l-asparaginase immobilized p(HEMA-GMA) cryogels: A recent study for biochemical, thermodynamic and kinetic parameters

Abstract

Cryogels have recently been attracted intense attention as suitable carriers for enzyme immobilization. Herein, l-asparaginase was selected as the model enzyme due to its application such as pharmaceutical and food. Under optimum conditions, l-asparaginase was immobilized on poly (2-hydroxyethyl methacrylate-glycidyl methacrylate) cryogels with 68.8% of immobilization yield and 69.3% of activity recovery. The immobilized enzyme exhibited improved stability with respect to the soluble enzyme at extreme conditions, especially around acidic pH and high temperature. Also, the storage stability and reusability of the immobilized enzyme were found to be approximately 54% and 52% of the original activity after 28 days at room temperature and 10 cycles, respectively. The thermodynamic studies indicated that activation energy (Ea) of the free enzyme decreased from 13.08 to 10.97 kJ/mol, which means an increase in the thermostability of l-asparaginase. The Michaelis-Menten constants (Km) of 2.04 and 1.67 mM, and the maximum reaction rates (Vmax) of 170.0 and 115.0 μM min−1 were estimated for soluble and immobilized l-asparaginase, respectively. These findings demonstrated that the designed cryogels turn out to be a good carrier matrix for l-asparaginase immobilization with high catalytic efficiency and enhanced stability.

Keywords

• p(HEMA-GMA) cryogel
• Immobilization
• l-asparaginase
• Enzyme stability