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-(carbapentyl amino) butyric acid with a specific activity of 6.74 U/mg. By enhancing substrate affinity and catalytic efficiency of CgTaDH 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-(carbapentyl 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.