Characteristics of immobilized invertase.

Five kinds of immobilized invertases (IMI)-covalently of porous glass and ion-exchange resins and ionically on ion-exchange resins-have been prepared and their kinetic characteristics for sucrose hydrolysis, such as K , K, pH profile, and thermal stability were studied. Comparing the values of K and activation energy and the entropy of IMI with those of native invertase, it was concluded that the immobilization influences not binding but kinetic specificity. The effects of the immobilization method on thermal stability were also discussed.

Kinetic study on thermal stability of immobilized invertase.

The kinetic study of the thermal stability of three kinds of invertases: native, immobilized on porous glass covalently, and on ion-exchange resin ionically, has been carried out, measuring their enzymatic activity for sucrose hydrolysis. Thermal deactivations of all invertases obeyed first-order kinetics, being independent of substrate concentration, with k and ΔE , ΔS * as shown in Tables I and II, respectively. Based on these parameter values, the effects of immobilization and pH at deactivation on the stability have been considered, and it was suggested that the ionic bond gives a more loosely deformed enzyme than the covalent bond.