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1.
J Oleo Sci ; 69(10): 1231-1240, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33028752

RESUMO

The bioavailability of DHA-bound phospholipids, especially the DHA-bound lysophospholipid (DHA-LPL) could be considered the most effective DHA chemical forms for DHA accretion in the brain. Such a DHA-LPL should also have very high emulsifying stability performance based on its analogy with conventional soy LPL. Therefore, in this study, we describe two fishery byproducts, rich in DHA-bound phospholipids, to derive DHA-LPL via sn-1 positional specific lipase partial hydrolysis of the phospholipids. Through this reaction, the DHA composition increased to 43.8 % from 29.1 % in the salmon head phospholipid-derived DHA-LPL, and to 84.0 % from 47.4 % in the squid meal phospholipid-derived DHA-LPL. In fact, these obtained DHA-LPLs exhibited far higher emulsifying stability than the conventional food emulsifiers in the market. For example, the prepared high-purity squid meal phospholipid-derived LPL sustained an emulsion form for a week even under 80°C. Thus, food emulsifiers produced from fishery byproducts are considered to exhibit very high values of both in a sense of outstandingly high health benefits and sustaining emulsions even under very high temperatures.


Assuntos
Ácidos Docosa-Hexaenoicos/química , Ácidos Docosa-Hexaenoicos/isolamento & purificação , Emulsificantes/química , Emulsificantes/isolamento & purificação , Produtos Pesqueiros/análise , Alimento Funcional , Lisofosfolipídeos/química , Lisofosfolipídeos/isolamento & purificação , Estabilidade de Medicamentos , Temperatura Alta , Hidrólise , Lipase/química
2.
Sheng Wu Gong Cheng Xue Bao ; 36(8): 1556-1567, 2020 Aug 25.
Artigo em Chinês | MEDLINE | ID: mdl-32924354

RESUMO

Improving the thermal stability of enzymes is a hot and difficult point in the field of biocatalysis. Compared with the traditional directed evolution, computational assisted rational design is more efficient, and is widely used in enzyme engineering. Using Bacillus subtilis LipA as the model protein, the structure cavity of the enzyme was analyzed by Rosetta-VIP design, the mutation which was beneficial to the filling of the structure cavity (ΔΔE<0) was selected, followed by the solvent accessible surface area and evolutionary conservation analysis. The thermal stabilities of six out of sixteen designed single-point mutants were improved, with a maximum ΔTm value of 3.18 °C. These six mutations were further used for iterative combination mutation, the maximum ΔTm of the two-point and three-point combination mutants were 4.04 °C and 5.13 °C, respectively. The Tm of the four-point combination mutant M11 (F17A/L114P/I135V/M137L) was increased by 7.30 °C. The Tm of the six-point combination mutant M10 (F17A/V74I/L114P/I135V/M137A/I157L) was increased by 7.43 °C. The thermal stability of mutation with lower energy value, reduced accessible surface area, while conformed to evolutionary conservatism, was more likely to be improved. Therefore, the multiple virtual screening strategy based on the enzyme structure cavity filling, solvent accessible surface area and amino acid sequence conservation analysis can effectively improve the thermal stability of enzyme.


Assuntos
Bacillus subtilis , Biologia Computacional , Estabilidade Enzimática , Lipase , Bacillus subtilis/enzimologia , Bacillus subtilis/genética , Lipase/química , Lipase/genética , Lipase/metabolismo , Mutação
3.
J Oleo Sci ; 69(8): 893-905, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32759550

RESUMO

In this study, lipase from Thermomyces lanuginosus (TLL) was immobilized onto the parent and organic groups modified SBA-15, and the enzymatic properties of the obtained immobilized TLL samples were investigated. 1) Activity of SBA-15-TLL at 2862.78 ± 293.24 U/g was obtained. 2) Most of the organic groups modification favored a great improvement in activity, and higher activity over 12000 U/g was observed for N-phenylaminomethyl and phenyl group modification. 3) Most of the supported TLL showed better thermostability in air while poor in phosphate buffer, with over 80% vers less than 20% of their initial activity retained after 4 h incubation at 70℃. 4) The n-dodecyl, phenyl and N-phenylaminomethyl group functionalization decreased the sensitivity of immobilized TLL in extreme pH values. 5) The n-octyl and 2-(propoxymethyl)oxirane group modification confered the supported TLL good reusability, and over 60% of their initial activity was retained after five successive cycles of reuse.


Assuntos
Ascomicetos/enzimologia , Enzimas Imobilizadas/química , Lipase/química , Dióxido de Silício/química , Estabilidade Enzimática , Óxido de Etileno/química , Concentração de Íons de Hidrogênio , Fenômenos de Química Orgânica , Espaço Pessoal , Fosfatos
4.
J Oleo Sci ; 69(7): 727-735, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32612022

RESUMO

Petroleum based phthalate plasticizers encounter enormous claims to prohibit their production due to their harmful health impacts when they are mixed with plastics. That is why efforts are being done to find safer natural alternatives. We have investigated the reaction kinetics of the esterification epoxidation of oleic acid and 2-ethylhexanol in the presence of hydrogen peroxide catalyzed using Candida antarctica lipase (Novozym 435, Novozymes, Kobenhavn, Denmark). The product of this reaction is epoxidized 2-ethylhexyl oleate, a non-phthalate green plasticizer. The kinetic model for this reaction follows a multi-substrate PingPong Bi-Bi mechanism with competitive inhibition by the alcohol. The reaction's kinetic parameters were found to be 0.76 M, 0.37 M, 0.08 M, and 37.20 mM/min for Michalis-Menten constant for oleic acid (Kmo), Michalis-Menten constant for alcohol (Kma), alcohol inhibition constant (Kia), and maximum reaction velocity (Vmax), respectively. Then the Gibbs function analysis of the transition state based on the Arrhenius and Eyring equations was carried out. The internal diffusional limitations were found to be negligible as the effectiveness factor took the value of almost unity. While the external mass transfer resistance had no effect on the reaction due to operating at relatively high agitation speed and high temperature. This investigation confirms that this reaction was only kinetically controlled.


Assuntos
Técnicas de Química Sintética , Lipase/química , Ácidos Ftálicos , Plastificantes/síntese química , Aldeídos/química , Candida/enzimologia , Catálise , Esterificação , Cinética , Ácido Oleico/química , Fenômenos de Química Orgânica
5.
J Oleo Sci ; 69(7): 737-742, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32612023

RESUMO

Esterification of D-glucose with oleic- and palmitic acids were carried out in the absence and presence of a biocatalyst, Candida antarctica lipase. The reaction medium was a mixture of dimethyl sulphoxide and tert-butanol (1:4, v/v). The reaction products were analysed by FTIR, 1H-NMR and 13C-NMR, HSQC, and by ESI-MS. Results indicated that the ester products formed were 6-O-glucose oleate and 6-O-glucose palmitate both in the absence and in the presence of the biocatalyst, with yields above 90%.


Assuntos
Biocatálise , Ésteres/síntese química , Glucose/química , Ácido Oleico/síntese química , Ácidos Oleicos/química , Palmitatos/síntese química , Ácidos Palmíticos/química , terc-Butil Álcool/química , Dimetil Sulfóxido/química , Esterificação , Proteínas Fúngicas/química , Lipase/química
6.
J Oleo Sci ; 69(8): 825-835, 2020 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-32641606

RESUMO

The development of human milk fat substitutes (HMFSs), rich in palmitic acid (16:0) at the sn-2 position of triacylglycerol (TAG) and rich in unsaturated fatty acids (FAs) (oleic acid, 18:1 and linoleic acid, 18:2) at the sn-1(3) positions, has gained popularity. In this study, HMFSs containing polyunsaturated fatty acids (PUFAs) predominantly at the sn-2 position were prepared, and their oxidation stabilities were compared. First, a non-PUFA-containing HMFS (NP-HMFS) was produced by enzymatic reactions using Novozyme® 435 and Lipozyme® RM-IM as the enzymes and lard as the raw material. Second, HMFSs, containing 10 % PUFA at the sn-2 or sn-1(3) position, were individually prepared by enzymatic reactions using lard and fish oil as raw materials. Here, sn-2-PUFA-monoacylglycerol (MAG) was extracted from the reaction solution using a mixture of hexane and ethanol/water (70:30, v/v) to produce high-purity sn-2-PUFA-MAG with 78.1 % yield. For the PUFA-containing HMFS substrates, comparable oxidation stability was confirmed by an auto-oxidation test. Finally, HMFSs containing 10 % or 2 % sn-1,3-18:1-sn-2-PUFA-TAG species were prepared by enzymatic reactions and subsequent physical blending. The oxidative stability of sn-1,3-18:1-sn-2-PUFA-HMFS was two-fold higher than that of 1/2/3-PUFA-HMFS in which each PUFA was located without stereospecific limitations in TAG. The removal of PUFA-TAG molecular species with higher concentrations of unsaturated units had a significant effect. In addition, the oxidation stability increased with the addition of tocopherol as an antioxidant. Thus, the combined use of two strategies, that is, the removal of PUFA-TAG molecular species with high concentrations of unsaturated units and the addition of antioxidants, would provide a PUFA-containing HMFS substrate with high oxidative stability.


Assuntos
Substitutos da Gordura/química , Ácidos Graxos Insaturados/química , Ácidos Graxos Insaturados/isolamento & purificação , Leite Humano , Triglicerídeos/química , Triglicerídeos/isolamento & purificação , Antioxidantes , Gorduras na Dieta , Óleos de Peixe/química , Humanos , Ácido Linoleico , Lipase/química , Ácido Oleico , Oxirredução , Ácido Palmítico , Tocoferóis
7.
J Oleo Sci ; 69(8): 907-912, 2020 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-32641616

RESUMO

D-ribose-oleic acid esters were produced with or without a biocatalyst, using in the same organic media, dimethyl sulfoxide (DMSO): tert-butanol (TBU) or 2-methyl-2-butanol (2M2B). The yield of the ester product was above 90% in both of the reactions. The biocatalyst used was lipase B of Candida antarctica. Molecular characterization was performed by using all the analytical methods available: IR, 1H-NMR and 13C-NMR, HSQC, and ESI-MS.


Assuntos
Biocatálise , Ésteres/síntese química , Proteínas Fúngicas/química , Lipase/química , Ácidos Oleicos/síntese química , Ribose/síntese química , Dimetil Sulfóxido/química , Esterificação , Ésteres/química , Ácidos Oleicos/química , Pentanóis/química , Ribose/química , terc-Butil Álcool/química
8.
Food Chem ; 333: 127528, 2020 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-32682231

RESUMO

Endogenous lipase and lipoxygenase play important roles in accelerating lipid oxidation. Polyphenols are a series of commonly used chemicals for preserving fish and seafood products, due to their positive inhibitory effects on lipid oxidation. However, the mechanism involved is still unknown. The inhibitory effects of chlorogenic acid (CGA) on lipase and lipoxygenase were investigated and explored with multi- spectroscopic and molecular docking approaches. Results showed that CGA could inhibit the activities of lipase and lipoxygenase with concentration increased in a highly dose-dependent manner. CGA quenched intrinsic fluorescence intensities of enzymes by static quenching and binding with CGA which led to changes in 3D structures of enzymes. Results of the molecular docking confirmed binding modes, binding sites and major interaction forces between CGA and enzymes, which reduced the corresponding activity. Thus, this study could provide basic mechanisms of the inhibitory effects of polyphenols on lipid oxidation during food preservation.


Assuntos
Ácido Clorogênico/metabolismo , Ácido Clorogênico/farmacologia , Metabolismo dos Lipídeos/efeitos dos fármacos , Inibidores de Lipoxigenase/metabolismo , Inibidores de Lipoxigenase/farmacologia , Simulação de Acoplamento Molecular , Animais , Sítios de Ligação , Conservação de Alimentos , Lipase/antagonistas & inibidores , Lipase/química , Lipase/metabolismo , Lipoxigenase/química , Lipoxigenase/metabolismo , Oxirredução/efeitos dos fármacos , Polifenóis/farmacologia , Espectrometria de Fluorescência
9.
Int J Nanomedicine ; 15: 2935-2945, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32425525

RESUMO

Background: New anticancer agents that rely on natural/healthy, not synthetic/toxic, components are very much needed. Methods: Ricinoleyl hydroxamic acid (RHA) was synthesized from castor oil and hydroxylamine using Lipozyme TL IM as a catalyst. To optimize the conversion, the effects of the following parameters were investigated: type of organic solvent, period of reaction, amount of enzyme, the molar ratio of reactants and temperature. The highest conversion was obtained when the reaction was carried out under the following conditions: hexane as a solvent; reaction period of 48 hours; 120 mg of Lipozyme TL IM/3 mmol oil; HA-oil ratio of 19 mmol HA/3 mmol oil; and temperature of 40°C. The cytotoxicity of the synthesized RHA was assessed using human dermal fibroblasts (HDF), and its application towards fighting cancer was assessed using melanoma and glioblastoma cancer cells over a duration of 24 and 48 hours. Results: RHA was successfully synthesized  and it demonstrated strong anticancer activity against glioblastoma and melanoma cells at as low as a 1 µg/mL concentration while it did not demonstrate any toxicity against HDF cells. Conclusion: This is the first report on the synthesis of RHA with great potential to be used as a new anticancer agent.


Assuntos
Antineoplásicos/síntese química , Antineoplásicos/farmacologia , Óleo de Rícino/química , Neoplasias Encefálicas/tratamento farmacológico , Neoplasias Encefálicas/patologia , Catálise , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Fibroblastos/efeitos dos fármacos , Glioblastoma/tratamento farmacológico , Glioblastoma/patologia , Hexanos/química , Humanos , Hidroxilamina/química , Lipase/química , Lipase/metabolismo , Melanoma/tratamento farmacológico , Melanoma/patologia , Solventes/química
10.
PLoS One ; 15(4): e0231177, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32271820

RESUMO

Enrichment of omega-3 fatty acids (É·-3 FAs) in natural oils is important to realize their health benefits. Lipases are promising catalysts to perform this enrichment, however, fatty acid specificity of lipases is poor. We attempted to improve the fatty acid selectivity of a lipase from Geobacillus thermoleovorans (GTL) by two approaches. In a semi-rational approach, amino acid positions critical for binding were identified by docking the substrate to the GTL and best substitutes at these positions were identified by site saturation mutagenesis followed by screening to obtain a variant of GTL (CM-GTL). In the second approach based on rational design, a variant of GTL was designed (DM-GTL) wherein the active site was narrowed by incorporating two heavier amino acids in the lining of acyl-binding pocket to hinder access to bulky É·-3 FAs. The affinities DM-GTL with designed substrates were evaluated in silico. Both, CM-GTL and DM-GTL have shown excellent ability to discriminate against the É·-3 FAs during hydrolysis of oils. Engineering the binding pocket of an enzyme of a complex substrate, such as a triglyceride, by incorporating the information on substrate structure and computationally derived binding modes, has resulted in designing two efficient lipase variants with improved substrate selectivity.


Assuntos
Ácidos Graxos Ômega-3/metabolismo , Geobacillus/enzimologia , Lipase/metabolismo , Engenharia de Proteínas , Sequência de Aminoácidos , Aminoácidos/metabolismo , Domínio Catalítico , Simulação por Computador , Concentração de Íons de Hidrogênio , Hidrólise , Lipase/química , Lipase/isolamento & purificação , Metilação , Modelos Moleculares , Proteínas Mutantes/análise , Proteínas Mutantes/química , Mutação/genética , Dobramento de Proteína , Especificidade por Substrato , Temperatura
11.
Food Chem ; 318: 126482, 2020 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-32145543

RESUMO

We have examined the trans-resveratrol/lipase interaction by quantitative and qualitative analyses of fluorescence spectra, molecular docking and quantum-chemical calculations at DFT level. Interactions of CpLIP2 from C. parapsilosis CBS 604 and trans-resveratrol were confirmed with a major contribution of tryptophan residues to fluorescence quenching. A thermodynamic study across a wide temperature range was consistent with the presence of a single binding site with a binding free energy of -24 kJ/mol. Nevertheless, trans-resveratrol competitively inhibited CpLIP2 activity. Molecular docking and quantum-chemical calculations were consistent with a strong binding of trans-resveratrol to the CpLIP2 catalytic site via electrostatic and hydrophobic forces. The structural analysis quantitatively revealed an energy transfer from W51 and W350 to trans-resveratrol with a distance of 32 Å. Precise understanding of trans-resveratrol/CpLIP2 interactions has important implications on lipases for screening of stilbenoid.


Assuntos
Candida parapsilosis/enzimologia , Lipase/metabolismo , Resveratrol/metabolismo , Sítios de Ligação , Domínio Catalítico , Simulação por Computador , Inibidores Enzimáticos/química , Inibidores Enzimáticos/metabolismo , Inibidores Enzimáticos/farmacocinética , Fluorescência , Proteínas Fúngicas/química , Proteínas Fúngicas/metabolismo , Lipase/antagonistas & inibidores , Lipase/química , Simulação de Acoplamento Molecular , Resveratrol/química , Resveratrol/farmacocinética , Termodinâmica
12.
World J Microbiol Biotechnol ; 36(3): 45, 2020 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-32130535

RESUMO

Entrapment of halloysite nanotubes (HNTs) loaded with enzyme, into a polymer matrix (PVA/Alg), is a way to produce an environment surrounding the adsorbed enzyme molecules which improves the enzyme properties such as storage and operational stability. Hence, in this study, we optimised the factors affecting lipase adsorption onto halloysite nanotubes including halloysite amounts (5, 42.5 and 80 mg), lipase concentrations (30, 90 and 150 µg/ml), temperatures (5, 20 and 35 °C) and adsorption times (30, 165 and 300 min). The optimal conditions were determined as an halloysite amount of 50 to 80 mg, a lipase concentration of 30 to 57 µg/ml, an adsorption temperature of 20 °C and an adsorption time of 165 min, which resulted in a specific activity and adsorption efficiency of 15,000 (U/g protein) and 70%, respectively. Then, lipase adsorbed under optimal conditions was entrapped in a PVA/Alg hydrogel. The formation mechanism of immobilized lipase was investigated by FESEM and FTIR. Subsequent entrapment of adsorbed lipase improved the lipase storage and operational stability. Km, Vmax, Kcat and Kcat/Km values showed an increase in the entrapped HNT-lipase performance in comparison with the free and adsorbed lipase.


Assuntos
Argila/química , Lipase/química , Álcool de Polivinil/química , Adsorção , Candida/enzimologia , Estabilidade Enzimática , Enzimas Imobilizadas/química , Nanotubos
13.
Arch Microbiol ; 202(6): 1497-1506, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32219482

RESUMO

Lipases with high tolerance to temperature play a significant role in industry from food manufacturing to waste management systems. Thus, there is a need to investigate these enzymes from different geographical areas to look out for a more thermo-stable one. Characterization of lipases through experimental approaches is time consuming process and sometimes the results are ambiguous due to errors. However, integration of computational technologies is quite useful for prediction of optimized conditions. Such technologies can be applied as synthetic biology, which has many major applications in engineered biological approaches for accurate prediction of effects of different physical and chemical parameters on the system. In this study, cloning and expression of a lipase gene from Bacillus amyloliquefaciens, isolated from a novel geographical region of Pakistan, in Escherichia coli DH5α cells followed by sequencing was carried out. To isolate thermostable lipase producing strains, all the samples were kept at 50 °C. Genomic DNA was isolated and signal peptide (1-32 residues) sequence was chopped (ΔSPLipase). The ΔSPLipase was amplified and expressed in Linearized p15TV-L vector. The purified lipase appeared as single band of approximately 26 kDa. Suitable conditions of factors required for maximum lipase activity such as temperature, pH, substrate, organic solvent, detergents and metal ions were predicted through synthetic biology approach and further confirmed in wet lab. The predicted suitable factors for enzyme were almost similar to those determined experimentally. The optimum enzyme activity was recorded at pH 8 and 50 °C temperature. Interestingly, the activity of enzyme was found on a number of solvents, metal ions, detergents, and surfactants. The predicted optimum values and their experimental confirmations highlights the importance of integrated synthetic biology approaches in wet lab experiments. The characterized lipase of B. amyloliquefaciens at molecular level from Pakistani strains displayed good activity on a range of factors that implies this strain to be used for application in industrial level production.


Assuntos
Bacillus amyloliquefaciens/enzimologia , Bacillus amyloliquefaciens/metabolismo , Proteínas de Bactérias/metabolismo , Lipase/metabolismo , Bacillus amyloliquefaciens/genética , Bacillus amyloliquefaciens/isolamento & purificação , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Clonagem Molecular , Estabilidade Enzimática , Escherichia coli/genética , Escherichia coli/metabolismo , Concentração de Íons de Hidrogênio , Lipase/química , Lipase/genética , Paquistão , Solventes , Especificidade por Substrato , Biologia Sintética , Temperatura
14.
Food Chem ; 318: 126518, 2020 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-32151925

RESUMO

Cocoa butter substitutes (CBS) used for chocolate preparation was produced using a mixture of palm kernel oil (PKO) and enzymatically interesterified fats. The interesterified fats consisted of palm olein (POL), fully hydrogenated palm oil (FHPO) and PKO that were catalyzed using Lipozyme TL IM at 65 °C in a solvent-free packed bed reactor. An interesterification degree of 97.10% was obtained using feed flow rate of 70 mL/min and the interesterified fats showed steep solid fat content (SFC) curve characteristics with low SFC at high temperature. In the binary system, PKO and the interesterified fats showed good compatibility at 5-10 °C, while eutectic effects were observed at 15-35 °C. CBS produced from PKO and the interesterified fats in a mass ratio of 4:6 (CBS-46) and 3:7 (CBS-37) had crystals formed prominently in the ß' form. Without the need of a tempering process, chocolate made using CBS-46 as the base oil exhibited the desired properties in terms of hardness and fracturability.


Assuntos
Chocolate , Gorduras na Dieta , Indústria de Processamento de Alimentos/métodos , Óleo de Palmeira/química , Catálise , Esterificação , Gorduras/química , Indústria de Processamento de Alimentos/instrumentação , Lipase/química
15.
Carbohydr Polym ; 234: 115914, 2020 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-32070532

RESUMO

In this work, ionic liquids-modified magnetic carboxymethyl cellulose nanoparticles (IL-MCMC) were prepared and used as supports for enzyme immobilization. The specific activity of immobilized lipase PPL-IL-MCMC was 1.43 and 2.81 folds higher than that of free PPL and PPL-MCMC, respectively. Water contact angle analysis indicated that the introduction of ionic liquids increased the hydrophobicity of supports, which in tune induced the lid-opening of lipase, allowing its active sites to become more accessible. In addition, the affinity between lipase and substrate immobilized on the prepared supports was enhanced. The same method was also applied to analyze immobilize penicillin G acylase (PGA) to further investigate the general applicability of the method. The results showed that the immobilized PGA exhibited higher stability than many other reported PGAs. The developed composites may be utilized as excellent supports for enzyme immobilization in industrial application.


Assuntos
Celulose/metabolismo , Líquidos Iônicos/metabolismo , Lipase/metabolismo , Nanopartículas de Magnetita/química , Animais , Biocatálise , Celulose/química , Enzimas Imobilizadas/química , Enzimas Imobilizadas/metabolismo , Líquidos Iônicos/química , Lipase/química , Estrutura Molecular , Pâncreas/enzimologia , Tamanho da Partícula , Propriedades de Superfície , Suínos
16.
Molecules ; 25(3)2020 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-32028723

RESUMO

The Amano lipase from Pseudomonas fluorescens (L-AK) was covalently immobilized on various carbon nanomaterials (functionalized single-walled carbon nanotubes and graphene oxide) and tested for biodiesel production. Using the most active lipase preparation (covalently immobilized L-AK on SwCNTNH2 derivatized with glycerol diglycidyl ether) under optimal conditions, quasi-complete conversion (>99%) of sunflower oil was obtained after only 4 h reaction time. Moreover, the biocatalyst maintained more than 99% of its initial activity in the batch system after multiple recycling experiments.


Assuntos
Biocombustíveis , Enzimas Imobilizadas , Lipase , Nanoconjugados , Pseudomonas fluorescens/metabolismo , Catálise , Humanos , Lipase/química , Solventes
17.
Molecules ; 25(3)2020 Jan 27.
Artigo em Inglês | MEDLINE | ID: mdl-32012738

RESUMO

Functional properties of each enzyme strictly depend on immobilization protocol used for linking enzyme and carrier. Different strategies were applied to prepare the immobilized derivatives of Rhizomucor miehei lipase (RML) and chemically aminated RML (NH2-RML). Both RML and NH2-RML forms were covalently immobilized on glyoxyl sepharose (Gx-RML and Gx-NH2-RML), glyoxyl sepharose dithiothreitol (Gx-DTT-RML and Gx-DTT-NH2-RML), activated sepharose with cyanogen bromide (CNBr-RML and CNBr-NH2-RML) and heterofunctional epoxy support partially modified with iminodiacetic acid (epoxy-IDA-RML and epoxy-IDA-NH2-RML). Immobilization varied from 11% up to 88% yields producing specific activities ranging from 0.5 up to 1.9 UI/mg. Great improvement in thermal stability for Gx-DTT-NH2-RML and epoxy-IDA-NH2-RML derivatives was obtained by retaining 49% and 37% of their initial activities at 70 °C, respectively. The regioselectivity of each derivative was also examined in hydrolysis of fish oil at three different conditions. All the derivatives were selective between cis-5,8,11,14,17-eicosapentaenoic acid (EPA) and cis-4,7,10,13,16,19-docosahexaenoic acid (DHA) in favor of EPA. The highest selectivity (32.9 folds) was observed for epoxy-IDA-NH2-RML derivative in the hydrolysis reaction performed at pH 5 and 4 °C. Recyclability study showed good capability of the immobilized biocatalysts to be used repeatedly, retaining 50-91% of their initial activities after five cycles of the reaction.


Assuntos
Enzimas Imobilizadas/química , Óleos de Peixe/química , Lipase/química , Rhizomucor/enzimologia , Catálise , Estabilidade Enzimática , Concentração de Íons de Hidrogênio , Hidrólise , Solventes/química , Temperatura
18.
Anal Chim Acta ; 1101: 9-22, 2020 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-32029123

RESUMO

With a substantial demand for new anti-obesity drugs for the treatment of obesity, screening lipase inhibitors from natural products has become a popular approach toward drug discovery. Due to the significant advantages of excellent reusability, stability and endurance in extreme pH and temperature conditions, lipase immobilization has been employed as a promising strategy to screen lipase inhibitors. Support is a key factor in the process of enzyme immobilization used to provide excellent biocompatibility, stable physical and chemical properties and abundant binding sites for enzymes. Thus, various supports, including nanofibers, polymeric monoliths, mesoporous materials, nanomaterials, membrane and cellulose paper, are systematically introduced and discussed in this review. Considering these supports, the application of the immobilization of lipase in screening compounds from natural products is also comprehensively reviewed, and the outlook for future research directions is described.


Assuntos
Fármacos Antiobesidade/isolamento & purificação , Inibidores Enzimáticos/isolamento & purificação , Enzimas Imobilizadas/química , Lipase/química , Animais , Fármacos Antiobesidade/química , Biocatálise , Burkholderia cepacia/enzimologia , Avaliação Pré-Clínica de Medicamentos , Inibidores Enzimáticos/química , Enzimas Imobilizadas/antagonistas & inibidores , Fungos/enzimologia , Lipase/antagonistas & inibidores , Estruturas Metalorgânicas/química , Nanoestruturas/química , Plantas/química
19.
Molecules ; 25(3)2020 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-32041136

RESUMO

A series of new hyperbranched aliphatic poly(ß-thioether ester)s were prepared by the enzymatic ring-opening polycondensation of 1,4-oxathiepan-7-one (OTO) and AB2/ABB' comonomer with acid-labile ß-thiopropionate groups. Two kinds of comonomers, methyl 3-((3-hydroxy-2-(hydroxymethyl)propyl)thio)propanoate (HHTP) and methyl 3-((2,3-dihydroxypropyl)thio)propanoate (DHTP), with different primary alcohols and secondary alcohols, were synthesized by thiol-ene click chemistry and thiol-ene Michael addition, respectively. Immobilized lipase B from Candida antarctica (CALB), Novozym 435, was used as the catalyst. The random copolymers were characterized by 1H-NMR, 13C-NMR, GPC, TGA, and DSC. All branched copolyesters had high molecular weights over 15,000 Da with narrow polydispersities in the range of 1.75-2.01 and were amorphous polymers. Their degradation properties under acidic conditions were also studied in vitro. The polymeric nanoparticles of hyperbranched poly(ß-thioether ester)s were successfully obtained and showed good oxidation-responsive properties, indicating their potential for biomedical applications.


Assuntos
Lipase/química , Poliésteres/química , Polímeros/química , Álcoois/química , Materiais Biocompatíveis/química , Candida/enzimologia , Catálise , Enzimas Imobilizadas/química , Proteínas Fúngicas/química , Nanopartículas/química , Oxirredução , Fenantrenos/química
20.
Molecules ; 25(4)2020 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-32093426

RESUMO

The alpha-glucosidase- and lipase-inhibitory activities of three phenalenones (1-3) and one phenylpropanoid (4) from the ethyl acetate extracts of a Pseudolophiosptoma sp. are described. They represent the first secondary metabolites reported from the genus Pseudolophiostoma. Scleroderolide (1) and sclerodione (2) exhibited potent α-glucosidase- and porcine-lipase-inhibitory activity during primary screening, with better IC50 values compared to the positive controls, N-deoxynojirimycin and orlistat. In silico techniques were employed to validate the probable biological targets and elucidate the mechanism of actions of phenalenones 1 and 2. Both compounds exhibited strong binding affinities to both alpha-glucosidase and porcine lipase through H-bonding and π-π interactions. Interestingly, favorable in silico ADME (absorption, distribution, metabolism, and excretion) properties such as gastrointestinal absorption were also predicted using software.


Assuntos
Ascomicetos/química , Inibidores de Glicosídeo Hidrolases , Lipase , Simulação de Acoplamento Molecular , Fenalenos , alfa-Glucosidases/química , Animais , Inibidores de Glicosídeo Hidrolases/química , Inibidores de Glicosídeo Hidrolases/isolamento & purificação , Lipase/antagonistas & inibidores , Lipase/química , Fenalenos/química , Fenalenos/isolamento & purificação , Suínos , Tailândia
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