Improved Stabilization of Chemically Aminated Enzymes Via Multipoint Covalent Attachment on Glyoxyl Supports

Chemical modification and immobilization of proteins have been usually utilized as parallel techniques to improve enzyme stability. In this chapter, we show that chemical modification of the protein surface to greatly increase its reactivity with the groups of a support activated with glyoxyl residues may be a very good alternative for greatly increasing the protein stability via multipoint covalent attachment. For this purpose, some of the carboxylic acids of the proteins are transformed into amino groups by reaction with ethylendiamine via the carbodiimide coupling method. The new amino groups have a lower pK than Lys residues, enabling immobilization under milder conditions and a higher degree of stabilization. These results show that the coupling of different stabilization techniques may yield a synergistic effect, higher than any individual strategy.