Electrochemical quantification of β-glucosidase activity for inhibitor screening applications

The measurement of enzymatic activity of glucosidases is essential for its use in various clinical and industrial applications. Inhibitors of these enzymes are promising candidates as antidiabetic drug. This study presents the development of an electrochemical device for quantifying β-glucosidase activity using an electrochemical transduction method. Enzyme activity was evaluated in a citrate buffer solution with p-arbutin (hydroquinone-β-D-glucopyranoside) as the substrate, employed for the first time in this context. The enzymatic hydrolysis of the glycosidic bond produced hydroquinone, which was quantified via voltammetric measurements to determine the hydrolysis rate. To develop a device for the screening of inhibitory effects on glucosidase, this enzyme was immobilized into silica matrix and its activity was evaluated. Entrapped enzyme shows partial retention of its catalytic function that can be measured by means of the electrochemical transduction. The inhibitory effects of various sugars and acarbose (a commonly used antidiabetic drug) were investigated using the sensor with the immobilized enzyme. Inhibition rates detected ranged from 87 % to 13 % for the sugars and 17 % for acarbose.