1. Introduction
During the last years laccase/mediator systems have been proposed for the regeneration of NAD(P)+-dependent enzymatic processes in synthetic applications [1,2]. These initial studies showed a high potential for up-scaling, but more detailed investigationsarenecessarytounderstandthestrengthsandweaknesses of these regeneration systems. In this work we studied the underlying principles for an efficient and stable enzymatic regeneration process of NAD(P)+, which does not show the restrictions of alternative systems, e.g. electrochemical methods [3]. Coenzymes are costly [4], which makes them too expensive to employ more than the minimal amount that still guarantees fast conversion of the synthetic enzyme [5]. High costs have been an obstacle in the widerapplicationofcoenzyme-dependentoxidreductases,butthis is also the strongest argument for applying efficient and economical coenzyme regeneration systems. Various methods such as chemical,biological,photochemical,electrochemicalorenzymatic approaches have been suggested and reviewed for this purpose [6,7]. Among them, the enzymatic methods seem to be the most convenient and useful. Such in situ regeneration reactions have been used in a number of oxidoreductase-catalyzed reactions, and some of them have been up-scaled to large-scale syntheses [1]. As suggested by Chenault and Whitesides [8] an ideal enzymatic regeneration system should meet the following criteria: (i) the enzymes should be inexpensive and stable, (ii) the enzymes should have high specific activity, (iii) simple and inexpensive reagents that do not interfere with the isolation of the product of interest or with enzyme stability should be employed, (iv) high turnover numbers should be obtained, (v) the total turnover number of the coenzyme should be at least between 102 and 104, and (vi) an overall equilibrium for the coupled enzyme system favorable to product formation should be reached. These criteria have been already partially met for NAD+-reducing enzymes
http://dx.doi.org/10.1016/j.molcatb.2015.06.011
1. บทนำDuring the last years laccase/mediator systems have been proposed for the regeneration of NAD(P)+-dependent enzymatic processes in synthetic applications [1,2]. These initial studies showed a high potential for up-scaling, but more detailed investigationsarenecessarytounderstandthestrengthsandweaknesses of these regeneration systems. In this work we studied the underlying principles for an efficient and stable enzymatic regeneration process of NAD(P)+, which does not show the restrictions of alternative systems, e.g. electrochemical methods [3]. Coenzymes are costly [4], which makes them too expensive to employ more than the minimal amount that still guarantees fast conversion of the synthetic enzyme [5]. High costs have been an obstacle in the widerapplicationofcoenzyme-dependentoxidreductases,butthis is also the strongest argument for applying efficient and economical coenzyme regeneration systems. Various methods such as chemical,biological,photochemical,electrochemicalorenzymatic approaches have been suggested and reviewed for this purpose [6,7]. Among them, the enzymatic methods seem to be the most convenient and useful. Such in situ regeneration reactions have been used in a number of oxidoreductase-catalyzed reactions, and some of them have been up-scaled to large-scale syntheses [1]. As suggested by Chenault and Whitesides [8] an ideal enzymatic regeneration system should meet the following criteria: (i) the enzymes should be inexpensive and stable, (ii) the enzymes should have high specific activity, (iii) simple and inexpensive reagents that do not interfere with the isolation of the product of interest or with enzyme stability should be employed, (iv) high turnover numbers should be obtained, (v) the total turnover number of the coenzyme should be at least between 102 and 104, and (vi) an overall equilibrium for the coupled enzyme system favorable to product formation should be reached. These criteria have been already partially met for NAD+-reducing enzymeshttp://dx.doi.org/10.1016/j.molcatb.2015.06.011
การแปล กรุณารอสักครู่..
