Effect of acyl donors on EGCG esterification reaction catalyzed by Lipase "Amano" 30SD based on molecular dynamics analysis.

Enzymatic esterification of (-)-epigallocatechin gallate (EGCG) can improve its lipophilicity and promote its utilization, but acyl donors significantly affect the catalytic efficiency and selectivity of lipase in EGCG esterification. This study utilized food-grade Lipase "Amano" 30SD to catalyze the reaction between EGCG and different acyl donors. The yields and esterification sites of EGCG esterification products were analyzed using HPLC and MS. Molecular docking and molecular dynamics were used to further investigate the effect of acyl donor on catalytic efficiency and regioselectivity of Lipase "Amano" 30SD in EGCG esterification by establishing acyl-lipase models. Results showed that the yield of acetyl-EGCG was the highest (76.55 ± 3.45 %), while the selectivity of lauroyl-EGCG was the best with mono-substituted lauroyl-EGCG accounting for >80 %. Molecular dynamics and molecular docking revealed that acyl donors can enhanced the overall structural stability and active site flexibility of Lipase "Amano" 30SD, contributing to its catalytic efficiency. In acyl-Lipase "Amano" 30SD models, Gly122 can form H-bonds with the B-ring hydroxyl groups of EGCG, stabilizing the conformation of EGCG-Lipase "Amano" 30SD complexes to promote selective esterification of D-ring hydroxyl groups. This study promotes the understanding of enzymatic EGCG esterification and provides guidance for lipase catalytic selectivity and acyl donor selection.