Showing papers on "Lipase published in 2006"
TL;DR: Together, ATGL and HSL are responsible for more than 95% of the TG hydrolase activity present in murine WAT, suggesting that ATGL is the sole target for CGI-58-mediated activation of adipose lipolysis.
617 citations
TL;DR: Light is shed on the mechanism of lipolysis in plants and it is established that a central component is evolutionarily conserved among eukaryotes.
Abstract: Triacylglycerol hydrolysis (lipolysis) plays a pivotal role in the life cycle of many plants by providing the carbon skeletons and energy that drive postgerminative growth. Despite the physiological importance of this process, the molecular mechanism is unknown. Here, a genetic screen has been used to identify Arabidopsis thaliana mutants that exhibit a postgerminative growth arrest phenotype, which can be rescued by providing sugar. Seventeen sugar-dependent (sdp) mutants were isolated, and six represent new loci. Triacylglycerol hydrolase assays showed that sdp1, sdp2, and sdp3 seedlings are deficient specifically in the lipase activity that is associated with purified oil bodies. Map-based cloning of SDP1 revealed that it encodes a protein with a patatin-like acyl-hydrolase domain. SDP1 shares this domain with yeast triacylglycerol lipase 3 and human adipose triglyceride lipase. In vitro assays confirmed that recombinant SDP1 hydrolyzes triacylglycerols and diacylglycerols but not monoacylglycerols, phospholipids, galactolipids, or cholesterol esters. SDP1 is expressed predominantly in developing seeds, and a SDP1–green fluorescent protein fusion was shown to associate with the oil body surface in vivo. These data shed light on the mechanism of lipolysis in plants and establish that a central component is evolutionarily conserved among eukaryotes.
388 citations
TL;DR: It is demonstrated here that the N-terminal coiled-coil domain of Angptl-4 binds transiently to LPL and that the interaction results in conversion of the enzyme from catalytically active dimers to inactive, but still folded, monomers with decreased affinity for heparin.
Abstract: Lipoprotein lipase (LPL) has a central role in lipoprotein metabolism to maintain normal lipoprotein levels in blood and, through tissue specific regulation of its activity, to determine when and in what tissues triglycerides are unloaded. Recent data indicate that angiopoietin-like protein (Angptl)-4 inhibits LPL and retards lipoprotein catabolism. We demonstrate here that the N-terminal coiled-coil domain of Angptl-4 binds transiently to LPL and that the interaction results in conversion of the enzyme from catalytically active dimers to inactive, but still folded, monomers with decreased affinity for heparin. Inactivation occurred with less than equimolar ratios of Angptl-4 to LPL, was strongly temperature-dependent, and did not consume the Angptl-4. Furthermore, we show that Angptl-4 mRNA in rat adipose tissue turns over rapidly and that changes in the Angptl-4 mRNA abundance are inversely correlated to LPL activity, both during the fed-to-fasted and fasted-to-fed transitions. We conclude that Angptl-4 is a fasting-induced controller of LPL in adipose tissue, acting extracellularly on the native conformation in an unusual fashion, like an unfolding molecular chaperone.
385 citations
TL;DR: There was no obvious loss in lipase activity even after being repeatedly used for 200 cycles with tert-butanol as the reaction medium, and it has been found that lipase also showed good stability in this novel system.
Abstract: tert-Butanol, as a novel reaction medium, has been adopted for lipase-catalyzed transesterification of rapeseed oil for biodiesel production, with which both the negative effects caused by excessive methanol and by-product glycerol could be eliminated. Combined use of Lipozyme TL IM and Novozym 435 was proposed further to catalyze the methanolysis and the highest biodiesel yield of 95% could be achieved under the optimum conditions (tert-butanol/oil volume ratio 1:1; methanol/oil molar ratio 4:1; 3% Lipozyme TL IM and 1% Novozym 435 based on the oil weight; temperature 35 °C; 130 rpm, 12 h). There was no obvious loss in lipase activity even after being repeatedly used for 200 cycles with tert-butanol as the reaction medium. Furthermore, waste oil was also explored for biodiesel production and it has been found that lipase also showed good stability in this novel system.
348 citations
TL;DR: Candida antarctica lipase B (CAL-B) is an ideal tool for the synthesis and resolution of a wide range of nitrogenated compounds that can be used for the production of pharmaceuticals and interesting manufactures in the industrial sector.
Abstract: Candida antarctica lipase B (CAL-B) is a very effective catalyst for the production of amines and amides using different enzymatic procedures. Simplicity of use, low cost, commercial availability and recycling possibility make this lipase an ideal tool for the synthesis and resolution of a wide range of nitrogenated compounds that can be used for the production of pharmaceuticals and interesting manufactures in the industrial sector.
337 citations
TL;DR: A better understanding of the relative contribution of the two types of receptors and evidence for the in vivo involvement of alpha2-adrenoceptors in the physiological control of subcutaneous adipose tissue lipolysis are provided.
329 citations
TL;DR: In this paper, a lipase from Candida sp, suitable for transesterification of fats and oils to produce fatty acid methyl ester (FAME), was immobilized on a cheap cotton membrane, and the conversion ratio of salad oil to biodiesel could reach up to 96% with the optimal reaction conditions.
Abstract: A lipase from Candida sp., suitable for transesterification of fats and oils to produce fatty acid methyl ester (FAME), was immobilized on a cheap cotton membrane, in this paper. The conversion ratio of salad oil to biodiesel could reach up to 96% with the optimal reaction conditions. Continuous reaction in a fixed bed reactor was also investigated. A three-step transesterification with methanol (methanolysis) of oil was conducted by using a series of nine columns packed with immobilized Candida sp. 99–125 lipase. As substrate of the first reaction step, plant or waste oil was used together with 1/3 molar equivalent of methanol against total fatty acids in the oil. Mixtures of the first- and second-step eluates and 1/3 molar equivalent of methanol were used for the second- and third-reaction steps. A hydrocyclone was used in order to on-line separate the by-product glycerol after every 1/3 molar equivalent of methanol was added. Petroleum ether was used as solvent (3/2, v/v of oil) and the pump was operated with a flow rate of 15 L/h giving an annual throughput of 100 t. The final conversion ratio of the FAME from plant oil and waste oil under the optimal condition was 90% and 92%, respectively. The life of the immobilized lipase was more than 10 days. This new technique has many strongpoints such as low pollution, environmentally friendly, and low energy costs.
318 citations
TL;DR: Yeast Tgl4 is identified as a functional ortholog of mammalian adipose triglyceride lipase, and Serine 315 in the GXSXG lipase active site consensus sequence of the patatin domain of Tgl3 is essential for catalytic activity.
294 citations
TL;DR: It is demonstrated that hypoxic cultures of M. tuberculosis, which had accumulated TG, hydrolyzed the stored TG when subjected to nutrient starvation, and in the lipY-deficient mutant, TG utilization was drastically decreased under nutrient-deprived condition.
259 citations
TL;DR: A simple and versatile method for the preparation of functional enzyme-gold nanoparticle conjugates using "click" chemistry has been developed.
243 citations
TL;DR: The biochemical basis of spontaneous lipolysis is still poorly understood, but it appears to be related to a balance between activating and inhibiting factors in the milk as mentioned in this paper, which is a constant concern in the dairy industry.
TL;DR: In this paper, an electrostatic layer-by-layer deposition technique was used to prepare corn oil-in-water emulsions that contained droplets coated by lecithin, chitosan, or bile extract.
Abstract: The objective of this study was to investigate the influence of interfacial composition and electrical charge on the in vitro digestion of emulsified fats by pancreatic lipase. An electrostatic layer-by-layer deposition technique was used to prepare corn oil-in-water emulsions (3 wt% oil) that contained droplets coated by (1) lecithin, (2) lecithin–chitosan, or (3) lecithin–chitosan–pectin. Pancreatic lipase (1.6 mg mL−1) and/or bile extract (5.0 mg mL−1) were added to each emulsion, and the particle charge, droplet aggregation, and free fatty acids released were measured. In the presence of bile extract, the amount of fatty acids released per unit amount of emulsion was much lower in the emulsions containing droplets coated by lecithin–chitosan (38 ± 16 μmol mL−1) than those containing droplets coated by lecithin (250 ± 70 μmol mL−1) or lecithin–chitosan–pectin (274 ± 80 μmol mL−1). In addition, there was much more extensive droplet aggregation in the lecithin–chitosan emulsion than in the other two emulsions. We postulated that lipase activity was reduced in the lecithin–chitosan emulsion as a result of the formation of a relatively thick cationic layer around each droplet, as well as the formation of large flocs, which restricted the access of the pancreatic lipase to the lipids within the droplets. Our results also suggest that droplets initially coated by a lecithin–chitosan–pectin layer did not inhibit lipase activity, which may have been because the chitosan–pectin desorbed from the droplet surfaces thereby allowing the enzyme to reach the lipids; however, further work is needed to establish this. This information could be used to create food emulsions with low caloric level, or to optimize diets for individuals with lipid digestion problems.
TL;DR: Scanning electron microscopy analysis showed that CLEAs prepared in the presence of BSA were less amorphous and closer in morphology to CLEAs of other enzymes described in the literature.
TL;DR: This review is aimed at compiling the information on properties of various yeast lipases and genes encoding them.
TL;DR: In the present paper the recent developments published in the CRL field are overviewed, focusing on comparison of structural and biochemical data among isoenzymes (Lip1-Lip5), and their influence in the biocatalytical performance.
TL;DR: This work is presenting the effect of different drying conditions, typical in the processing of dry-cured meat products, on the activity of muscle proteases and lipases as well as its relevance for the final product quality.
Abstract: Several muscle proteases (cathepsins, calpains, peptidases and aminopeptidases) and lipases (lysosomal acid lipase, acid phospholipase and adipose tissue lipase) are involved in important biochemical mechanisms taking place during the processing of dry-cured meat products which are directly related to the final quality. These enzymes are affected by the conditions typically found in the processing of dry-cured meat products, being dehydration one of the most important factors. This work is presenting the effect of different drying conditions, typical in the processing of dry-cured meat products, on the activity of muscle proteases and lipases as well as its relevance for the final product quality.
TL;DR: Results indicate that the pH and thermal stabilities of lipases increase upon immobilization, and there is an increase of the V(max) value for the immobilized lipases on the chitosan- and gelatin-modified nanofibrous membranes.
TL;DR: Enzymatic preparations of highly enantiopure β-amino acids have been reviewed and new approaches to improve the quality and consistency of these preparations are proposed.
TL;DR: The minimal adipose phenotype of hormone-sensitive lipase (HSL)-null mice suggested that other hormonally responsive lipase(s) were present in adipocytes.
Abstract: The minimal adipose phenotype of hormone-sensitive lipase (HSL)-null mice suggested that other hormonally responsive lipase(s) were present in adipocytes. Recent studies have characterized a new ad...
TL;DR: In this article, a response surface approach has been used to study the production of an extracellular lipase from Aspergillus carneus, which has the property of immense industrial importance.
Abstract: A response surface approach has been used to study the production of an extracellular lipase from Aspergillus carneus, which has the property of immense industrial importance. Interactions were studied for five different variables (sunflower oil, glucose, peptone, agitation rate and incubation period), which were found influential for lipase production by one-at a time method. We report a 1.8-fold increase in production, with the final yield of 12.7 IU/ml in comparison to 7.2 U/ml obtained by one-at-a-time method. Using the statistical approach (response surface methodology (RSM)) the optimum values of these most influential parameters were as follows: sunflower oil (1%), glucose (0.8%), peptone (0.8%), agitation rate (200 rpm) and incubation period (96 h) at 37 °C. The subsequent verification experiment confirmed the validity of the model.
TL;DR: The immobilization procedure developed provides a promising solution for application of lipase in aqueous and microaqueous reaction system and provides an appreciable stabilization of the biocatalyst, changing its thermal deactivation profile.
TL;DR: In this paper, the authors used the enzyme Candida antarctica (Novozyme 435) immobilized on acrylic resin as an unconventional catalyst for in situ epoxidation of soybean oil.
Abstract: The lipase Candida antarctica (Novozyme 435) immobilized on acrylic resin was used as an unconventional catalyst for in situ epoxidation of soybean oil. The reactions were carried out in toluene. The peracid used for converting TG double bonds to oxirane groups was formed by reaction of FFA and hydrogen peroxide. The reaction conditions were optimized by varying the lipase concentration, solvent concentration, molar ratio of hydrogen peroxide to double bond, oleic acid concentration, and reaction temperature. The kinetic study showed that 100% conversion of double bonds to epoxides can be obtained after 4 h. The addition of free acids was not required for the reaction to proceed to conversions exceeding 80%, presumably owing to generation of FFA by hydrolysis of soybean oil. The enzyme catalyst was found to deteriorate after repeated runs.
TL;DR: In this article, the lipase-catalyzed alcoholysis of soybean oil deodorizer distillate (SODD) for biodiesel production was studied during this system both free fatty acids and glycerides could be converted to biodiesel simultaneously tert-Butanol has been adopted as the reaction medium, in which both the negative effects caused by excessive methanol and byproduct glycerol could be eliminated completely.
Abstract: Lipase-catalyzed alcoholysis of soybean oil deodorizer distillate (SODD) for biodiesel production was studied During this system both free fatty acids and glycerides could be converted to biodiesel simultaneously tert-Butanol has been adopted as the reaction medium, in which both the negative effects caused by excessive methanol and by-product glycerol could be eliminated completely There was no obvious loss in lipase activity even after being repeatedly used for 120 cycles Fine-pored silica gel and 3 A molecular were found to be effective to control by-product water concentration and much higher biodiesel yield could be achieved with those adsorbents present in the reaction system The highest biodiesel yield of 97% could be achieved with 3 A molecular sieve as the adsorbent
TL;DR: Several data obtained with gastric lipase, classical pancreaticlipase, pancreatic lipase-related protein 2 and phosphatidylserine-specific phospholipase A1 were chosen here to illustrate these specific features of interfacial enzymology.
TL;DR: C. cylindracea NRRL Y-17506 showed the highest lipase activity on all the typologies of OMW used, and was markedly affected by the type of nitrogen source and was induced by the addition of olive oil.
TL;DR: This article reviews the main work done on the influence of the type, origin and concentration of the enzyme, the nature of the reaction, the operating conditions, the composition of the reactional media and thenature of substrates on regioselectivity, initial rates and conversions yields of the acylation.
TL;DR: Differences between the kinetic properties suggest that when they were tested, one or both fungal lipases might still have been associated with non-proteic compounds originating from the culture medium.
TL;DR: It was found that cell immobilization within reticulated polyurethane foam biomass support particles strongly inhibits the secretion of membrane-bound lipase into the culture medium, which suggests that ROL31 localized in the membrane plays a crucial role in the methanolysis activity of R. oryzae cells.
Journal Article•
TL;DR: Lipase production in Aspergillus niger J-1 was tested using both submerged fermentation (SmF) and solid-state fermentation (SSF) on a mineral culture medium and wheat bran, respectively and the optimization of the culture medium was carried out for both SmF and SSF.
Abstract: Summary Lipase production in Aspergillus niger J-1 was tested using both submerged fermentation (SmF) and solid-state fermentation (SSF) on a mineral culture medium and wheat bran, respectively. The optimization of the culture medium was carried out for both SmF and SSF. The maximum lipase activity, 1.46 IU/mL, was obtained during the submerged fermentation in a medium containing glucose at 2 % and olive oil at 2 % under conditions of 1 vvm and 450 m –1 . However, 9.14 IU/g of dry solid substrate equivalent to 4.8 IU/mL of lipase activity was reached using solid-state fermentation process with a medium containing 0.75 % of ammonium sulphate and 0.34 % of urea. The optimum pH and temperature for enzymatic activity were pH=6 and 40 °C, respectively. The enzyme also exhibited 80 % of its initial activity in neutral and mildly acid media and at temperatures between 20 and 30 °C for a period of 24 hours.
TL;DR: Its marked stability and activity in organic solvents suggest that this lipase is highly suitable as a biotechnological tool in a water-restricted medium with a variety of applications including organosynthetic reactions and the control and prevention of MWF putrification in the metal industry.