Acid-stable amperometric soybean peroxidase biosensor based on a self-gelatinizable grafting copolymer of polyvinyl alcohol and 4-vinylpyridine

A peroxidase was extracted from Chinese soybean seed coat, and its thermost ability and acid-stability were characterized. This peroxidase was immobili zed into a self-gelatinizable grafting copolymer of polyvinyl alcohol with 4-vinylpyridine(PVA-g-PVP) to construct an acid-stable hydrogen peroxide bi osensor. The effect of pH was studied for optimum analytical performances b y amperometric and spectro-photometric methods, also the K-m(app) and the s tability of the soybean peroxidase-based biosensor are discussed. At pH 3.0 , the soybean peroxidase maintained its bioactivity and the enzyme electrod e had a linear range from 0.01 to 6.2 mM with a detection limit of 1.0 x 10 (-7) M. In addition, the main characteristics of different hydrogen peroxid e sensors were compared.