title: Dehydrogenase-modified carbon-fiber microelectrodes for the measurement of neurotransmitter dynamics. 2. Covalent modification utilizing avidin-biotin technology.
abstract: Dehydrogenase enzymes are immobilized onto carbon-fiber microelectrode surfaces via avidin-biotin technology and a covalently linked hydrophilic tether. The avidin-biotin coupling strategy allows the selectivity of the electrochemical measurement to be easily changed without reoptimizing the immobilization conditions. Optimized derivatization conditions are demonstrated for dimer, tetramer, and hexamer dehydrogenases. Nonelectroactive substrates (ethanol, glucose-6-phosphate, and glutamate) are quantitated through the detection of enzyme-generated NADH by fast scan cyclic staircase voltammetry (100 V/s). The glutamate dehydrogenase-modified microelectrode possesses a 300-ms response time with a detection limit of 0.5 mM glutamate and a 1-60 mM linear concentration range.
authors.affiliation: Department of Chemistry, University of California, Riverside 92521.
authors.forename: P
authors.initials: P
authors.lastname: Pantano
authors.forename: W G
authors.initials: WG
authors.lastname: Kuhr
mesh_terms: D001360:Avidin / Q000737:chemistry; D015374:Biosensing Techniques; D001710:Biotin / Q000737:chemistry; D004800:Enzymes, Immobilized; D005969:Glutamate Dehydrogenase / Q000378:metabolism*; D005971:Glutamates / Q000032:analysis*; D008839:Microelectrodes; D018377:Neurotransmitter Agents / Q000032:analysis*; D011108:Polymers
chemical_list: D004800:Enzymes, Immobilized; D005971:Glutamates; D018377:Neurotransmitter Agents; D011108:Polymers; D001360:Avidin; D001710:Biotin; D005969:Glutamate Dehydrogenase