Influence of salts on the covalent immobilization of proteins to modified copolymers of 2-hydroxyethyl methacrylate with ethylene dimethacrylate.

In the study of the covalent immobilization of aminoacylase, thermitase, pepsin, trypsin, chymotrypsin, elastase, subtilisin, penicillinamidohydrolase, carboxypeptidase A, cystathionine-beta-synthase, and anticathepsin D-IgG to copolymers of 2-hydroxyethyl methacrylate and ethylene dimethacrylate (Separon HEMA) containing epoxy groups a marked influence of added salts on the immobilization efficiency was observed. Yields in covalently bound active enzymes were dependent on the concentrations and type of ions added, which can be arranged according to the Hofmeister series. At a distinct concentration, the salting-out ions cause a protein-matrix hydrophobic interaction which is a prerequisite for the covalent bond formation.