Aminopropyl silica gel was prepared from porous silica gel by reaction with γ-aminopropyltrimethoxysilane in toluene and was used for immobilizing chymotrypsin (EC 3.4.4.5) and human serum albumin. Immobilized chymotrypsin was used for the resolution of N-acetyl-dl-phenylalanine and immobilized human serum albumin was used for the purification of goat anti-human serum albumin. Epoxy silica gel, prepared by reaction of porous silica gel with γ-glycidoxypropyltriethoxysilane, was coupled with m-aminobenzamidine and the resulting matrix was used for trypsin purification. © 1979.