Investigating the activity of cyclomaltodextrinase stabilized on the surface of superparamagnetic iron oxide nanoparticles with modified core-shell

The cyclomaltodextrinase (CDase) belongs to the enzymes of the glycohydrolase family that participates in the starch degradation process. The enzyme specifically decomposes cyclomaltodextrin (CD) into maltose and glucose. In the present study, CDase was stabilized on the surface of superparamagneticiron oxide nanoparticles (SPIONs). Firstly, the SPIONs were synthesized in the presence of ammonia in a sedimentary method. The surface of the nanoparticles was coated using tetraethoxysilane (TEOS) and 3-Aminopropyltriethoxysilane(APTES) containing hydroxyl and amine functional groups, respectively. Finally, the enzyme was coupled to the SPIONs using 5 μg and 2 μg EDC and NHS, respectively. The activity of both stabilized and the non-stabilized enzyme was measured and compared with each other by the DNS method. The structure of synthesized SPIONs was also studied by scanning electron microscope (SEM). According to the SEM results, the shape of the synthesized SPIONs was spherically and they were 35 nm in size. Our results also showed that the efficiency of conjugation enzyme on the SPIONs using Bradford method was 98%, demonstrating that the stability of the immobilized enzyme increased in comparison with the free enzyme. The results of such studies could improve CDase properties enabling it to be applicable in a wide range of temperature, and after a longterm storage.

Keywords:

Cyclomaltodextrinase , Enzyme stabilization , Superparamagnetic Iron Oxide Nanoparticles (SPIONs)