Selectivity enzyme tuning

Directed Evolution - Enzyme Tuning Toward Higher Selectivity... 

When supported complexes are the catalysts, two types of ionic solid were used zeolites and clays. The structures of these solids (microporous and lamellar respectively) help to improve the stability of the complex catalyst under the reaction conditions by preventing the catalytic species from undergoing dimerization or aggregation, both phenomena which are known to be deactivating. In some cases, the pore walls can tune the selectivity of the reaction by steric effects. The strong similarities of zeolites with the protein portion of natural enzymes was emphasized by Herron.20 The protein protects the active site from side reactions, sieves the substrate molecules, and provides a stereochemically demanding void. Metal complexes have been encapsulated in zeolites, successfully mimicking metalloenzymes for oxidation reactions. Two methods of synthesis of such encapsulated/intercalated complexes have been tested, as follows. 

The apparent selective activation of genes responsible for induced odor production and the committed function of the resulting enzymes may allow for a precise fine tuning between insect-derived elicitors and the responses of the plant. Thus, plants have the potential to adapt their signals specifically to the insect that feeds on a plant. Several studies present evidence for such specificity. 

Owing to the influence of the medium, enzymes should feature different substrate specificities and selectivities than water. This would allow for tuning of these parameters under the control of the operator. 

Secondly, from the results so far obtained utilizing applied molecular evolution, it can be surmised that natural evolution of enzymes has been finely tuned to select for... 

For example, parameters such as transducer type and pretreatment, enzyme and mediator concentration and their rahos within the film, type of immobihzation matrix, immobihzation parameters, and film thickness are varied. A rahonal optimization approach includes that the main parameters affecting the overah ET pathway and hence the final sensor response have to be investigated in order to find reasonable tools for tuning the performance of the selected biosensor design. 

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