The purified asparaginase from local isolate of P. aeruginosa.was immobilized
by gel entrapment using polyacrylamide,agar,sodium alginate,ionic binding on
ionexchanger using DEAE-cellulose and immobilized in gelatin by cross-linking
with glutaraldehyde.
The later method was the most efficient method for immobilization since the
immobilized enzyme retained about 53.5% of original activity of free enzyme. The
optimal pH for immobilized enzyme activity was 7.5 and the enzyme was most
stable at pH 6-8.5, while the values of optimal pH for activity and Stability of free
enzyme were 8.5 and (7.5-8) respectively. The immobilized enzyme retained its
original activity when incubated at 25-45C° for 30 min., while the free enzyme
retained its original activity after 30 min. at 25-37C°. The obtained values of
Michaelis constant (Km) and Vmax for immobilized enzyme were 0.46×10-4 M and
12.2 μM/min.,respectively ,and the Km and Vmax for free enzyme were 0.25×10-4
M and 16.7 μM/min,respectively. The immobilized enzyme was highly specific
towards L-asparagine and L-glutamine. The free and immobilized enzyme retained
about 90.2% and 51% of its original activity after 3 weeks of storage at 4 C°.