Electrochemical study of catalytic activity of Erwinia carotovora L-asparaginase immobilized on bacterial cellulose films

In this work, we developed an electrochemical method for the determination of the catalytic activity of L-ASNase from Erwinia carotovora noncovalently immobilized by means of physical adsorption on bacterial cellulose (BC) films (BC/L-ASNase). Immobilization of enzymes on a support can refine stability and catalytic activity. Determination of enzyme on BC and catalytic activity evaluation of its immobilized form is based on the electrochemical oxidation of amino acids from L-ASNase active center and polypeptide backbones. The electrochemical behavior of L-ASNase on screen-printed electrodes modified with single-wall carbon nanotubes (SPE/CNTs) was studded. In the presence of the substrate L-asparagine, the oxidation current of the enzyme decreased in a concentration-dependent manner. The sigmoidal dependence of maximum peal current on substrate concentration was registered with parameters K0.5 = 800 µM and Hill positive coefficient as n = 3. The sensitivity, LOD and LOQ for L-asparagine were calculated as 0.89 μA/mM, 0.10 mM, and 0.28 mM.