Abstract: A protein which can be an enzyme is immobilized by: (a) admixing the protein and an isocyanate-capped liquid polyurethane prepolymer in the absence of water to form a resulting mixture (an intermediate product); and (b) forming the intermediate product by reacting it with water to form a polyurethane foam comprising the immobilized enzyme. When certain proteins in sufficient amount are mixed with the prepolymer in the absence of water the resultant protein prepolymer mixture will solidify to produce a solid non-foamed product containing a protein immobilized therein. Initially mixing the protein and prepolymer in the absence of water results in immobilization of a substantially greater amount of protein than when water is present.

Abstract: An aqueous dispersion of a biologically-active protein bound to polyurethane is formed by (a) admixing the protein and an isocyanate-capped liquid polyurethane prepolymer to form a solution; and (b) dispersing the solution in water.