title: Amperometric determination of lysine using a lysine oxidase biosensor based on rigid-conducting composites.
abstract: In this study, amperometric biosensors based on rigid conducting composites are developed for the determination of lysine. These lysine biosensors consist of chemically immobilized lysine oxidase membranes attached to either graphite-methacrylate or peroxidase-modified graphite-methacrylate electrodes. The enzymatic degradation of lysine releases hydrogen peroxide, which is the basis of the amperometric detection. The direct oxidation of hydrogen peroxide is monitored at +1000 mV with a graphite-methacrylate electrode, while with the peroxidase-modified electrode reductive detection is performed. In addition, for the peroxidase-modified biocomposite electrode, both direct electron transfer and hydroquinone-mediated detection are studied. For the lysine biosensor based on the hydroquinone-mediated peroxidase biocomposite, the linear range is up to 1.6 x 10(-4) M, the sensitivity 11300 microA/M, the repeatability 1.8%, the detection limit 8.2 x 10(-7) M and the response time t95% is 42 s. The proposed biosensors are used to determine lysine in pharmaceutical samples. Results are consistent with those obtained with the standard method.
authors: Department of Chemistry, Autonomous University of Barcelona, Bellaterra, Spain.
authors: J
authors: J
authors: Saurina
authors: S
authors: S
authors: Hernández-Cassou
authors: S
authors: S
authors: Alegret
authors: E
authors: E
authors: Fàbregas
mesh_terms: D015374:Biosensing Techniques; D004563:Electrochemistry; D004795:Enzyme Stability; D006863:Hydrogen-Ion Concentration; D008239:Lysine / Q000032:analysis*; D008249:Protein-Lysine 6-Oxidase / Q000378:metabolism*; D013696:Temperature
chemical_list: D008249:Protein-Lysine 6-Oxidase; D008239:Lysine