse forms of CP as carriers of BAS used for different purposes is very promising [88]. In this case, the CP-protein interaction is an important factor in controlling the structure and properties of these systems. 

Poly (p-nitrophenyl acrylate)-coated wide-pore glass (WPG) was also used as an activated carrier for the immobilization of biospecific ligands and enzymes, A detailed description of properties of these sorbents and catalysts as well as some specific features of their functioning is given in Sect. 6. 

If the generation process is characterized by the primary quantum efficiency rj, the transport properties by the mobility /1, and the recombination by the free-carrier liefetime t, the steady-state photoelectric current can in the case of mobile electrons and immobile holes generally be described by Eq. (13) 14> ... 

Abstract. Adsorption of antioxidants (vitamins C and E) from aqueous and ethanol solutions on unmodified and partially hydrophobized nanosilica A-200 was studied using UV spectroscopy and quantum chemical methods with consideration for the solvent effects. Antioxidant power of silica nanocomposites with immobilized vitamins was evaluated by measuring the total polyphenolic index following the Folin-Ciocalteu method. It has been shown that immobilization of vitamins on silica surface leads to their stabilization. Being released from the carrier molecules of vitamins do not lose their antioxidant properties... 

Highly disperse silica is widely used in pharmaceutical formulations as a filler, adsorbent, thickener etc.5 Their high hydrophilicity and the absence of emulsifying ability restrict their application. In contrast to hydroxylated silica, partially or fully hydrophobized silica may exhibit improved properties as a drug carrier. The main goal of this work is to study hydrophobized silica nanocomposites with immobilized vitamins C and E. Investigations of adsorption-desorption processes which involve silica nanoparticles and the antioxidants are described. Factors affecting the antioxidant stability have also been carefully considered. 

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