STUDY OF THE EFFECT OF IMIDAZOLE DERIVATIVE IONIC LIQUIDS ON LIPASE DYNAMICS AND STABILITY WITH MOLECULAR DYNAMICS SIMULATION METHOD Asep Iin Nur Indra, Rukman Hertadi, Reza Aditama
Bandung Institute of Technology
Abstract
Lipase is a potential enzyme for various catalysis reactions. In industry, lipase is commonly used in organic solvents environment so that its activity is increased. However, using organic solvents in the food and medical industries are very limited because of its volatile nature and high toxicity. Therefore, further research is developed using ionic liquids which can replace the role of organic solvents. Ion liquid has several advantages such as non-volatile, reusable and more environmentally friendly. In previous studies, it was known that imidazole derivative ionic liquids were reported to be able to increase lipase activity by 28.9%. However, the cause of the increase in activity was not yet known. This study aims to determine the stability of lipases in liquid ion derivatives of imidazole in silico. A lipase system with a water solvent and four imidazole derivative ionic liquids was prepared and a molecular dynamics simulation was carried out for 100 nanoseconds at 40 \( ^o C \) and 100 \( ^o C \). Simulation results show that lipase stability is thought to have a relationship with its catalytic activity. Lipase system with ionic liquid [EMIM]Br remains stable at 100 \( ^o C \) as indicated by an RMSD value of 2.9 Angstrom. From the results of the RMSF analysis it is known that the fluctuation of the lipase system with ionic liquid [EMIM]Br is maintained quite low but still maintains the mobility of the residue in the lid lipase area. The ionic liquid [EMIM]Br also surrounds lipase more than any other ionic liquid. It can be concluded that [EMIM]Br can stabilize the structure of proteins by protecting around lipases while maintaining the dynamics of the lid area. These results have provided information at the atomic level regarding the stability of lipases in various ionic liquids.
