Porous polymethacrylic acid-co-triethylene glycol dimethacrylate (MAA-co-3G) and polyacrylic acid-co-triethylene glycol dimethacrylate (AA-co-3G) were prepared by four different polymerization techniques, namely, suspension, dispersion, seed, and microemulsion polymerization using an inert diluent (n-hexane and polystyrene). The morphology and porosity of the obtained polymers were examined by means of a scanning electron microscope. The surface areas of the obtained polymers were determined colorimetrically. The copolymers were modified by hydroximation and chlorination using hydroxyl amine and thionyl chloride, respectively. The effect of polymerization type, surface area, modification, and pH on the protease enzyme immobilization over poly(MAA-co-3G) and poly(AA-co-3G) was examined. The enzyme activity was measured by means of a spectrophotometer. The reactivity ratios of the two monomers MAA and 3G were determined by means of the elemental analysis method. (C) 2000 John Wiley & Sons, Inc.