[Properties of amylase immobilized on aerosil derivatives]

The properties of three preparations of alpha-amylase immobilized on aminoaerosil by 2,4-toluylenediisocyanate and N,N'-dicyclohexylcarbodiimide as well as on carboxyaerosil by N,N'-dicyclohexylcarbodiimide were compared with the properties of soluble enzyme. Under immobilization the pH-effect and pH-stability zones of amylase are 0.5--1.0 pH units shifted towards the alkaline region. The preparations in which the enzyme is bound with the matrix through the amine groups on carboxyaerosil by N,N'-dicyclohexylcarbodiimide and on aminoaerosil by 2,4 toluylenediisocyanate are the most stable at 50 degrees C and to the EDTA effect. The preparation obtained by means of 2,4-toluylenediisocyanate contains a greater amount of the bound protein, is more active and stable.