IMMOBILIZATION OF PEPSIN ONTO WIDE- POROUS AND NONPOROUS SUPPORTS 61-AMINOALKYLDERIVATIZED INORGANIC

Heterogeneous catalysts were prepared by covalent binding of pepsin to wide-porous and nonporous w-aminoalkylderivatied inorganic supports by means of water-soluble carbodiimide. The amount of attached enzyme and the proteolytic activity of catalysts were determined. Nonporous catalyst, based on finely dispersed pyrogeneous silicon dioxide (Cabosil), exhibited the maximum pepsin content (22 nmol/g) and the highest proteolytic activity (5.6 units/g). Wide-porous glass-based catalyst showed the maximum retained pepsin activity (92%). The immobilized pepsin content as well as proteolytic activity of catalysts was found to increase on increasing the chain length of the alkyl spacer from C, to C,, whereas thermal stability of catalysts (37°C) was independent of the alkyl spacer length. All the catalysts tested were stable on storage at 8"C, pH4.5 for 1 month.