Directed Evolution of AMDase to an Artificial Profen Racemase

The result of enzymatic decarboxylation was very clear. While (S)-6 resulted in a C-containing product (7), (R)-6 yielded a product with no more than occurs naturally. Apparently, the reaction proceeds with a net inversion of configuration. Thus, the presence of a planar intermediate (8) can be postulated. Enantioface-differentiating protonation to compound 8 will yield the optically active final product (7). 

6 DIRECTED EVOLUTION OF AMDase TO AN ARTIFICIAL PROFEN RACEMASE 

We recently succeeded in determining the three-dimensional (3D) structure of AMDase by X-ray crystallography [16]. AMDase is structurally similar to cofactor-independent amino acid racemases [17, 18]. Considering the similarities of ligand 

Glu racemase Asp racemase Hydantoin racemase Maleate isomerase AMDase 

TABLE 3.1 Reaction Specificity of AMDase and its Variant in Decarboxylation and Racemization 

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