Anhydrous Organic Solvents Research Articles

Reformulated Kinetics of Immobilized Enzymes in Non-Conventional Media: A Case of Lipase-Catalyzed Esterification

Several approaches have been reported that aim to achieve simplified standardizations of the kinetic behavior of immobilized enzymes under specific experimental conditions. We have previously published simplified rate equations based on the kinetics of immobilized enzymes. Recently, new experimental results have become available on the kinetics and mechanisms of esterifications catalyzed by immobilized lipase in unconventional media, and consequently, a reformulation of their kinetics is necessary. In this work, we report the development of simplified rate equations relating the aforementioned reaction conditions on a new basis, considering our kinetic and mechanistic results. We provide experimental evidence that two different mechanisms describe the esterifications catalyzed by immobilized lipase, either in anhydrous organic solvent (n-hexane) or under non-solvent conditions. A ping-pong bi–bi mechanism with double dead-end substrate inhibition by both the fatty acid and the alcohol has been found to apply in the former case, while in the latter case the esterification proceeds via an ordered bi–bi mechanism with single dead-end substrate inhibition by ethanol. This study may be biotechnologically useful, as the increased use of immobilized enzymes, whether in academic research or in industry, requires sustainable development of new and environmentally friendly synthetic processes.

Hydrophobic Surfactant-DNA Complex (Surf-DNA) Enables DNA-Encoded-Library-Compatible Decarboxylative Arylation under Anhydrous Conditions.

DNA-encoded libraries (DELs) are a key technology for identifying small-molecule hits in both the pharmaceutical industry and academia, but their chemical diversity is largely limited to water-compatible reactions to aid in the solubility and integrity of encoding DNA tags. To broaden the DEL chemical space, we present a workflow utilizing DNA-cationic surfactant complexation that enables dissolution and reactions on-DNA in anhydrous organic solvents. We demonstrate its utility by developing DEL-compatible photoredox decarboxylative C(sp2)-C(sp3) coupling under water-free conditions. The workflow is optimized for the 96-well format necessary for large-scale DEL productions, and it enables screening and optimization of DEL-compatible reactions in organic solvents.

A direct alkylation of resorcinols

Alkylation of resorcinol and methyl-substituted resorcinols and its methyl ethers with alkyl bromides in water and anhydrous organic solvents led to mono- and/or dialkylated resorcinols and alkyl cyclohexendiones, depending on the structure of the starting substrates and reaction conditions. Selective di-alkylation was achieved in both, aqueous and anhydrous conditions, up to 76% yield. Resorcinol monomethyl ethers behaved similarly to phenols, giving in dry organic solvents predominantly ortho -substituted products, and a mixture of ortho- and para-substituted products together with resorcinol ethers in aqueous solution. The alkylation of 2,4,6-trimethyl resorcinol monomethyl ether showed selective 2 C-alkylation in 53% yield. 2-Methyl resorcinol with electrophiles in excess afforded in tetra-alkylation up to 72% yield.

Stereospecific and selective enzymatic resolution of carboxylic acid derivatives in organic solvents

Enzymes such as lipases and proteases have been used as catalysts in nearly anhydrous organic solvents such as diisopropyl ether and hexane to carry out stereospecific and selective enzymatic resolutions of carboxylic acid derivatives such as 2-bromohexadecanoic acid, which may be used for prevention and treatment of bone loss-related diseases and β-phenyllactic acid, which has a role as a human metabolite.

Rational Design for Enhanced Acyltransferase Activity in Water Catalyzed by the Pyrobaculum calidifontis VA1 Esterase.

Biocatalytic transesterification is commonly carried out employing lipases in anhydrous organic solvents since hydrolases usually prefer hydrolysis over acyl transfer in bulk water. However, some promiscuous acyltransferases can catalyze acylation in an aqueous solution. In this study, a rational design was performed to enhance the acyltransferase selectivity and substrate scope of the Pyrobaculum calidifontis VA1 esterase (PestE). PestE wild type and variants were applied for the acylation of monoterpene alcohols. The mutant PestE_I208A is selective for (–)-menthyl acetate (E-Value = 55). Highly active acyltransferases were designed, allowing for complete conversion of (–)-citronellol to citronellyl acetate. Additionally, carvacrol was acetylated but with lower conversions. To the best of our knowledge, this is the first example of the biocatalytic acylation of a phenolic alcohol in bulk water. In addition, a high citronellol conversion of 92% was achieved with the more environmentally friendly and inexpensive acyl donor ethyl acetate using PestE_N288F as a catalyst. PestE_N288F exhibits good acyl transfer activity in an aqueous medium and low hydrolysis activity at the same time. Thus, our study demonstrates an alternative synthetic strategy for acylation of compounds without organic solvents.

Biosynthesis of a Novel Antibacterial Dipeptide, Using Proteases From South American Native Fruits, Useful as a Food Preservative.

Antiacanthain and granulosain are the partially purified proteolytic extracts from the South American native fruits of Bromelia antiacantha (Bertol. ) and Solanum granuloso leprosum, respectively. The aim of this work was to compare the ability of both soluble and immobilized antiacanthain and granulosain f or the synthesis of Z-Tyr-Val-OH, a novel antibacterial dipeptide, in different reaction systems formed by almost anhydrous organic solvents (Xw: 1 × 10−5) and several percentages of immiscible organic solvents in 100 mM Tris(hydroxymethyl)aminomethane hydrochloride buffer pH 8.0. Soluble antiacanthain in half of the 24 different organic biphasic media showed higher catalytic potential than in 100 mM Tris(hydroxymethyl)aminomethane hydrolchloride buffer pH 8.0. Soluble granulosain showed lower catalytic potential in all liquid-liquid biphasic media than in the same buffer. However, 50% (v/v) ethyl ethanoate in 100 mM Tris(hydroxymethyl)aminomethane hydrolchloride buffer pH 8.0 allowed to express the highest catalytic potential of both soluble enzymes. In 50% v/v ethyl ethanoate, soluble antiacanthain and granulosain catalyzed the synthesis of Z-Tyr-Val-OH with 72 ± 0.15 and 60 ± 0.10% maximal peptide yields, respectively. Multi-point immobilization in glyoxyl-silica did not lead to better peptide yields than soluble enzymes, in that liquid-liquid biphasic medium under the same reaction conditions. Soluble and glyoxyl-silica immobilized antiacanthain in almost anhydrous ethyl ethanoate (Xw: 1 × 10−5) were able to retain 17.3 and 45% of the initial proteolytic activity of antiacanthain in 100 mM Tris hydrolchloride buffer pH 8.0, respectively, at 40°C under agitation (200 rpm). Soluble and glyoxyl-silica immobilized granulosain were inactivated under the same reaction conditions. Glyoxyl-silica immobilized antiacanthain showed to be a robust biocatalyst in almost anhydrous ethyl ethanoate (Xw: 1 × 10−5), eliciting the best peptide yield (75 ± 0.13%). The synthesis reaction of Z-Tyr-Val-OH could not proceed when soluble antiacanthain was used under the same conditions. Both peptidases only catalyzed the synthesis reaction under kinetic control, using activated acyl donor substrates. Finally, this work reports a novel broad-spectrum antibacterial peptide that significantly decreased (p ≤ 0.05) the specific growth rates of Gram positive and Gram negative microorganisms at very low concentrations (≥15 and 35 μg/ml, respectively); contributing with a new safe food preservative of applying for different food systems.

Dinuclear Zn Complex: Phenoxyl Radical Formation Driven by Superoxide Coordination

AbstractThe dinuclear zinc complex Zn2L2 (HL=2‐{[[di(2‐pyridyl)methyl](methyl)amino]methyl}phenol) has been synthesized and isolated as colorless crystals. The interaction of the compound with superoxide in anhydrous organic solvents has been evaluated by CV, stopped‐flow Uv‐vis, EPR and ESI‐MS suggesting the binding and the activation of the coordinated superoxide, thanks to the Lewis acidity of the Zn(II) centers. The results obtained in this study highlight the formation of a Zn2L2−O2.− intermediate and a metastable phenoxyl‐radical driven by the coordinated superoxide.

Fabrication of microneedle patches with lyophilized influenza vaccine suspended in organic solvent.

Skin vaccination by microneedle (MN) patch simplifies the immunization process to increase access to vaccines for global health. Lyophilization has been widely used to stabilize vaccines and other biologics during storage, but is generally not compatible with the MN patch manufacturing processes. In this study, our goal was to develop a method to incorporate lyophilized inactivated H1N1 influenza vaccine into MN patches during manufacturing by suspending freeze-dried vaccine in anhydrous organic solvent during the casting process. Using a casting formulation containing chloroform and polyvinylpyrrolidone, lyophilized influenza vaccine maintained activity during manufacturing and subsequent storage for 3months at 40°C. Influenza vaccination using these MN patches generated strong immune responses in a murine model. This manufacturing process may enable vaccines and other biologics to be stabilized by lyophilization and administered via a MN patch.

Eco-friendly Synthesis of Nanoporous Magnesium by Air-Free Electrolytic Dealloying with Recovery of Sacrificial Elements for Energy Conversion and Storage Applications

The synthesis of nanoporous Mg with minimal surface oxide coverage has been hindered by its high chemical reactivity. Herein, we demonstrate the fabrication of three-dimensional bicontinuous nanoporous Mg with ligament and pore sizes in the range of 20–30 nm using air-free electrolytic dealloying with recovery of the sacrificial material. The starting material consists of a magnesium–lithium parent alloy with lithium as the sacrificial component. During selective electrolytic leaching in an anhydrous lithium-conducting organic electrolyte solvent, the sacrificial lithium is stripped from the magnesium–lithium parent alloy used as the working electrode and plated on a pure lithium foil used as the counter electrode, enabling sacrificial element recovery, making the process eco-friendly. The morphology of the fabricated nanoporous Mg was thoroughly investigated using electron microscopy techniques, inductively coupled plasma (ICP) spectroscopy, X-ray photoelectron spectroscopy (XPS), small-angle X-ray scattering (SAXS), and X-ray diffraction. The synthesized nanoporous Mg is attractive for energy conversion and storage applications. Here, we show that it can produce hydrogen on-demand by hydrolysis with pure water and that it can also be used as a high-capacity lithium-ion battery anode.

Eco-Friendly Synthesis of Nanoporous Magnesium By Air-Free Electrolytic Dealloying of Magnesium-Lithium Alloy with Recovery of Sacrificial Lithium

In recent years, air- and water-sensitive nanostructured materials with minimal surface oxide coverage have received increased attention for their potential role in various applications, such as catalysts for combustion fuels, active ingredients in solid-propellant rockets, and reactants for onboard and on-demand hydrogen generation to feed fuel cells. However, the fabrication of this class of materials has been hindered by their inherently high chemical reactivity. Magnesium, with its standard reduction potential of -2.37 V vs. SHE, is highly water-reactive in its nanostructured form, thus the synthesis of nanostructured magnesium with minimal surface oxide coverage poses a challenge. In this talk, I will introduce a novel eco-friendly air-free selective electrolytic leaching route to fabricate three-dimensional (3D) bicontinuous nanoporous magnesium (NP-Mg) with minimal surface oxide coverage. The starting material consists of a Mg-Li parent alloy, with lithium as the sacrificial component. During selective electrolytic leaching in an anhydrous lithium-conducting organic electrolyte solvent, the sacrificial lithium is stripped from the Mg-Li parent alloy used as the working electrode and plated on a pure lithium foil used as the counter electrode. This process enables sacrificial element recovery, making it eco-friendly. The dealloyed NP-Mg exhibits a characteristic ligament and pore size in the range of 20-30 nm, and its morphology was thoroughly investigated using electron microscopy, inductively coupled plasma (ICP) spectroscopy, small-angle X-ray scattering (SAXS), and X-ray diffraction, as will be shown during my talk. NP-Mg with such ultra-small feature size could be attractive for several applications including hydrogen storage in the form of magnesium hydride, and on-demand hydrogen generation by hydrolysis with pure water.

Pegylation of RNA Spiegelmers by a Novel Widely Applicable Two-Step Process for the Conjugation of Carboxylic Acids to Amino-Modified Oligonucleotides.

The reaction between N-hydroxy succinimide (NHS) ester-activated carboxylic acids and amino-modified nucleic acids is commonly used for the post-synthetic modification of oligonucleotides. Here, we report a two-step variation of the method in which the NHS ester is replaced by the corresponding parent carboxylic acid. In the first step, the carboxylic acid is activated with a standard peptide coupling reagent like HBTU in an anhydrous water-miscible aprotic organic solvent. In the second step, the solution of the activated carboxylic acid is added to the amino-modified oligonucleotide in water. The method is demonstrated using 40-kDa polyethylene glycol (PEG) carboxylic acid and biotin as examples. Recycling of the carboxylic acid, which is typically used in molar excess over the nucleic acid, is shown for the conjugation with 40-kDa PEG carboxylic acid. This conjugation method is generally applicable to the conjugation of carboxylic acids to amino-modified oligonucleotides, thus enabling the attachment of small to large molecular entities such as dyes, tags, peptides, and other macromolecules. © 2020 Wiley Periodicals LLC. Basic Protocol 1: General protocol for the conjugation of an amino-modified oligonucleotide with a carboxylic acid, exemplified for 40-kDa PEG carboxylic acid Basic Protocol 2: Biotinylation of an amino-modified oligonucleotide using the general conjugation protocol Basic Protocol 3: Recycling of the carboxylic acid component from the conjugation reaction, demonstrated for 40-kDa PEG carboxylic acid using ultrafiltration Support Protocol 1: Analytical AEX-HPLC method used as in-process control method to monitor the conjugation reaction with 40-kDa PEG carboxylic acid Support Protocol 2: Analytical AEX-HPLC method used as in-process control method to monitor the conjugation reaction with biotin Support Protocol 3: Analytical IP-RP-HPLC method used as in-process control method to monitor the conjugation reaction Alternate Protocol: Separation of 40-kDa PEG carboxylic acid from unreacted and conjugated oligonucleotide by preparative AEX-HPLC.

Expression of engineered carbonyl reductase from Ogataea minuta in Rhodococcus opacus and its application to whole-cell bioconversion in anhydrous solvents

The carbonyl reductase from the methylotrophic yeast Ogataea minuta can catalyze the regio- and enantio-selective reduction of prochiral ketones to chiral alcohols, and is available for industrial manufacturing of statin drugs. We previously conducted a directed evolution experiment of the enzyme, and obtained a mutant (OCR_V166A) with improved tolerance to organic solvents. This expanded the applicability of the enzyme to the bioconversion of water-insoluble compounds (Honda etal., J. Biosci. Bioeng., 123, 673-678, 2017). In the present study, we expressed OCR_V166A in Rhodococcus opacus cells, which have a highly lipophilic surface structure and are dispersible in anhydrous organic solvents, and developed a whole-cell biocatalyst which can function in an organic-solvent-based reaction medium. The secondary alcohol dehydrogenase from Thermoanaerobacter ethanolicus (TeADH) was employed as an NADPH-regenerating enzyme and co-expressed with OCR_V166A in R. opacus. The whole-cell bioconversion of 2,2,2-trifluoroacetophenone to α-(trifluoromethyl)benzyl alcohol was performed in organic solvents, including isopropanol, isobutanol, and cyclohexanol, which served both as reaction media and as substrates for TeADH. The type of organic solvents markedly affected not only the product titer but also the enantio-purity of the product. When isobutanol was used as the reaction medium, the whole-cell biocatalyst showed higher stability than the isolated enzyme. Consequently, a high concentration (1M) of the substrate was converted to the product with an overall conversion yield of 81% (mol/mol) in 24h.

ChemInform Abstract: Water Opens the Door to Organolithiums and Grignard Reagents: Exploring and Comparing the Reactivity of Highly Polar Organometallic Compounds in Unconventional Reaction Media Towards the Synthesis of Tetrahydrofurans.

It has always been a firm conviction of the scientific community that the employment of both anhydrous conditions and water-free reaction media is required for the successful handling of organometallic compounds with highly polarised metal–carbon bonds. Herein, we describe how, under heterogeneous conditions, Grignard and organolithium reagents can smoothly undergo nucleophilic additions to γ-chloroketones, on the way to 2,2-disubstituted tetrahydrofurans, “on water”, competitively with protonolysis, under batch conditions, at room temperature and under air. The reactivity of the above organometallic reagents has also been investigated in conventional anhydrous organic solvents and in bio-based eutectic and low melting mixtures for comparison. The scope and limitations of this kind of reaction are discussed.

Stable aqueous dispersions of optically and electronically active phosphorene

Understanding and exploiting the remarkable optical and electronic properties of phosphorene require mass production methods that avoid chemical degradation. Although solution-based strategies have been developed for scalable exfoliation of black phosphorus, these techniques have thus far used anhydrous organic solvents in an effort to minimize exposure to known oxidants, but at the cost of limited exfoliation yield and flake size distribution. Here, we present an alternative phosphorene production method based on surfactant-assisted exfoliation and postprocessing of black phosphorus in deoxygenated water. From comprehensive microscopic and spectroscopic analysis, this approach is shown to yield phosphorene dispersions that are stable, highly concentrated, and comparable to micromechanically exfoliated phosphorene in structure and chemistry. Due to the high exfoliation efficiency of this process, the resulting phosphorene flakes are thinner than anhydrous organic solvent dispersions, thus allowing the observation of layer-dependent photoluminescence down to the monolayer limit. Furthermore, to demonstrate preservation of electronic properties following solution processing, the aqueous-exfoliated phosphorene flakes are used in field-effect transistors with high drive currents and current modulation ratios. Overall, this method enables the isolation and mass production of few-layer phosphorene, which will accelerate ongoing efforts to realize a diverse range of phosphorene-based applications.

Aci-Quinone Compounds from Eugenoxyacetic Acid and Methyleugenol: Preparation and Reaction

A new aci-quinone compound, 4-(aci-nitro)-2-(methoxy)-5-(3-nitro-2-(nitrooxy)propyl)-cyclohexa-2,5- dienone (2), an analog to 4-(aci-nitro)-2-(carboxymethoxy)-5-(3-nitro-2-(nitrooxy)propyl)-cyclohexa-2,5-dienone (1), was successfully synthesized and fully characterized by spectroscopic methods. The reactions of 1 and 2 with various reagents such as hydroxylamine, acetic anhydride, semicarbazide and thiosemicarbazide were examined. The structure of 11 obtained new compounds was established by IR, 1H NMR, 13C NMR, HMBC and MS spectra. It was shown that the unstable, sensitive aci-quinone structure of compounds 1 and 2 can exist in anhydrous organic solvents such as AcOEt, EtOH but in the presence of water, H+, HO- or at high temperatures, the aci-quinone structure of both 1 and 2 tendentiously transformed into the more stable nitro-phenol form. Keywords: Aci-nitro, aci-quinone, nitrophenol, eugenol, semicarbazone, thiosemicarbazone.

(Invited) Solution Processing and Device Integration of Two-Dimensional Black Phosphorus

Two-dimensional black phosphorus (2D BP) has emerged as a promising candidate for next-generation electronics and optoelectronics. As is common for new materials, much of the early work on 2D BP has focused on measuring and optimizing intrinsic properties on small samples under idealized conditions. However, real-world devices and systems inevitably require large-area samples that are integrated with dielectrics, contacts, and other semiconductors at standard temperature and pressure conditions. These requirements are particularly challenging to realize for 2D BP since its properties are highly sensitive to surface chemistry, defects, and the surrounding environment. This talk will thus explore methods for improving the uniformity of solution-based 2D BP with an eye toward realizing scalable processing of large-area thin-films. Specifically, methods for exfoliating black phosphorus in anhydrous organic solvents will be discussed such that the resulting 2D BP flakes show field-effect transistor mobilities and on/off ratios that are comparable to micromechanically exfoliated flakes [1]. In addition to solution processing, this talk will also report on the integration of 2D BP with dielectrics and other materials. In particular, atomic layer deposition of alumina dielectrics on 2D BP suppresses ambient degradation, thereby preserving electronic properties in field-effect transistors at atmospheric pressure conditions [2]. [1] J. Kang, J. D. Wood, S. A. Wells, J.-H. Lee, X. Liu, K.-S. Chen, and M. C. Hersam, “Solvent exfoliation of electronic-grade, two-dimensional black phosphorus,” ACS Nano, DOI: 10.1021/acsnano.5b01143 (2015). [2] J. D. Wood, S. A. Wells, D. Jariwala, K.-S. Chen, E. Cho, V. K. Sangwan, X. Liu, L. J. Lauhon, T. J. Marks, and M. C. Hersam, “Effective passivation of exfoliated black phosphorus transistors against ambient degradation,” Nano Lett., 14, 6964 (2014).

Polymerization Induced Self-Assembly of Alginate Based Amphiphilic Graft Copolymers Synthesized by Single Electron Transfer Living Radical Polymerization.

Alginate-based amphiphilic graft copolymers were synthesized by single electron transfer living radical polymerization (SET-LRP), forming stable micelles during polymerization induced self-assembly (PISA). First, alginate macroinitiator was prepared by partial depolymerization of native alginate, solubility modification and attachment of initiator. Depolymerized low molecular weight alginate (∼12 000 g/mol) was modified with tetrabutylammonium, enabling miscibility in anhydrous organic solvents, followed by initiator attachment via esterification yielding a macroinitiator with a degree of substitution of 0.02, or 1-2 initiator groups per alginate chain. Then, methyl methacrylate was polymerized from the alginate macroinitiator in mixtures of water and methanol, forming poly(methyl methacrylate) grafts, prior to self-assembly, of ∼75 000 g/mol and polydispersity of 1.2. PISA of the amphiphilic graft-copolymer resulted in the formation of micelles with diameters of 50-300 nm characterized by light scattering and electron microscopy. As the first reported case of LRP from alginate, this work introduces a synthetic route to a preparation of alginate-based hybrid polymers with a precise macromolecular architecture and desired functionalities. The intended application is the preparation of micelles for drug delivery; however, LRP from alginate can also be applied in the field of biomaterials to the improvement of alginate-based hydrogel systems such as nano- and microhydrogel particles, islet encapsulation materials, hydrogel implants, and topical applications. Such modified alginates can also improve the function and application of native alginates in food and agricultural applications.

Solvent exfoliation of electronic-grade, two-dimensional black phosphorus.

Solution dispersions of two-dimensional (2D) black phosphorus (BP)--often referred to as phosphorene--are achieved by solvent exfoliation. These pristine, electronic-grade BP dispersions are produced with anhydrous organic solvents in a sealed-tip ultrasonication system, which circumvents BP degradation that would otherwise occur via solvated O2 or H2O. Among conventional solvents, N-methylpyrrolidone (NMP) is found to provide stable, highly concentrated (∼0.4 mg/mL) BP dispersions. Atomic force microscopy, scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy show that the structure and chemistry of solvent-exfoliated BP nanosheets are comparable to mechanically exfoliated BP flakes. Additionally, residual NMP from the liquid-phase processing suppresses the rate of BP oxidation in ambient conditions. Solvent-exfoliated BP nanosheet field-effect transistors exhibit ambipolar behavior with current on/off ratios and mobilities up to ∼10(4) and ∼50 cm(2) V(-1) s(-1), respectively. Overall, this study shows that stable, highly concentrated, electronic-grade 2D BP dispersions can be realized by scalable solvent exfoliation, thereby presenting opportunities for large-area, high-performance BP device applications.

Synthesis and Characterization of Organo-Inorganic Nanoobjects Based on Hyperbranched Polyethoxysiloxanes

The synthetic scheme for obtaining modified molecular silicasols based on hyperbranched polyethoxysiloxane (HPEOS) is presented in this work. The synthetic scheme includes several stages; the first and most important one represents polycyclization and simultaneous modification of HPEOS with either organosilanols or disiloxanes. The following stages are polymer-analogous reactions affecting only the external layer. The obtained nanoparticles are nanogels with specific morphology of inorganic silica core soluble in anhydrous organic solvents. All the hybrid systems were characterized by means of elemental analysis, GPC, IR and NMR spectroscopy. Some physical and chemical parameters were determined for all samples after fractionation. Synthesized molecular silicasols are ready-made universal models for investigations of interactions between macromolecules of polymer matrix and nanoparticles, and evaluation of various factors, such as the chemical nature of the external layer or particle core size, which have a great influence upon properties of nanocomposites.

Aqueous-Level Turnover Frequency of Lipase in Organic Solvent

In this work, we explored the activation of a lipoprotein lipase from Burkholderia sp. by surfactants, sugars, and sugar–surfactant combinations for enhancing its activity in organic solvent. The lipase was most strongly activated by the combination of dextrin and anionic surfactant 1. As a result, its turnover frequency in anhydrous toluene reached 420 s–1, which was comparable to its aqueous counterpart. It was also found that a glucosamine-headed surfactant 8 as a molecular mimic of the dextrin-1 combination enhanced the turnover frequency of LPL to the aqueous level. As a rationale for such a high turnover frequency of lipoprotein lipase in anhydrous organic solvent, we speculate that the dextrin-1 couple or its mimic 8 could provide an efficient water-mimicking hydrogen bonding network around the enzyme in addition to the contribution as the oil surrogate, thus leading to a large increase of active enzyme molecules.