Effects of deep eutectic solvents on the biotransformation efficiency of ω-transaminase

ω-transaminase (ω-TA) shows a significant promising in the synthesis of chiral amines. However, the poor activity of ω-TA in buffer water solution limits its application in industry, so green and economic methods adopted to improve ω-TA activity still face challenges. Here, deep eutectic solvents (DES) were used as the co-solvent to improve the catalytic activity of ω-TA. The results have shown that DES (ChCl: Urea 1:1) was the most suitable co-solvent for increasing the biotransformation efficiency of the ω-TA in nine different choline chloride-based DESs. The optimal enzymatic activity was achieved at 40 ℃, in 10 vol% DES and pH 8. The specific activity of ω-TA in DES was increased by 3.9 times due to the reinforced interactions between DES and enzyme. The kinetic analysis of transaminase showed that DES enhanced affinity of ω-TA for 1-(R)-PEA and pyruvate to increase by 1.93 and 1.63 times respectively compared with the control. Molecular docking shows that urea acted as a proton donor and a receptor during the enzymatic reaction, the docking binding energy increases to 3.21 and 3.59 kcal/mol, promoting the transamination reaction. DES can significantly improve the catalytic activity of ω-TA, which has broad development prospects in the field of green and efficient synthesis of pharmaceutical and natural product intermediates.