Lipase-catalyzed Reaction Research Articles

Remarkable acceleration of a lipase-catalyzed reaction by a thiacrown ether additive: buffer-free highly regioselective partial hydrolysis of 4-acetoxy-2-methylbut-2-enyl acetate

The reaction efficiency of the lipase-catalyzed partial hydrolysis of 4-acetoxy-2-methylbut-2-enyl acetate is greatly enhanced by the presence of 5 mol% of a thiacrown ether, particularly remarkable improvement being observed in CRL- and PCL-catalyzed reactions. 4-Hydroxy-2-methylbut-2-enyl acetate has thus been simply prepared by buffer-free lipase-catalyzed hydrolysis.

A kinetic study of candida rugosa lipase-catalyzed synthesis of 4,6-dimethyl-3-cyano-2-pyridone

The synthesis of 4,6-dimethyl-3-cyano-2-pyridone was studied in a reaction catalyzed with Candida rugosa lipase. A response surface methodology (RSM) was applied for the optimization of the experimental conditions. The study showed that temperature and molar ratio cyanoacetamide/acetylacetone have a great influence on the yield of the reaction; the maximum yield was achieved at 44 ºC with a molar ratio cyanoacetamide/acetylacetone of 36. The kinetics of the enzymatic synthesis of 4,6-dimethyl-3-cyano-2-pyridone was investigated, and it was determined that a ping-pong bi-ter mechanism with cyanoacetamide inhibition fits the obtained results. The mechanism of lipase-catalyzed reaction was proposed.

Kinetic resolutions of amine and thiol analogues of secondary alcohols catalyzed by the Candida antarctica lipase B

Chiral amine and thiol analogues of secondary alcohols were tested as substrates for the Candida antarctica lipase B with emphasis on lipase enantioselectivity and substrate reactivity. Although the apparent enantiomeric ratios were lower for the amines than for the corresponding alcohols, the amines 2-octylamine and 1-phenyl-ethylamine were produced with high optical purity (ee-93–99%) in a lipase-catalyzed acyl transfer reaction with ethyl octanoate as the acyl donor. The initial rates were lower and the reaction times longer for the amines than for the corresponding alcohols. The thiols 2-octanethiol and 1-phenylethanethiol did not yield any thiol ester product in the analogous lipase-catalyzed acyl transfer reaction. By preparing the thiooctanoate of 1-phenyl-ethanethiol and employing it as acyl donor in a lipase-catalyzed reaction with 1-phenylethanol as acyl acceptor, however, 1-phenylethanethiol could be resolved with high enantiomeric excess of the ( R)-enantiomer (ee-95%) and moderate enantiomeric excess of the ( S)-enantiomer (ee-75%).

Enzymes in polymer chemistry, 9. Polymerizable oligoesters from cholic acid via lipase catalyzed condensation reactions

AbstractRegioselective oligocondensation of cholic acid in the 3‐position was achieved in organic solution in the presence of a lipase from Candida antarctica. Furthermore, a mixture of cholic acid, 11‐methacryloylaminoundecanoic acid and the lipase resulted in the production of a radically polymerizable oligo(cholic acid ester) bearing exactly one methacrylic end group. This new monomer was polymerized radically yielding the corresponding comb‐polymers bearing several cholic acid esters at the end of the side chains.

Simple preparation of optically pure bis(trifluoromethyl)-alkanediols through lipase-catalyzed reaction

Enantioselective hydrolysis of diacetate of bis(trifluoromethyl)alkanediols has been demonstrated. Candida antarctica lipase was chosen from among commercial enzymes as the one most able to enantioselectively hydrolyze the acetyl group giving optically pure diols and diacetate.

Lipase-catalysed kinetic resolution of ethyl D,L-2-amino-4-phenylbutyrate by hydrolysis

Of 25 commercial lipases, nine were able to catalyse the hydrolysis of ethyl D,L-2-amino-4-phenylbutyrate (D,L-APBAE) to optically active D-APBAE, an intermediate for the synthesis of inhibitors of angiotensin-converting enzyme, with specific selectivity ranging between 3.7 and 12.5. Optimal conditions for porcine pancrease lipase-catalyzed reaction gave a 68% conversion and the D-ester was obtained by a simple extraction with an optical purity of 98%. Saponification of the ethyl ester of D-APBA in 1 M NaOH gave the optically active D-APBA with a chemical purity greater than 99%.

Adsorption of protein from several commercial lipase preparations onto a hollow-fiber membrane module.

Ten commercially available crude preparations of lipase from various microbial sources were adsorbed from aqueous buffers at several initial concentrations onto a bundle of hydrophobic hollow fibers made of poly(propylene) at pH 7.0 and 40 degrees C. The kinetics of adsorption were evaluated from measurements at various times of the protein content of the supernatant solution (using BSA as equivalent) in a well-mixed reservoir placed in series with the hollow fiber module. Preliminary tracer experiments have indicated that the module and the tank can be simulated as a system consisting of a plug flow reactor in series with a continuous stirred tank reactor. A mechanistic model based on the hydrodynamic assumptions associated with this system coupled with the postulation of two reversible first-order steps for the adsorption of protein was successfully fitted to the experimental data via nonlinear regression analysis. The statistical significance of the model was checked using tests for lack of fit. This work is useful in predicting the time period required to immobilize a (crude) lipase by adsorption onto a hydrophobic hollow fiber module, a configuration which has proved successful in the recent past for the performance of lipase-catalyzed reactions.

Microwave-Promoted Lipase-Catalyzed Reactions. Resolution of (+/-)-1-Phenylethanol.

Microwave irradiation increased enzymatic affinity and selectivity of supported lipases in esterification and transesterification reactions carried out in dry media and at temperature near 100 degrees C.

Occurrence of estolides in processed Dimorphotheca pluvialis seed oil

Samples of oil from Dimorphotheca pluvialis processed by extraction and mechanical expelling were analyzed using supercritical fluid chromatography (SFC), lipase-catalyzed reactions, and 1H-NMR. SFC analysis detected the occurrence of free fatty acid, diglycerides, and unknown materials having molecular weights equivalent to four and five acyl groups. These components were present in larger quantities for oils recovered via mechanical expelling. Results from lipase-catalyzed reactions and NMR analysis suggest the large molecular weight molecules are triglycerides containing additional acyl groups through estolide bonds. The chemical shifts of the olefinic protons on the conjugated double bonds of dimorphecolic [D(+)-18:2 10 t,12 t -OH 9] acid and its estolides appeared at higher ppm values when compared to non-conjugated olefinic absorptions.

Ultrasound-promoted lipase-catalyzed reactions

Lipase from porcine pancreas is first demonstrated to catalyze reactions under ultrasonic condition. Reaction rates are significantly enhanced 7 to 83-fold and enantioselectivities are retained.

光学活性医薬品の触媒的不斉合成研究

A new designing concept, "Respective Control Concept, "for developing highly efficient chiral bisphosphines ligands has been proposed. On the basis of our concept, new chiral bisphosphine ligands, BCPM, MCCPM, MOD-BPPM, MOD-DIOP, MOD-Degphos, MOC-BIMOP, Cy-BIMOP, etc., have been synthesized. Their rodium complexes have been formed and found to show high catalytic activity and enantioselectivity in the asymmetric hydrogenation of prochiral carbonyl and olefinic compounds leading to the practical synthesis of chiral aminoalcohols, α-amino acid derivatives and succinic acid derivatives. Furthermore, asymmetric synthesis of chiral 1, 4-dihydropyridines, barbiturates, and glycerol derivatives was realized using lipase-catalyzed reactions in organic solvents. The lipase PS mutant (FVL) was indicated to show the same hydrolytic behavior as that of lipase AH.

光学分割剤としてのリパーゼと基質の相性診断

Recently, lipases are used widely as reagents for syntheses of chiral compounds, although organic chemists have only a little knowledge about characteristics of individual lipases. Reactivities and selectivities of lipase-catalyzed reactions are reviewed from a viewpoint of organic syntheses in the present article, which will be usefull for a guide to the proper selection of a lipase for kinetic resolutions of racemic compounds.

Lipase-promoted asymmetric transesterification of 4-alkyloxetan-2-ones with ring-opening

Lipase-catalysed reaction of (±)-4-alkyloxetan-2-ones 1a–c with benzyl alcohol gave (R)-1a(R = Me)(36%, 96% ee) and benzyl (S)-3-hydroxybutanoate 2a(51%, 85% ee), (R)-1b(R = Pr)(42%, 75% ee) and benzyl (S)-3-hydroxyhexanoate 2b(45%, 69% ee) and (S)-1c(R = Pri, 41%, 95% ee) and benzyl (R)-3-hydroxy-4-methylpentanoate 2c(43%, 90% ee), respectively.

Biotechnology of lipids: The use of lipases for the structural modification of fats and oils

The food industry has introduced chemical and enzymatic procedures for the modification of fats and oils to allow the improvement of their organoleptic and/or nutritional properties. As chemical procedures have many drawbacks, the application of enzyme technology shows as a promising approach for the development of new fats and oil-derived products. Lipase-catalyzed interesterification reactions allow the structural modification of lipids by selectively changing the composition of a triacylglycerol under very mild and controlled conditions. This work reviews the main characteristics of lipase reactions, the use of lipases for interesterification procedures, and the advantages and limitations of lipase immobilization for the enzymatic modification of fats and oils. The use of lipases from different sources for fat splitting and the potential application of stereospecific lipases for the production of structured or designer lipids is also discussed.

An improved procedure for chemospecific acylation of 2-mercaptoethanol by lipase-catalyzed transesterification

Various O-acyl derivatives of 2-mercaptoethanol have been obtained enzymatically by lipase-catalyzed chemospecific esterification reactions of the substrate and several aliphatic carboxylic acid ethyl esters.

Synthesis of New Chiral Building Blocks via an Enzymatic Reaction : A New Method of Enhancing Enantioselectivity of the Enzymatic Reaction

This review describes efficient means of preparing optically pure compounds via bakers' yeast mediated reaction or lipase-catalyzed reaction : (1) Bakers' yeast mediated reaction of cyanoketone was demonstrated and was discovered a new type of C-C bond forming reaction. (2) Hydrolysis of 2-substituted-3-acetoxy esters by Aspergillus lipase (lipase A 6) was demonstrated. According to summarize the stereo favoritism between substrates, the active site model of an Aspergillus lipase is proposed. (3) A simple preparation of optically active α- or γ-hydroxystannanes using Pseudomonas lipase (lipase PS) was realized. (4) Two effective means were discovered for enantioselective reaction of lipase PS : one is the modification of the acyl group by a sulfur functional group and the other is addition of a catalytic amount of l-methioninol or crown ether derivatives to the reaction mixture. (5) Optically pure (R) -4-hydroxy-3- (3, 4-methylenedioxyphenyl) methylbutanenitrile, obtained by this reaction, was applied to the synthesis of three anti-tumor lignans. (6) As a new chiral building block for tertiary alcohols, (R) -2-ally1-2- (phenylthio) methyloxirane was synthesized via lipase-catalyzed reaction.

Lipase-catalyzed reactions in vesicles as an approach to vesicle self-reproduction.

As a continuation of our endeavor to find conditions under which bounded aggregate structures are able to self-reproduce, we have investigated the reactivity of lipase, both in free solution and vesicle-entrapped, against mixed oleic acid/oleate/ethyl oleate vesicles. Three types of vesicles have been prepared and characterized: (A) oleic acid/oleate vesicles; (B) oleic acid/oleate/ethyl oleate vesicles; and (C) lipase containing oleic acid/oleate vesicles. Long time stability studies by quasi elastic light scattering show that whereas (B) and (C) vesicles remain stable with a diameter of 110-130 nm and monodisperse for over a period of one month, vesicles (A) separated from an initial single population of 105 nm diameter into two populations, having respectively 70 nm diameter (more than 95% of the particles) and 180-210 nm diameter (less than 5% of the total population). In the case of vesicles (C), it could be shown that the enzyme remains localized inside the vesicles and it does not protrude into the water bulk phase. The enzymatic hydrolysis of ethyl oleate (which is water-insoluble) incorporated in the B-vesicles was studied under two configurations: (I) by adding lipase externally to the B-vesicles; (II) by mixing vesicles (B) and vesicles (C). In both cases, the reaction progressed to 100% hydrolysis. In the first case, the reaction was attended by an increase of the number of vesicles, and since this hydrolysis reaction takes place within the boundary of the parent vesicles, the criteria of autopoietic self-reproduction of vesicles are satisfied. In the case (II) instead, no increase of the population number of particles could be detected. The possible reasons for this difference are discussed.

Rapid, sensitive fluorometric determination of serum triglyceride by measuring lipase-liberated fatty acids

A continuous fluorescence displacement assay was developed for the measurement of long-chain fatty acids and utilized in the study of triglyceride lipase-catalyzed reactions (Wilton, DC. Biochem J 1991;276:129-33). We now describe a method for the rapid measurement of triglyceride in serum with the fluorescence displacement assay. The method involves the hydrolysis of a diluted sample equivalent to 0.1 microL of original serum with excess lipase (EC 3.1.1.3) from Rhizopus arrhizus and measuring the fatty acid released after a set time interval, normally 1 min. Under the conditions of the timed assay, about 2 mol of fatty acid are released per mole of triglyceride. The released fatty acid is monitored by fluorescence change and is proportional to the concentration of triglyceride in the original serum sample. The effective range of serum triglyceride concentration that could be measured was 0.5-10 mmol/L (0.44-8.8 g/L), based on triolein standard. The assay is unique in that it measures lipase-liberated fatty acids rather than liberated glycerol and as such is not subject to many of the criticisms of the glycerol-based methods. Comparison of fasted serum samples established a high correlation between the fatty acid and glycerol methods.

Lipase-catalysed esterification reaction in a tubular reactor

Lipozyme catalysed esterification of oleic acid with lauryl alcohol was studied in a tubular recycle reactor. Water formed during the reaction was removed by adsorption, either by passing the product mixture through another column packed with molecular sieve, or by packing the reactor partially with silica gel.

Preparation of a new chiral building block for synthesizing broadly varied types of tertiary alcohols

Preparation of chiral phenyl glycidyl sulfide 1, which is a useful chiral building block for tertiary alcohol derivatives, is achieved via lipase-catalyzed reaction as a key step.