[Immobilization of alpha-amylase on porous glass and silochrome]

Immobilized forms of alpha-amylase from Aspergillus oryzae were prepared on the porous glass and silochrome by the glutaraldehyde method. An addition of calcium ions at a concentration of 0.05 M to the reaction mixture during immobilization stabilized the enzyme activity. pH optimum of the insoluble form of alpha-amylase was 5.8 and that of the soluble form was 4.7. Storage of the insoluble enzyme as water suspension in 0.015 M CaCl2 at 4 degrees C for six months and twenty times repeated specific reaction did not affect significantly the activity of insoluble alpha-amylase.