Sugar additives, enzyme stabilization

Enzyme solutions can be stabilized using sugars, polyhydric alcohols, polymers, or salts [65]. These compounds affecting the enzyme stability are ligands (substate, product, inhibitor, coenzymes) or nonspecific additives. 

Brennan, J.D., Benjamin, D., DiBattista, E. and Gulcev, M.D. (2003) Using sugar and amino add additives to stabilize enzymes within sol-gel derived silica. Chemistry of Materials, 15, 737-745. 

A wide range of additives can also be introduced into the sol-gel matrices in order to modulate the hydrophobicity of the materials and to improve enzyme stability, activity and accessibility, leading to hybrid or even composite sol-gel matrices. Polymers [157,179,180] such as polyethyleneglycol, polyvinylpyrrolidone, polyvinylalcohol, polyglycidol, polyethyleneimine, polyacrylate have been simultaneously entrapped with enzymes in a siloxane matrix, as well as organic additives (sugar, amino add)... 

Stabilization with sugar additives. In general it is necessary to immobilize enzymes for two reasons. Firstly, because it helps to improve their stability and hence the lifetime of the device in which they are operating secondly because we do not want them to escape The enzyme needs to be held in the matrix and in the case of an elec-... 

The addition of polyhydroxyl compounds to enzyme solutions have been shown to increase the stabilities of enzymes, (13,16,19,20). This is thought to be due to the interaction of the polyhydroxyl compound, (e.g. sucrose, polyethylene glycols, sugar alcohols, etc), with water in the system. This effectively reduces the protein - water interactions as the polyhydroxy compounds become preferentially hydrated and thus die hydrophobic interactions of the protein structure are effectively strengthened. This leads to an increased resistance to thermal denaturadon of the protein structure, and in the case of enzymes, an increase in the stability of the enzyme, shown by retention of enzymic activity at temperatures at which unmodified aqueous enzyme solutions are deactivated. 

In a complementary structural study of stress-specific stabilization using FTIR spectroscopy, Prestrelski et al. [9] found that the recovery of activity after rehydration correlated directly with the ability of the additives to preserve the native structure of the enzymes in the dried state. Full activity recovery and maintenance of essentially aqueous structure in dried samples were only noted when a combination of PEG and sugar was employed. Based on these results, Prestrelski et al. [9] have proposed a model of the conformational events during lyophiliza-tion and rehydration, which is shown in Figure 8. Briefly, this model proposes that... 

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