Alkaline Phosphatase insolubilized by Covalent Linkage to Porous Glass

Abstract

ENZYMES have been covalently linked to organic polymers^1–7 or immobilized in starch⁸ and acrylamide gels⁹. These derivatives are susceptible to microbial attack, and, when used in chromatography columns, vary in flow rates and apparent pore size with changing pH and solvent conditions. Here I describe the covalent coupling of bacterial alkaline phosphatase (Worthington Biochemical Corp., Freehold, NJ) to an inorganic carrier, porous glass, thereby eliminating many problems inherent in the use of organic carriers. Inorganic carriers, for example, are not susceptible to microbial attack; by using a glass in which the pore diameter is smaller than that of a bacterial cell, the enzyme cannot be utilized as substrate unless the organism produces an extra cellular protease, and porous glass is unaffected by the changes in pH and solvent conditions generally associated with the use and study of biological molecules.