L-GLUTAMATE ENZYME ELECTRODE INVOLVING AMPLIFICATION BY SUBSTRATE RECYCLING

An enzyme electrode with an amplified response for l-glutamate is constructed by co-immobilizing l-glutamate oxidase and glutamate-pyruvate transaminase on a platinum disk electrode. With l-alanine (1 mM) in the solution, the sensitivity of the electrode to l-glutamate is greatly increased by the substrate recycling reaction between the two enzymes; the detection limit is 0.2 nM in the presence of l-alanine compared with 0.2 μM in its absence. The amplification factor for 1 μM l-glutamate is ca. 53. © 1990.