A lysine dehydrogenase-based electrode for biosensing of L-lysine.
An amperometric biosensor for L-lysine based on the recently isolated enzyme lysine dehydrogenase is described. Immobilization of the enzyme onto a platinum electrode is achieved via entrapment within a gelatin support on a cellulose membrane. Anodic detection (at 0.4 V vs. Ag/AgCl) is facilitated by the presence of a redox-mediating ferricyanide ion. The effect of experimental variables such as pH, enzyme loading, applied potential, cofactor and mediator concentrations were evaluated in order to optimize the analytical performance. A detection limit of 7 x 10(-8) M, and linearity up to 7 x 10(-4) M are reported. The fast response permits adaptation for flow injection operation with good precision (RSD = 1.9%) and high sample throughout (40 samples per hour). The high specificity offered by this new enzyme is indicated by the lack of interference by other L-amino acids, alcohols or carbohydrates.
Dempsey
E
E
Department of Chemistry, New Mexico State University, Las Cruces 88003.
Wang
J
J
Wollenberger
U
U
Ozsoz
M
M
Smyth
M R
MR
D000594:Amino Acid Oxidoreductases / Q000737:chemistry*; D015374:Biosensing Techniques; D008239:Lysine / Q000032:analysis*
D000594:Amino Acid Oxidoreductases; C034168:lysine epsilon-dehydrogenase; D008239:Lysine