Decreased activity of proteins adsorbed onto glass surfaces with porous glass as a reference

The biological activity of proteins bound to controlled-pore glass surfaces was studied as a model of denaturation of biologicals upon storage in glass containers. After adsorption onto the glass for 1 week, the activities of alkaline phosphatase, catalase, and horse-radish peroxidase recovered from the glass column were 88, 63, and 97%, respectively. However, the phosphatase activity recovered after adsorption for 3 months was 14% of the total activity loaded onto the column, and the activities recovered of peroxidase and catalase were 48 and 2%, respectively. Insulin had almost full activity after adsorption for 3 months, but calcitonin activity was absent. The scission of peptide bonds of proteins eluted after adsorption for 3 months was not observed, but dissociation to the subunits was found. The proteins were active in the state adsorbed onto glass surfaces.