Proteins stability immobilization

The following protocol for passive adsorption is based on methods reported for use with hydrophobic polymeric particles, such as polystyrene latex beads or copolymers of the same. Other polymer particle types also may be used in this process, provided they have the necessary hydrophobic character to promote adsorption. For particular proteins, conditions may need to be optimized to take into consideration maximal protein stability and activity after adsorption. Some proteins may undergo extensive denaturation after immobilization onto hydrophobic surfaces therefore, covalent methods of coupling onto more hydrophilic particle surfaces may be a better choice for maintaining native protein structure and long-term stability. 

Liu et al. have demonstrated that the direct electron transfer reactivity of the immobilized hemoglobin (Hb) can be effectively enhanced by the addition of MWNTs into the PUE film (118). Biosensors based on the direct electron transfer of the immobilized proteins show good analytical performance, including high sensitivity, acceptable fabrication reproducibility, and storage stability. 

Proteins are known to get denatured by exposure to heat, chemictJ denaturants, extreme pH, and organic solvents. Although immobilization imparts stability, even in the most favorable cases, this stability is not unlimited (36). In general, the denaturation/inactivation of immobilized proteins may be broadly divided into two kinds of processes (37) reversible and irreversible. 

These challenges will lead to a continuation of the efforts to find new ways to immobilize and to stabilize the immobilized proteins, both native proteins and those produced through rDNA technology. 

As shown, a reversible redox couple for immobilized protein was observed. Furthermore, the absorption bond of hemoglobin cobalt- oxide fdm (Curve b) is 407 nm similar to that of hemoglobin in pH buffer solution (Curve a), indicates no observable denaturation of hemoglobin happened on cobalt oxide film The immobilized hemoglobin shows excellent stability at wide pH range with high electron transfer rate constant, 1.4 0.1 s 1. 

In this chapter we will focus on the most recent developments in the use of nanostructured materials such as nanoclays, carbon nanotubes and magnetic nanoparticles for enzyme immobilization and stabilization, together with their potential applications in various fields, such as development of biosensors and biofuel cells, biocatalytic processes, enzyme purification/separation, intracellular protein transportation etc. 

One approach to develop more biologically compatible surfaces for immobilizing proteins is to incorporate a matrix, such as a hydrogel, as an interface between the protein and the solid surface (Burnham et al. 2006). The entrapment of enzymes in a hydrogel layer provides excellent long-term stability and the possibility to adjust the polymer matrix to the specific needs of a certain enzyme. Hydrogels are useful for linking proteins to solid surfaces because their hydrophilic nature and porous structure can help to keep these labile molecules in the native functional state. 

Protein stabilization after direct immobilization or capture When using unstable proteins, e.g., multimeric or autoproteolytic proteins or an unstable capture system... 

Chang L Q, Shepherd D, Sun J, et al. (2005). Mechanism of protein stabilization by sugars during freeze-drying and storage Native structure preservation, specific interaction, and/or immobilization in a glassy matrix J. Pharm. Sci. 94 1427-1444. 

---