Cereal Chem 56:147 - 151. | VIEW
Preparation and Use of an Enzyme Electrode for Specific Analysis of L-Lysine in Cereal Grains.
D. Skogberg and T. Richardson. Copyright 1979 by the American Association of Cereal Chemists, Inc.
An enxyme electrode selective for L-lysine consisting of L-lysine decarboxylase immobilized at the surface of a CO2 electrode is described. An electrode responded linearly over a range of 10(-4) M to 10(-2) M L- lysine. Selectivity was good with no observed response to other common amino acids or to L-ornithine. The optimum pH (6.0), enzyme concentration (50 mg/ml), and buffer concentration (0.1M PO4) required for maximum electrode response were determined. Response time and recovery time of the electrode were diffusion-limited and total time for analysis varied from 15 to 25 min depending on L-lysine concentration. Results of analysis grain and feed samples using the L-lysine electrode compare favorably with lysine values obtained from automated amino acid analysis using ion exchange. The technique should prove useful as an inexpensive method of analyzing grain and feed samples for L-lysine.