| Popis: |
The use of brushite (CaHPO 4 ·2H 2 O) for enzyme immobilization is described and exemplified with β-galactosidase. Immobilization was carried out at 5°C in a 0.01 M Tris buffer, pH 7.6, containing 0.01 M phosphate. The immobilized enzyme showed high activity over a long period of time (after 90 days the activity was still 44% of the initial value). The leakage of enzyme from these matrices is very low, amounting to no more than 4% upon washing a column fully saturated with enzyme with 300 column volumes of buffer. A method is described in which the enzyme leakage is virtually negligible. One advantage of brushite as a matrix for enzyme immobilization is that the immobilization can be done in almost any buffer, even at high salt concentration, provided that high concentrations of phosphate are avoided. The immobilized enzymes can be desorbed easily by increasing the phosphate concentration. Since the enzyme is adsorbed at the top of the column, no preconcentration of the enzyme solution is required prior to immobilization. |
