Synergetic Activation of Lipase by an Amino Acid with Alkyl–PEG Sulfate Ionic Liquid

Abstract

The synergetic effect of amino acids and an ionic liquid, 1-butyl-2,3-dimethylimidazolium ¡-cetylpolyoxyethylene(10) ether sulfate (IL1), as coating materials on lipase was discovered: coating on lipase PS using a certain amino acid with IL1 was found to be very effective for accelerating the lipase-catalyzed transesterification of secondary alcohols while maintaining perfect enantioselectivity.Lipases are among the most widely used enzymes applicable for various substrates; however, the reaction rate and enantioselectivity depend significantly on both the substrates and reaction media: the reaction rates are generally dependent on the reaction media, and very slow or poorly enantioselective reactions are sometimes obtained. 1We have been investigating enzymatic reactions in the ionic liquid (IL) solvent system and have established that various types of ILs are applicable as solvents for biochemical reactions. 24 We further developed a powerful method for the activation of lipase protein through coating with an ionic liquid: Burkholderia cepacia lipase coated with the ionic liquid, 1-butyl-2,3-dimethylimidazolium ¡-cetylpolyoxyethylene(10) ether sulfate (IL1), 5,6 (IL1-PS), displayed excellent reactivity for many substrates in conventional organic solvents 5 and ionic liquids. 7Luo and co-workers reported the preparation of chiral imidazolium salts derived from proline. 8 Inspired by their work, we prepared two types of chiral pyrrolidine-substituted imidazolium ¡-cetylpolyoxyethylene(10) ether sulfate, and found that (R)-3-butyl-2-methyl-1-(pyrrolidin-2-ylmethyl)-1H-imidazol-3-ium ¡-cetylpolyoxyethylene(10) ether sulfate (D-ProMe) derived from D-proline worked as an excellent activating agent for lipase PS (Figure 1). 9 An extraordinary acceleration was accomplished with perfect enantioselectivity for the D-ProMe-PS-catalyzed reaction, and a reaction 58 times faster (vs. lipase PS) was recorded.9 However, more simple coating materials need to be developed for the activation of lipase. We herein report the synergetic activation of amino acids and IL1 as a coating material for lipase.Amino acids have been used as stabilizers of enzymes during the purification process. For example, commercial lipase PS contains ca. 20 wt % glycine as an essential stabilizer during the preparation of the lipase protein through the lyophilization process. 5b We investigated the role of glycine and established that it worked only as a stabilizer of the enzyme and had no influence on the reactivity of lipase PS. 5b Since it was anticipated that a chiral amino acid may modify the enantioselectivity of an enzymatic reaction, we next prepared amino acidcoated lipase PS and investigated its properties in the transesterification of («)-1-phenylethanol (1a) as a model substrate in the presence of vinyl acetate as an acyl donor in the i-Pr 2 O solvent system (Figure 2). 10 As shown in Figure 2, the coating of lipase PS with amino acids neither accelerated the reaction nor modified its enantioselectivity, although coating lipase with L-asp...

Mammalian blood odorant and chirality: synthesis and sensory evaluation by humans and mice of the racemate and enantiomers of trans-4,5-epoxy-(E)-2-decenal

“…17 Lipase PS was a remarkably suitable enzyme to give (2S,3R)-4-t-butyldimethylsilyloxy-2,3-epoxybutyl acetate (98% ee) from the corresponding racemic alcohol by enzymatic asymmetric acetylation with vinyl acetate. 18 In the present case with (±)-4 however, lipase PS coated with an ionic liquid [IL 1:a-cetylpolyoxyethylene (19)ether sulfate] 19 could not discriminate the enantiomers of 4, and after only 4 h at room temperature, (±)-4 furnished the corresponding racemic acetate (±)-6 in 95% yield (Scheme 2). The enzymatic route was therefore abandoned.…”

Ionic Liquid-Mediated Activation of Lipase-Catalysed Reaction

“…[20] MALD-TOF Mass experiments suggested that IL1 binds with the enzyme protein; therefore, it was assumed that the modified activity of lipase might be due to flexibility or conformation change of the lipase protein caused by the IL1-binding. [21] Furthermore, it was established that imidazolium cation affected the enantioselectivity of the lipase; IL1-coated lipase PS gave better enantioselectivity than an IL2coated one. [20] Amino acids have been used as a stabilizer of an enzyme during the purification process: commercial lipase PS involves ca.…”

Benzoate Surfactants for Enhancing the Activity of Lipoprotein Lipase from Burkholderia Species in Organic Solvent

“…They include the immobilization of enzymes on solid supporters [6][7][8][9][10][11][12] and the use of additives such as inorganic salts, [13][14][15][16][17] ionic liquids, [18][19][20][21][22] or surfactants. They include the immobilization of enzymes on solid supporters [6][7][8][9][10][11][12] and the use of additives such as inorganic salts, [13][14][15][16][17] ionic liquids, [18][19][20][21][22] or surfactants.…”