Engineering Tauriopine Dehydrogenase for Efficient Catalytic Synthesis of (R)‐Alpha‐Ethyl‐2‐Oxo‐1‐Pyrrolidineacetic Acid

The synthetic pathway for Etiracetam depends on alpha‐ethyl‐2‐oxo‐1‐pyrrolidineacetic acid (AEOPA) as a crucial intermediate. This paper presents an enzymatic synthesis approach for producing ( R )‐AEOPA. Through database mining, we discovered a tauriopine dehydrogenase capable of catalyzing the reaction between γ‐aminobutyric acid and 2‐oxobutyric acid, resulting in the synthesis of ( R )‐4‐(carboxypropylamino) butyric acid with a specific activity of 6.74 U/mg. By enhancing substrate affinity and catalytic efficiency of Cg TaDH through protein engineering, we achieved a 5.9‐fold increase in enzyme activity compared to the wild type. Further optimization led to a space‐time yield (STY) of 3.95 g/L/h for ( R )‐4‐(carboxypropyl amino) butyric acid and a high yield of 73.0 % for the final product, ( R )‐AEOPA. This study demonstrates a novel synthesis method for ( R )‐AEOPA and highlights the potential of biocatalysis in improving the production of Etiracetam through successful enzymatic processes.