Showing papers on "Lipase published in 1999"
TL;DR: Three-dimensional structures of bacterial lipases were solved to understand the catalytic mechanism of lipase reactions and will enable researchers to tailor new lipases for biotechnological applications.
Abstract: ▪ Abstract Bacteria produce and secrete lipases, which can catalyze both the hydrolysis and the synthesis of long-chain acylglycerols. These reactions usually proceed with high regioselectivity and enantioselectivity, and, therefore, lipases have become very important stereoselective biocatalysts used in organic chemistry. High-level production of these biocatalysts requires the understanding of the mechanisms underlying gene expression, folding, and secretion. Transcription of lipase genes may be regulated by quorum sensing and two-component systems; secretion can proceed either via the Sec-dependent general secretory pathway or via ABC transporters. In addition, some lipases need folding catalysts such as the lipase-specific foldases and disulfide-bond–forming proteins to achieve a secretion-competent conformation. Three-dimensional structures of bacterial lipases were solved to understand the catalytic mechanism of lipase reactions. Structural characteristics include an α/β hydrolase fold, a catalytic ...
1,072 citations
TL;DR: In this paper, the authors attempted continuous methanolysis of vegetable oil by an enzymatic process, which was conducted by adding methanol stepwise to avoid lipase inactivation.
Abstract: Biodiesel derived from vegetable oils has drawn considerable attention with increasing environmental consciousness. We attempted continuous methanolysis of vegetable oil by an enzymatic process. Immobilized Candida antarctica lipase was found to be the most effective for the methanolysis among lipases tested. The enzyme was inactivated by shaking in a mixture containing more than 1.5 molar equivalents of methanol against the oil. To fully convert the oil to its corresponding methyl esters, at least 3 molar equivalents of methanol are needed. Thus, the reaction was conducted by adding methanol stepwise to avoid lipase inactivation. The first step of the reaction was conducted at 30°C for 10 h in a mixture of oil/methanol (1:1, mol/mol) and 4% immobilized lipase with shaking at 130 oscillations/min. After more than 95% methanol was consumed in ester formation, a second molar equivalent of methanol was added and the reaction continued for 14 h. The third molar equivalent of methanol was finally added and the reaction continued for 24 h (total reaction time, 48 h). This three-step process converted 98.4% of the oil to its corresponding methyl esters. To investigate the stability of the lipase, the three-step methanolysis process was repeated by transferring the immobilized lipase to a fresh substrate mixture. As a result, more than 95% of the ester conversion was maintained even after 50 cycles of the reaction (100 d).
599 citations
TL;DR: The cloning and in vivo functional analysis of a new member of the TG lipase family that is synthesized by endothelial cells in vitro and thus has been termed endothelial lipase (encoded by the LIPG gene) suggests that it may have a role in lipoprotein metabolism and vascular biology.
Abstract: High-density lipoprotein (HDL) cholesterol levels are inversely associated with risk of atherosclerotic cardiovascular disease. At least 50% of the variation in HDL cholesterol levels is genetically determined, but the genes responsible for variation in HDL levels have not been fully elucidated. Lipoprotein lipase (LPL) and hepatic lipase (HL), two members of the triacylglyerol (TG) lipase family, both influence HDL metabolism and the HL (LIPC) locus has been associated with variation in HDL cholesterol levels in humans. We describe here the cloning and in vivo functional analysis of a new member of the TG lipase family. In contrast to other family members, this new lipase is synthesized by endothelial cells in vitro and thus has been termed endothelial lipase (encoded by the LIPG gene). EL is expressed in vivo in organs including liver, lung, kidney and placenta, but not in skeletal muscle. In contrast to LPL and HL, EL has a lid of only 19 residues. EL has substantial phospholipase activity, but less triglyceride lipase activity. Overexpression of EL in mice reduced plasma concentrations of HDL cholesterol and its major protein apolipoprotein A-I. The endothelial expression, enzymatic profile and in vivo effects of EL suggest that it may have a role in lipoprotein metabolism and vascular biology.
510 citations
TL;DR: The X-ray crystal structure of human cPLA2 reveals a flexible lid that must move to allow substrate access to the active site, thus explaining the interfacial activation of this important lipase.
334 citations
TL;DR: Its tissue-restricted pattern of expression and its ability to be expressed by endothelial cells, suggests that endothelial cell-derived lipase may have unique functions in lipoprotein metabolism and in vascular disease.
323 citations
TL;DR: A new enzymatic method of synthesizing methyl ester from plant oil and methanol in a solvent-free reaction system was developed and it is anticipated that such plant oil methyl esters can be used as a biodiesel fuel in the future.
298 citations
TL;DR: A thermophilic microorganism, Bacillus thermoleovorans ID-1, isolated from hot springs in Indonesia, showed extracellular lipase activity and high growth rates on lipid substrates at elevated temperatures.
Abstract: A thermophilic microorganism, Bacillus thermoleovorans ID-1, isolated from hot springs in Indonesia, showed extracellular lipase activity and high growth rates on lipid substrates at elevated temperatures. On olive oil (1.5%, w/v) as the sole carbon source, the isolate ID-1 grew very rapidly at 65°C with its specific growth rate (2.50 h−1) and its lipase activity reached the maximum value of 520 U l−1 during the late exponential phase and then decreased. In addition to this, isolate ID-1 could grow on a variety of lipid substrates such as oils (olive oil, soybean oil and mineral oil), triglycerides (triolein, tributyrin) and emulsifiers (Tween 20, 40). The excreted lipase of ID-1 was purified 223-fold to homogeneity by ammonium sulfate precipitation, DEAE-Sephacel ion-exchange chromatography and Sephacryl S-200 gel filtration chromatography. As a result, the relative molecular mass of the lipase was determined to be 34 kDa on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The enzyme showed optimal activity at 70–75°C and pH 7.5 and exhibited 50% of its original activity after 1 h incubation at 60°C and 30 min at 70°C and its catalytic function was activated in the presence of Ca2+ or Zn2+.
290 citations
TL;DR: Growth and enzyme production in SSF by a Brazilian strain of Penicillium restrictum was studied in this article, where solid waste from the babassu oil industry was used as the basic nutrient source and was supplemented with peptone, olive oil or starch at different C/N ratios.
238 citations
TL;DR: The data suggest that a decreased expression of hormone-sensitive lipase in subcutaneous fat cells, which in turn causes decreased enzyme function and impaired lipolytic capacity of adipocytes, is present in obesity.
212 citations
TL;DR: Candida rugosa lipase was immobilized by covalent binding on controlled poresilica (CPS) using glutaraldehyde ascross-linking agent under aqueous and nonaqueous conditions and revealed good potential for recycling under ahydrous (olive-oil hydrolysis) andNonaqueous (butyl butyrate synthesis) conditions.
Abstract: Candida rugosa lipase was immobilized by covalent binding on controlled pore silica (CPS) using glutaraldehyde as cross-linking agent under aqueous and nonaqueous conditions. The immobilized C. rugosa was more active when the coupling procedure was performed in the presence of a nonpolar solvent, hexane. Similar optima pH (7.5–8.0) was found for both free and immobilized lipase. The optimum temperature for the immobilized lipase was about 10°C higher than that for the free lipase. The thermal stability of the CPS lipase was also greater than the original lipase preparation. Studies on the operational stability of CPS lipase revealed good potential for recycling under aqueous (olive-oil hydrolysis) and nonaqueous (butyl butyrate synthesis) conditions.
209 citations
TL;DR: In this paper, the degradation behavior of poly(e-caprolactone) and poly( dl -lactide) with 0.5 weight fraction of PCL was studied in a phosphate buffer solution containing Pseudomonas (PS) lipase.
TL;DR: An organic solvent-stable lipase (LST-03 lipase) secreted into the culture broth of the Organic solvent-tolerant Pseudomonas aeruginosa L ST-03 was purified by ion-exchange and hydrophobic interaction chromatography in the presence of 2-propanol.
TL;DR: Results suggest that HSL-derived fatty acids are bound by ALBP to facilitate intracellular trafficking of hydrophobic lipids.
Abstract: Hormone-sensitive lipase (HSL) is a cytosolic neutral lipase that functions as the rate-limiting enzyme for the mobilization of free fatty acids in adipose tissue. By using the yeast two-hybrid system to examine the potential interaction of HSL with other cellular proteins, evidence is provided to demonstrate a direct interaction of HSL with adipocyte lipid-binding protein (ALBP), a member of the family of intracellular lipid-binding proteins that binds fatty acids, retinoids, and other hydrophobic ligands. The interaction was demonstrated in vitro by the binding of ALBP to HSL translated in vitro, to HSL in extracts of HSL overexpressing Chinese hamster ovary (CHO) cells, and to HSL in extracts of rat adipose tissue. Finally, the presence of ALBP was documented in immune complexes from rat adipose tissue immunoprecipitated with anti-HSL antibodies. The HSL–ALBP interaction was mapped to an N-terminal 300-aa region of HSL that is distinct from the C-terminal catalytic domain. These results suggest that HSL-derived fatty acids are bound by ALBP to facilitate intracellular trafficking of hydrophobic lipids.
TL;DR: Solid lipid nanoparticles (SLN) show different degradation velocities by the lipolytic enzyme pancreatic lipase as a function of their composition (lipid matrix, stabilizing surfactant).
TL;DR: This review illustrates the biotechnological applications of microemulsions as media for bioorganic reactions, with a principal focus on lipase catalyzed processes.
TL;DR: In this paper, the thermal stability of C. antarctica lipase B (CALB) was studied and compared to adsorbed derivatives from Novo Nordisk at 50°C under wet conditions.
TL;DR: The structure of recombinant human gastric lipase at 3.0-Å resolution is reported, the first structure to be described within the mammalian acid lipase family, and possible explanations for some previously reported mutations leading to the cholesterol ester storage disease are given.
TL;DR: The results indicate that HSL is present in skeletal muscle and is stimulated by adrenaline via beta-adrenergic activation of cAMP-dependent protein kinase, and the enzyme is activated in parallel with glycogen phosphorylase.
Abstract: The enzymic regulation of triacylglycerol breakdown in skeletal muscle is poorly understood. Western blotting of muscle fibres isolated by collagenase treatment or after freeze-drying demonstrated the presence of immunoreactive hormone-sensitive lipase (HSL), with the concentrations in soleus and diaphragm being more than four times the concentrations in extensor digitorum longus and epitrochlearis muscles. Neutral lipase activity determined under conditions optimal for HSL varied directly with immunoreactivity. Expressed relative to triacylglycerol content, neutral lipase activity in soleus muscle was about 10 times that in epididymal adipose tissue. In incubated soleus muscle, both neutral lipase activity against triacylglycerol (but not against a diacylglycerol analogue) and glycogen phosphorylase activity increased in response to adrenaline (epinephrine). The lipase activation was completely inhibited by anti-HSL antibody and by propranolol. The effect of adrenaline could be mimicked by incubation of crude supernatant from control muscle with the catalytic subunit of cAMP-dependent protein kinase, while no effect of the kinase subunit was seen with supernatant from adrenaline-treated muscle. The results indicate that HSL is present in skeletal muscle and is stimulated by adrenaline via beta-adrenergic activation of cAMP-dependent protein kinase. The concentration of HSL is higher in oxidative than in glycolytic muscle, and the enzyme is activated in parallel with glycogen phosphorylase.
TL;DR: An extracellular lipase of Streptomyces rimosus R6-554W was isolated from the culture filtrate by column chromatography and was shown to be a monomeric, basic protein active toward triolein and p-nitrophenyl esters, with preference for those with medium size acyl chain length.
TL;DR: This study shows that the use of two-solvent mixtures may become a feasible alternative for the synthesis of sucrose esters, allowing to exploit the catalytic potential of lipases.
Abstract: The enzymatic synthesis of 6-O-lauroylsucrose and 6-O-palmitoylsucrose was performed by transesterification of sucrose with the corresponding vinyl esters in a medium constituted by two solvents. More specifically, the acylation was carried out in 2-methyl-2-butanol (tert-amyl alcohol) containing a low percentage (not higher than 20%) of dimethyl sulfoxide. Several lipases were able to catalyze the transesterification, but that from Humicola lanuginosa (adsorbed on diatomaceous earth) was particularly useful. We optimized the synthesis of 6-O-lauroylsucrose varying the percentage and nature of the cosolvent, the molar ratio sucrose/vinyl laurate, the nature of bulk solvent and the enzyme content. Under the best conditions (2-methyl-2-butanol/DMSO 4:1 v/v), a sucrose conversion of 70% to 6-O-lauroylsucrose was achieved in 24 h using 50 mg biocatalyst/mL. As a side process, a low percentage (<5% in 24 h) of the initial sucrose is converted into the diesters 6,1'-di-O-lauroylsucrose and 6,6'-di-O-lauroylsucrose. The above methodology was also extended to the synthesis of 6-O-palmitoylsucrose. The acylation process was even faster, giving rise to an 80% conversion to monoester in 48 h using 25 mg biocatalyst/mL. This study shows that the use of two-solvent mixtures may become a feasible alternative for the synthesis of sucrose esters, allowing to exploit the catalytic potential of lipases.
TL;DR: The production of lipase by Yarrowia lipolytica 681 was enhanced significantly (P < 0.05) by olive or corn oil when used as both carbon and inducer sources and the enzyme was highly active towards synthetic triacylglycerols and olive oil.
TL;DR: In vivo, oral administration of corn oil with or without caulerpenyne to rats demonstrated a reduced and delayed peak plasma triacylglycerol concentration with cauler penyne, indicating the possible presence of an inhibitor of pancreatic lipase.
Abstract: The possible presence of an inhibitor of pancreatic lipase (triacylglycerol acylhydrolase, EC 3.1.1.3) was screened in 54 marine algae. An active inhibitor, caulerpenyne, was purified from an extract of Caulerpa taxifolia, using ethyl acetate extraction, followed by successive chromatographies on ODS and silica gel columns. The purified inhibitor was identified by thin-layer chromatography, infrared and nuclear magnetic resonance spectroscopy. Caulerpenyne competitively inhibited lipase activities using emulsified triolein and dispersed 4-methylumbelliferyl oleate (4-MU oleate) as substrates. The concentrations producing 50% inhibition against triolein and 4-MU oleate hydrolysis were 2 mM and 13 μM, respectively. In vivo, oral administration of corn oil with or without caulerpenyne to rats demonstrated a reduced and delayed peak plasma triacylglycerol concentration with caulerpenyne.
TL;DR: All ascorbic acid fatty esters produced by this procedure exhibited a significant antioxidant activity in a micellar substrate composed of linoleic acid.
Abstract: The esterification of some natural antioxidants such as cinnamic acid derivatives and ascorbic acid in non-aqueous media, catalyzed by immobilized lipases from Candida antarctica and Rhizomucor miehei, was investigated. The alcohol chain length affected the rate of esterification of cinnamic acids by both lipases. Higher reaction rates were observed when the esterification was carried out with medium- or long-chain alcohols. The rate also depended on aromatic acid structure. The reactivity of the carboxylic function of the cinnamic acids was affected by electron-donating substituents in the aromatic ring. Higher yields were observed for the esterification of p-hydroxyphenylacetic acid (97%) catalyzed by C. antarctica lipase and for the esterification of cinnamic acid (59%) catalyzed by R. miehei lipase. Candida antarctica lipase was more suitable for producing ascorbic acid fatty esters, catalyzing with a relatively high yield (up to 65% within 24 h) the regioselective esterification of ascorbic acid with various fatty acids in 2-methyl-2-propanol. The reaction rate and yield depended on the fatty acid chain length and on the molar ratio of reactants. All ascorbic acid fatty esters produced by this procedure exhibited a significant antioxidant activity in a micellar substrate composed of linoleic acid.
TL;DR: The granular immobilized lipase derived from Candida antartica showed extremely efficient catalysis in the polymerization of epsilon-caprolactone and the enzymatic polymerizability of lactones was quantitatively evaluated by Michaelis-Menten kinetics.
TL;DR: It has been suggested that enzymatically inactive HL can play a role in hepatic lipoprotein uptake forming a 'bridge' by binding to the lipop protein and to the cell surface, and the interesting possibility that production and secretion of mutant inactive HL could promote clearance of VLDL remnants is raised.
TL;DR: In this article, an enzyme-catalyzed ring-opening polymerization of a novel carbonate monomer, 5-methyl-5-benzyloxycarbonyl-1,3-dioxan-2-one, was reported.
Abstract: Water-soluble polycarbonate having pendent carboxyl groups on the main-chain carbons is reported for the first time. This paper describes synthesis and enzyme-catalyzed ring-opening polymerization of a novel carbonate monomer, 5-methyl-5-benzyloxycarbonyl-1,3-dioxan-2-one (1). Various commercially available lipases were screened for their ability to polymerize 1 in bulk at 80 °C. Monomer conversion and molecular weight of the polymer were significantly influenced by the source of the enzyme. For example, of the seven lipases screened, lipase AK (from Pseudomonas fluorescens) gave the highest monomer conversion (97%) and molecular weight (Mn = 6100). In reactions carried out under identical experimental conditions, no polymerization was observed when thermally deactivated lipase AK was used. Debenzylation of 2 by catalytic hydrogenation led to the corresponding linear polycarbonate, 3, with pendent carboxyl groups. Presence of pendent carboxyl groups is expected to enhance the biodegradability of the polyc...
TL;DR: In this paper, soil lipase activity and counts of oil-degrading microorganisms were measured at regular time intervals, and correlations with the levels of hydrocarbon concentrations in soil were investigated.
Abstract: The evaluation of soil lipase activity as a tool to monitor the decontamination of a freshly oil-polluted soil was tested in a laboratory study. An arable soil was experimentally contaminated with diesel oil at 5 mg hydrocarbons g−1 soil dry weight and incubated with and without fertilization (N-P-K) for 116 days at 20 °C. Lipase activity and counts of oil-degrading microorganisms were measured at regular time intervals, and the correlations with the levels of hydrocarbon concentrations in soil were investigated. The residual soil hydrocarbon concentration correlated significantly negatively with soil lipase activity and with the number of oil-degrading microorganisms, independent of fertilization. The induction of soil lipase activity is a valuable indicator of oil biodegradation in naturally attenuated (unfertilized) and bioremediated (fertilized) soils.
TL;DR: Overall, the data indicate that in the mouse, other enzymes besides CEL participate in the hydrolysis of dietary cholesteryl esters, retinyl ester, and triglycerides.
Abstract: Carboxyl ester lipase (CEL; EC 3.1.1.13) hydrolyzes cholesteryl esters and retinyl esters in vitro. In vivo, pancreatic CEL is thought to liberate cholesterol and retinol from their esters prior to absorption in the intestine. CEL is also a major lipase in the breast milk of many mammals, including humans and mice, and is thought to participate in the processing of triglycerides to provide energy for growth and development while the pancreas of the neonate matures. Other suggested roles for CEL include the direct facilitation of the intestinal absorption of free cholesterol and the modification of plasma lipoproteins. Mice with different CEL genotypes [wild type (WT), knockout (CELKO), heterozygote] were generated to study the functions of CEL in a physiological system. Mice grew and developed normally, independent of the CEL genotype of the pup or nursing mother. Consistent with this was the normal absorption of triglyceride in CELKO mice. The absorption of free cholesterol was also not significantly dif...
TL;DR: Synthesis of 6-O-acylate-α-d-glycopyranose from underivatised substrates in anhydrous tert-butanol was achieved using immobilised lipases from Candida antarctica and Mucor miehei using maltose as substrate while with maltotriose no reaction was observed.
Abstract: Synthesis of 6-O-acylate-α-d-glycopyranose from underivatised substrates in anhydrous tert-butanol was achieved using immobilised lipases from Candida antarctica and Mucor miehei. Except for acetic acid, the initial reaction rates with the C. antarctica lipase were independent of acyl donor chain lengths and in a range of 3.9±0.4 μmol glucose converted min−1 g enzyme preparation. The catalytic activity of the M. miehei lipase increased with increasing acyl donor chain length with a maximum for stearic acid of 0.45 μmol min−1 g. Using maltose as substrate, the catalytic activity decreased by a factor of 48 and 20 with the lipase from C. antarctica and M. miehei, respectively, while with maltotriose no reaction was observed.
TL;DR: Two new esterases (JEA and JEB) and a lipase (JL) were extracted from the seeds of Jatropha curas L and JL is a potentially useful biocatalyst in the hydrolysis of triglycerides in organic solvents.