Artificial cofactor regenerating enzymes

Cofactor Substitution, Mediated Electron Transfer to Enzymes, Fig. 1 Examples of artificial cofactor regeneration and cofactor substitution used in in vitro enzyme catalysis. Cofaclor regeneration (middle) replaces the metabolic cofaclor regeneration found in vivo (top), while cofactor substitution (bottom) shortcuts the natural system and... 

Photosensitized regeneration of an oxidized cofactor, i.e. NAD(P)+ or a reduced cofactor NAD(P)H, could provide general routes for oxidative or reductive biocatalyzed photosynthetic transformations (see Sect. 3.2.3). Coupling of the regenerated NAD(P)+/NAD(P)H cofactors to enzymes that depend on these cofactors, opens a broad array of feasible photo-biocatalytic syntheses. An alternative approach to couple enzymes as catalysts for artificial photosynthetic... 

Figure 32. Photosensitized regeneration of NAD(P)H cofactor involving enzymes (FDR or LipDH) and the artificial electron-transfer mediator MV +, and using (A) Ru(bpy)j-" or (B) Zn(II) mMo-(A-tetramethylpyridinium)porphyrin, Zn-TMPyP +, as a photosensitizer.

Electrical Communication in Biocatalyzed Artificial Photosynthetic Systems. The various biocatalyzed photosynthetic systems discussed in Sections IV.C.l and IV.C.2 have applied diffusional electron carrier (native cofactors or synthetic electron mediators). For practical application of biocatalyzed photosynthetic systems, it is important to construct photosystems where the components are organized in an immobilized configuration that allows continuous regeneration of photochemical assembly. Yet the redox sites of enzymes do not communicate electrically with electron sources (or holes) located externally to the protein backbone (see Section IV.C). Thus construction of immobilized biocatalytic assemblies requires the development of nondiffusional means for electrical communication [92] between the enzyme redox site and the externally located excited species. 

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