دراسة مقارنة للصفات الحركية للاسباراجينيز (L-asparaginase)‎ الحر و المقيد من العزلة المحلية Pseudomonase aeruginosa

Abstract EN

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°.