Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P50583 (asymmetrical)
 12,197 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The theoretical analysis of the distribution on both sides of a flat porous membrane of the product generated by an enzyme covalently bound only on to one side of the membrane separating two compartments of widely different volumes is presented. Contrary to what occurs with heterogeneous symmetric systems, the diffusional limitations at the enzyme level play a prominent role, not only on the apparent enzyme activity, but also on product flux-splitting. The mathematical model developed shows that it is possible to concentrate the reaction product in the compartment opposite to that where the reaction occurs. The influence of the parameters and of the physical characteristics of an asymmetrical system on product distribution is analysed. This theoretical analysis is in excellent agreement with experimental data obtained with glucose oxidase immobilized on a porous collagen membrane.
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PMID:Vectorial product concentration obtained with a permeable immobilized enzyme membrane. A new approach to the analysis of biological transport systems. 375 38

The electrophoretic deposition of glucose oxidase from water using asymmetrical alternating voltages is investigated. Using asymmetric voltages, glucose oxidase layers with a thickness of 7 microm could be deposited on a platinum electrode in 20 min time as verified with a microbalance, carbon analysis and scanning electron microscopy. In contrast, if a symmetrical alternating signal is used under the same conditions, a layer of 0.5 microm is formed. We believe the deposition is due to two effects: the electrophoretic migration of the enzyme towards the deposition electrode and the pH induced precipitation of the enzyme near the deposition electrode. The electrophoretic migration is due to the non-linear dependence of the electrophoretic mobility on the electric field caused by the asymmetry of the applied alternating current signal. In addition, pH changes near the deposition electrode drive the enzyme towards its point of zero charge (PZC), perhaps causing the precipitation of GOx on the substrate. The effect of amplitude, frequency, deposition time and GOx concentration on the deposition rate was studied. An amplitude of 160 V(p-p) and a frequency of 30 Hz was found to be optimal for the formation of thick enzyme layers, which excludes a big part of the interferences.
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PMID:AC-electrophoretic deposition of glucose oxidase. 1962 78