title: Spectroscopic studies on the inhibitory effects of ionic liquids on lipase activity.
abstract: The effects of ionic liquids (ILs) on the lipase activity were studied by UV-Vis spectroscopy and the IL-lipase interaction mechanism at the molecular level was investigated by fluorescence technique. Experimental results indicated that the lipase activity was inhibited by ILs and the degree of inhibition highly depended on the chemical structures of ILs. The inhibitory ability of the Cl(-)- and Br(-)-based ILs increased with increasing the alkyl chain length in the IL cation. Thermodynamic parameters, enthalpy change (ΔH) and entropy change (ΔS) were obtained by analyzing the fluorescence behavior of lipase with the addition of ILs. Both ΔH and ΔS were positive suggesting hydrophobicity was the major driven force for the Cl(-)- and Br(-)-based ILs. For the BF4(-)-, CF3SO3(-)-, ClO4(-)- and N(CN)2(-)-based ILs, hydrogen bonding was the main driven force. For a more comprehensive understanding of the effects of ILs on lipase activity, the roles of hydrophobicity and hydrogen bonding must be considered simultaneously. A regression-based equation was developed to describe the relationship of the inhibitory ability of ILs and their hydrophobicity and hydrogen bonding ability.
authors.affiliation: College of Physics and Chemistry, Henan Polytechnic University, Jiaozuo 454003, China.
authors.forename: Yunchang
authors.initials: Y
authors.lastname: Fan
authors.affiliation: College of Physics and Chemistry, Henan Polytechnic University, Jiaozuo 454003, China.
authors.forename: Xing
authors.initials: X
authors.lastname: Dong
authors.affiliation: College of Physics and Chemistry, Henan Polytechnic University, Jiaozuo 454003, China.
authors.forename: Xiaojing
authors.initials: X
authors.lastname: Li
authors.affiliation: Technology Center of Ningbo Entry-Exit Inspection and Quarantine Bureau, Ningbo 315012, China.
authors.forename: Yingying
authors.initials: Y
authors.lastname: Zhong
authors.affiliation: College of Physics and Chemistry, Henan Polytechnic University, Jiaozuo 454003, China.
authors.forename: Jichuan
authors.initials: J
authors.lastname: Kong
authors.affiliation: College of Physics and Chemistry, Henan Polytechnic University, Jiaozuo 454003, China.
authors.forename: Shaofeng
authors.initials: S
authors.lastname: Hua
authors.affiliation: College of Physics and Chemistry, Henan Polytechnic University, Jiaozuo 454003, China. Electronic address: juanmiao2013@163.com.
authors.forename: Juan
authors.initials: J
authors.lastname: Miao
authors.affiliation: College of Physics and Chemistry, Henan Polytechnic University, Jiaozuo 454003, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Li
mesh_terms: D002175:Candida / Q000187:drug effects / Q000201:enzymology*; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000378:metabolism*; D006860:Hydrogen Bonding; D057927:Hydrophobic and Hydrophilic Interactions; D007093:Imidazoles / Q000737:chemistry / Q000378:metabolism; D052578:Ionic Liquids / Q000737:chemistry / Q000378:metabolism*; D008049:Lipase / Q000037:antagonists & inhibitors* / Q000378:metabolism; D011726:Pyridinium Compounds / Q000737:chemistry / Q000378:metabolism; D013050:Spectrometry, Fluorescence; D013816:Thermodynamics
chemical_list: D004791:Enzyme Inhibitors; D007093:Imidazoles; D052578:Ionic Liquids; D011726:Pyridinium Compounds; D008049:Lipase; C018100:1-methylimidazole
keywords: Fluorescence spectroscopy; Hydrogen bonding; Hydrophobicity; Ionic liquids (ILs); Lipase