Analytical Uses of Immobilized Enzymes

Immobilized Biocatalysts

“…Because such compounds and ions are often involved in enzymatic reactions as reactants or products, these electrodes can be employed in conjunction with a suitable enzyme to monitor substrate concentration. Important reviews on enzymes and microbial sensors are given in [232][233][234][235][236][237]. A typical setup for this procedure is shown in Figure 21.…”

Sensors in Biomolecular Interaction Analysis and Pharmaceutical Drug Screening

“…Compounds can be immobilized directly at a transducer surface or in an immobilizing matrix [33]. Only if an extended threedimensional matrix is used for immobilization can the density of biochemical compounds (mostly proteins) at a device surface exceed monolayer coverage [34].…”

“…The physicochemical properties of a``prototype'' protein monolayer are given in Figure 7.4. Immobilization techniques are available from af®nity chromatography, biocompatibility studies and biosensor research [35,33]. Binding processes at a surface involve diffusional transport of the reactants to the surface and the reaction kinetics itself.…”

Enzyme Electrode with Enhanced Specificity Using Outer Polymeric Membrane Doped with Substrate Selective Ditopic Carrier

“…In many instances, the immobilized enzyme utilized to prepare such sensors is highly speci®c for a given substrate and the ultimate analytical selectivity of the ®nal sensor is governed primarily by the selectivity of the base transduction electrode (amperometric or potentiometric) onto which the enzyme layer is af®xed. However, there are instances where the enzyme employed is not highly speci®c, andaor is contaminated with other enzymes that catalyze similar reactions, and this leads to lack of sensor selectivity due to the speci®c nature of the biocatalytic layer [7], not the underlying electrochemical transducer. Moreover, other biocatalytic electrodes, such as the bacterial and tissue electrodes ®rst described by Rechnitz and co-workers in the 1970s and early 1980s [8±10] inherently have, in some cases, the potential to be less selective owing to the presence of many different enzymatic activities within the immobilized organism or tissue.…”

“…This enzyme is known to have broad substrate speci®city, catalyzing the conversion of most amino acids in the presence of oxygen into corresponding 2-oxo acids [4,7] in accordance with the following reaction:…”