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1.
《Process Biochemistry》2007,42(3):384-391
An extracellular lipase from Yarrowia lipolytica (YlLip2) has been purified by ion exchange chromatography on Q sepharose FF, followed by hydrophobic interaction chromatography on butyl sepharose FF. SDS-PAGE showed that the molecular weight of this lipase is about 38 kDa. N-terminal amino acid sequencing and MALDI-TOF mass spectral analysis showed that this lipase is encoded by gene LIP2 (GenBank accession no. AJ012632). Enzymatic deglycosylation showed that this lipase is a glycosylated protein which contains about 12% sugar. The corresponding deglycosylated lipase remained 88% specific activity of untreated lipase. There was a high amino acid sequence identity (91%) between YlLip2 and Candida deformans lipase CdLip1 (GenBank accession no. AJ428393). The optima temperature and pH for the purified lipase was 40 °C and 8.0, respectively. The lipase showed a preference for long chain fatty acid methyl esters (C12–C16), with the highest activity toward methyl myristate (C14). Lipase activity was stimulated by Ca2+ and Mg2+ and inhibited by Zn2+, Ni2+ and Cu2+, whereas EDTA had no effect on its activity. A 0.1% of Tween 80 and Span 65 increased slightly the enzyme activity and SDS inhibited it.  相似文献   

2.
The activities of microbial lipases were inhibited by bile salts in a non-emulsifying assay system. To protect lipase activities from inactivation, the effects of proteins and amino acids were investigated. Bovine serum albumin (BSA) and α-lactalbumin (α-LA) stored the bile salts inhibited microbial lipases. Among N-end amino groups contained in BSA, L-histidine restored the activities of the bile salts inhibited microbial lipases. On the other hand, pancreatic lipase activity was stimulated by not only BSA, but L-histidine and L-aspartic acid as N-end amino groups of BSA and additionally accelerated it in combination with bile salts.  相似文献   

3.
The changes in the structure and catalytic properties of fungal lipases (Candida rugosa, Rhizomucor miehei, Mucor javanicus) were investigated in micellar solutions of bile salts that differ in their hydrophilic–lypophilic balance and reaction medium properties. The methods of circular dichroism and tryptophan fluorescence were applied to estimate the changes in peptide structure within complexes with bile-salt micelles. Bile salts do not exert a significant influence on the structure of the enzymes under study: in the Rh. miehei and M. javanicus lipases the α-helix content was slightly decreased; an influence of the bile salts on the C. rugosa structure was not revealed. Despite negligible structural modifications in the enzymes, a considerable change in their catalytic properties, namely an abrupt decrease in catalytic effectiveness was observed in bile-salt solutions. Substrate–bile salt micelle complex formation was demonstrated by the NMR self-diffusion method. A model of the regulation of fungal lipase activity was proposed.  相似文献   

4.

Background

Lipases differ from one another with respect to certain properties, and such differences can be very important for various industrial applications. Considering the rapidly developing nature of the relevant industries, there is a need for new lipases with characteristics differing from those of existing enzymes.

Methods

In this study, a bacterium was isolated from both the surface mucus layer and gills of rainbow trout (Oncorhynchus mykiss) from Giresun, Turkey. The bacterial species was identified based on its morphological and physiochemical properties, and on its 16S rDNA sequence. The qualitative activity of the bacterial lipase was determined on Rhodamine B and Tween-20 agar plates. The lipase was partially purified from the supernatant of bacterial cultures, and then characterized.

Results

The bacterial strain was identified as Acinetobacter sp. strain SU15. The enzyme from Asp-SU15 exhibits maximum activity toward p-nitrophenyl dodecanoate (C12) at 40°C and pH 8.0. The specific activity of the lipase was calculated to be 10.059 U·L–1. The molecular mass of the enzyme was determined to be ~62 kDa via SDS-PAGE. However, native-PAGE indicated that the enzyme forms very large active aggregates, with molecular masses exceeding 250 kDa. The catalytic activity of the enzyme is enhanced in the presence of Co2+, Ca2+, and methanol, but is partially inhibited by Ni2+, ethyl acetate, and butanol.

Conclusions

Further research could examine possible industrial applications for the lipase from Asp-SU15.
  相似文献   

5.
Summary Lipase fromC. cylindracea was covalently immobilised to a number of surface-treated ceramic supports (3–10 mg. (g dry wt support)–1). At room temperature, the immobilised lipase could convert R,S-citronellol and butyric acid to citronellyl butyrate at rates in the range 7–51 mol. (mg lipase.min)–1. The lipase maintained 90–100% of its initial activity over a period of 150 days.  相似文献   

6.
The kinetic parameters of lipase, bacterial secondaryproduction (BSP) and bacterial numbers (BN) were determined fortnightlyduringthe development of the summer phytoplankton bloom at twostationsof Alte Donau, a hypertrophic stagnant dead arm of the riverDanubein Vienna. Until the middle of August we observed a gradualincrease in lipase activity as well as BN and BSP rates tothe maximum of 19.9 nmol l–1 h–1,4.5×109cells l–1 and 8.1 g C l–1 h–1,respectively. Atthe end of August and during September we found a markeddecreasein all bacterial parameters, coinciding with a progressingincreaseof chlorophyll a concentrations at both sampling sites. Themaximalvalues of lipase Vmax were determined in the bottom waterlayer (avg. 13.7±6.5 nmol l–1 h–1) probablyowingto the predominating importance of polymeric matter in thesubstrate pool for microheterotrophs in this water zone.Differential filtration experiments showed that 20.1% to56.3% ofthe total lipase activity and 4.2% to 9.0% of the totalbacterialnumbers in Alte Donau water samples occurred in 0.2-mfiltrate. Further experiments indicated that the highcontributionto lipase activity in the 0.2-m filtrate was rather dueto thepresence of 0.2 m filterable bacteria than to solubleenzymemolecules. Moreover, we observed higher bacterial lipaseactivityin 0.2 m filtrate than in unfiltered samples. Thepossibleinfluence of limiting factors on the metabolism of insitubacteria is discussed.  相似文献   

7.
The conformation of a surface loop, the lid, controls activity of pancreatic triglyceride lipase (PTL) by moving from a position that sterically hinders substrate access to the active site into a new conformation that opens and configures the active site. Movement of the lid is accompanied by a large change in steady state tryptophan fluorescence. Although a change in the microenvironment of Trp-253, a lid residue, could account for the increased fluorescence, the mechanism and tryptophan residues have not been identified. To identify the tryptophan residues responsible for the increased fluorescence and to gain insight into the mechanism of lid opening and the structure of PTL in aqueous solution, we examined the effects of mutating individual tryptophan residues to tyrosine, alanine, or phenylalanine on lipase activity and steady state fluorescence. Substitution of tryptophans 86, 107, 253, and 403 reduced activity against tributyrin with the largest effects caused by substituting Trp-86 and Trp-107. Trp-107 and Trp-253 fluorescence accounts for the increased fluorescence emissions of PTL that is stimulated by tetrahydrolipstatin and sodium taurodeoxycholate. The largest contribution is from Trp-107. Contrary to the prediction from the crystal structure of PTL, Trp-107 is likely exposed to solvent. Both tetrahydrolipstatin and sodium taurodeoxycholate are required to produce the increased fluorescence in PTL. Alone, neither is sufficient. Colipase does not significantly influence the conformational changes leading to increased emission fluorescence. Thus, Trp-107 and Trp-253 contribute to the change in steady state fluorescence that is triggered by mixed micelles of inhibitor and bile salt. Furthermore, the results suggest that the conformation of PTL in solution differs significantly from the conformation in crystals.Lipases belong to a large gene family of proteins characterized by a common protein structure (1, 2). Included in this family are pancreatic triglyceride lipase (PTL,2 triacylglycerol acylhydrolase, EC 3.1.1.3) and its close homologues pancreatic triglyceride lipase related proteins 1 and 2 (3). Not only do these pancreatic lipases have highly conserved primary structures, their x-ray crystal structures are essentially identical (46). Each contains two domains, a globular N-terminal domain consisting of an α/β hydrolase fold and a C-terminal domain consisting of a β-sandwich structure. A striking feature of these lipases and many others is the presence of a surface loop termed the lid domain. Together with the β5 loop and β9 loops of the N-terminal domain, the lid domain sterically hinders access of substrate to the active site. In this conformation, PTL cannot hydrolyze substrate, and the existence of another conformation was proposed (6).Subsequently, a second, open conformation of PTL was identified in studies of the crystal structure of the PTL-colipase complex (7, 8). In these studies, the investigators obtained crystals of the complex in the presence and absence of detergent and phospholipid mixed micelles. Without micelles, the lid domain remained in the same closed position as observed in the PTL structure even though colipase clearly bound to the C-terminal domain (8). With micelles, the lid domain and the β5 loop adopted new conformations (7). A large hinge movement of the lid moved the domain away from the active site to form new interactions with colipase. The lid movement opened and configured the active site to generate a conformation compatible with catalysis. Additionally, the movement exposed a large hydrophobic surface on the PTL-colipase complex, a surface that likely contributes to the anchoring of the complex on the substrate interface.Although x-ray crystallography studies clearly demonstrated two conformations of PTL and other lipases, these only provide a static picture of what may be the beginning and end of the process. The mechanism that triggers lid opening and the presence of intermediate conformations remains speculative. Initially, many assumed that a lipid-water interface triggered the conformational change (9). However, a number of studies using inhibitors, small angle neutron scattering, neutron diffraction, and monoclonal antibodies suggest that the lid can open in solution (1014). In these studies, it was variously suggested that bile salt micelles and colipase or bile salt micelles alone were sufficient to trigger lid opening. The presence of a lipid substrate was not required.None of these studies addressed the relative contribution of bile salts and colipase to the lid opening. A recent paper described the use of electron paramagnetic resonance spectroscopy combined with site-directed spin labeling to monitor conformational changes in the PTL lid and to determine the effect of bile salts and colipase on lid opening (15). A cysteine was substituted for Asp-250 in the lid domain, and a paramagnetic probe was linked at that site. Using this method, the authors observed a mixture of closed and open conformations of the lid in the presence of bile salt micelles alone. Colipase by itself did not induce lid opening, but in the presence of bile salt micelles, colipase increased the relative concentration of PTL in the open conformation. Although the spin labeling did not have dramatic effects on the activity of the labeled PTL, it may not be benign. The presence of the probe may alter the kinetics of lid opening and may explain why a portion of PTL always stayed in the closed position.Another spectral method to follow conformation changes in proteins is fluorescence spectroscopy of native tryptophan. After systematically mutating the three tryptophans to alanine, investigators measured the binding of Thermomyces lanuginosus lipase and the mutants to mixed micelles of cis-parinaric acid and bile salt by fluorescence quenching and fluorescence resonance energy transfer (16). The measured values correlated with lid opening and depended on the presence of the single tryptophan in the lid. PTL shows a large increase in tryptophan fluorescence when incubated with a lipase inhibitor, tetrahydrolipstatin (THL), in the presence of bile salts (11). It was suggested, but not demonstrated, that the fluorescence change reflected movement of the lid domain. Because PTL contains seven tryptophan residues including one in the lid, Trp-253, the interpretation of this study is quite complicated. Another study monitoring time-resolved fluorescence of PTL and several tryptophan mutants demonstrated that Trp-30 makes a significant contribution to the tryptophan fluorescence of PTL (17). The lid tryptophan, Trp-253, had a low quantum yield and contributed considerably less to the overall tryptophan fluorescence. This report did not include investigations of PTL fluorescence in the presence of bile salts or colipase. Consequently, the assumption that the large increase in steady state fluorescence of PTL in the presence of THL and bile salt results from changes in the environment of the lid domain tryptophan remains unproven.To determine whether the increased tryptophan fluorescence of PTL in THL and bile saIt represents a conformational change in PTL, we measured the effect of tryptophan substitution mutations on the activity and intrinsic steady state fluorescence of PTL. Each of the seven tryptophans was mutated to tyrosine. Selected tryptophans were mutated to alanine or phenylalanine. Each mutant PTL was expressed and purified. We monitored the effect of bile salts, colipase, THL, and mixtures of these compounds on the steady state fluorescence of PTL.  相似文献   

8.
Among 97 fungal strains isolated from soil collected in the arctic tundra (Spitsbergen), Penicillium chrysogenum 9 was found to be the best lipase producer. The maximum lipase activity was 68 units mL–1 culture medium on the fifth day of incubation at pH 6.0 and 20°C. Therefore, P. chrysogenum 9 was classified as a psychrotrophic microorganism. The non-specific extracellular lipase showed a maximum activity at 30°C and pH 5.0 for natural oils or at pH 7.0 for synthetic substrates. Tributyrin was found to be the best substrate for lipase, among those tested. The Km and Vmax were calculated to be 2.33 mM and 22.1 units mL–1, respectively, with tributyrin as substrate. The enzyme was inhibited more by EDTA than by phenylmethylsulfonyl fluoride and was reactivated by Ca2+. The P. chrysogenum 9 lipase was very stable in the presence of hexane and 1,4-dioxane at a concentration of 50%, whereas it was unstable in presence of xylene.  相似文献   

9.

Objectives

To identify novel cold-active lipases from fungal sources and improve their production by heterologous expression in Pichia pastoris.

Results

A novel cold-active lipase gene (ReLipB) from Rhizomucor endophyticus was cloned. ReLipB was expressed at a high level in Pichia pastoris using high cell-density fermentation in a 5-l fermentor with the highest lipase activity of 1395 U/ml. The recombinant lipase (RelipB) was purified and biochemically characterized. ReLipB was most active at pH 7.5 and 25 °C. It was stable from pH 4.5–9.0. It exhibited broad substrate specificity towards p-nitrophenyl (pNP) esters (C2–C16) and triacylglycerols (C2–C12), showing the highest specific activities towards pNP laurate (231 U/mg) and tricaprylin (1840 U/mg), respectively. In addition, the enzyme displayed excellent stability with high concentrations of organic solvents including cyclohexane, n-hexane, n-heptane, isooctane and petroleum ester and surfactants.

Conclusions

A novel cold-active lipase from Rhizomucor endophyticus was identified, expressed at a high level and biochemically characterized. The high yield and unique enzymatic properties make this lipase of some potential for industrial applications.
  相似文献   

10.

Objectives

To investigate the lipase-catalyzed acylation of quercetin with oleic acid using Candida antarctica lipase B.

Results

Three acylated analogues were produced: quercetin 4′-oleate (C33H42O8), quercetin 3′,4′-dioleate (C51H74O9) and quercetin 7,3′,4′-trioleate (C69H106O10). Their identities were confirmed with UPLC–ESI–MS and 1H NMR analyses. The effects of temperature, duration and molar ratio of substrates on the bioconversion yields varied across conditions. The regioselectivity of the acylated quercetin analogues was affected by the molar ratio of substrates. TLC showed the acylated analogues had higher lipophilicity (152% increase) compared to quercetin. Partition coefficient (log P) of quercetin 4′-oleate was higher than those of quercetin and oleic acid. Quercetin 4′-oleate was also stable over 28 days of storage.

Conclusions

Quercetin oleate esters with enhanced lipophilicity can be produced via lipase-catalyzed reaction using C. antarctica lipase B to be used in topical applications.
  相似文献   

11.
Two different immobilisation techniques for lipases were investigated: adsorption on to Accurel EP-100 and deposition on to Celite. The specific activities were in the same order of magnitude, 2.9 (mol min–1 mg protein) when Celite was used as support and 2.3 (mol min–1 mg–1 protein) when Accurel EP-100 was used as support, even if the amount of lipase loaded differed by 2 orders of magnitude. Immobilisation on Accurel EP-100 was the preferred technique since 40–100 times more protein can be loaded/per g carrier, thus yielding a more active catalyst. The water activity profiles in lipase catalysed esterification were influenced by the amount of protein adsorbed to Accurel EP-100. Higher protein loading (40 mg g–1) resulted in a bell-shaped water activity profile with highest specific activity (6.1 mol min–1 mg–1 protein) at a w=0.11, while an enzyme preparation with low protein loading (4 mg g–1) showed highest specific activity at a w=0.75.  相似文献   

12.
A thermostable lipase produced by a thermophilic Bacillus sp. J33 was purified to 175-fold with 15.6% recovery by ammonium sulphate and Phenyl Sepharose column chromatography. The enzyme is a monomeric protein having molecular weight of 45 kDa. It hydrolyzes triolein at all positions. The fatty acid specificity of lipase is broad with little preference for C12 and C4. The Km and Vmax for lipase with pNP-laurate as substrate was calculated to be 2.5 mM and 0.4 M min-1 ml-1 respectively. The immobilized enzyme was stable for 12 h at 60°C. Polyhydric alcohols such as ethylene glycol (2.5 M), sorbitol (2.5 M) and glycerol (2.5 M) were used as thermostabilizers. Lipase acquired a remarkable stability, since no deactivation occurred at 70°C for 150 min in the presence of additives.  相似文献   

13.
Surface residues have a significant impact on the enantioselectivity of lipases. But the molecular basis of this has never been explained. In this work, transition state complexes of Rhizomucor miehei lipase (RmL) and (R)- or (S)-n-butyl 2-phenxypropinate were studied using molecular dynamics. According to comparison between B-factor of the two simulated complexes, the β 1β 2 loop and α 2 helix were considered the enantioselectivity-determining domains of RmL. Interaction analysis of these domains suggested an Asp61–Arg86 electrostatic interaction linking the loop and helix strongly impacting enantioselectivity of RmL. Modification of Arg86 by 1, 2-cyclohexanedione weakening this interaction decreased the E ratio from 6 to 1, modification by 1-iodo-2, 3-butanedione covalently bonding Asp61 and Arg86 strengthening the interaction increased the E ratio to 45. Dynamics simulation and energy calculation of the modified lipases also displayed corresponding decreases or increases of enantioselectivity.  相似文献   

14.
15.
16.
The transesterification of coconut oil with ethanol catalyzed by Burkholderia cepacia lipase immobilized on polysiloxane–polyvinyl alcohol was performed in a continuous flow. The experimental design consisted of a two-stage packed-bed reactor incorporating a column with cationic resin (Lewatit GF 202) to remove the glycerol formed as by-product and the reactor performance was quantified for three different flow rates corresponding to space-times from 10 to 14 h. The influence of space-time on the ethyl ester (FAEE) concentrations, yields and productivities was determined. The reactor operation was demonstrated for space-time of 14 h attaining FAEE concentrations of 58.5 ± 0.87 wt%, FAEE yields of 97.3 ± 1.9 % and productivities of 41.6  ± 1.0 mgester g medium ?1  h?1. Biodiesel purified samples showed average kinematic viscosity values of 5.5 ± 0.3 mm2 s?1 that meet the criteria established by the American National Standard ASTM (D6751). The immobilized lipase was found to be stable regarding its morphological and catalytic characteristics, showing half-life time (t 1/2) around 1540 h. The continuous packed-bed reactor connected in series with simultaneous glycerol removal has a great potential to attain high level of transesterification yields, raising biodiesel productivity.  相似文献   

17.
Measurement of lipase (triacylglycerol acylhydrolase; EC 3.1.1.3) activity in tissue extracts often poses problems due to the inhibitors released during homogenization. The present investigation provides a first report on the localization of lipase activity in viable plant protoplasts isolated from the cotyledons of germinating seeds of sunflower, cotton and peanut by fluorescence microscopy, using a lipase specific, 'glycerol-derived' synthetic substrate, i.e., 1,2-O-dilauryl-rac-3-glycero-glutaric acid-resorufin ester, commonly used for in vitro assays. Due to its lipophilicity, this chromogenic substrate readily permeates plasma membrane of plant protoplasts. Subsequent lipase action leads to cleavage of this substrate to release resorufin, which can be visualized due to emission of red fluorescence (max excitation – 567 nm; max emission – 584.6 nm) at its intracellular locations.  相似文献   

18.
An extracellular lipase produced by the sapstaining fungus Ophiostoma piceae 387N in a liquid medium was purified to homogeneity using ammonium sulphate and acetone fractionation, hydrophobic interaction and anion exchange chromatography. The overall purification based on lipase activity was 5200-fold with a yield of 26%. The molecular mass of the lipase was 35kDa, as determined by sodium dodecyl sulphate–polyacrylamide gel electrophoresis (SDS-PAGE), and 37 kDa, as measured by size exclusion chromatography. The purified enzyme was resolved as three bands at pI values of 4.3, 4.1 and 3.8 in IEF (isoelectric focusing) gels. Lipolytic stain demonstrated that all three bands were lipolytically active. The N-terminal amino acid sequence was determined asD1-V2-S3-V4-T5-T6-T7-D8-I9-D10-A11-L12-A13-F14-F15-T16-Q17-W18-A19-G20 . The lipase was shown to be glycosylated, containing 10.1% carbohydrate. The lipase was stable between pH 4 and pH 8 and at temperatures below 40°C. The lipase activity had a pH optimum of approximately 5 and a temperature optimum of 30°C. The enzyme activity was not influenced by N-ethylmaleimide, -mercaptoethanol or dithiothreitol, was enhanced by Ca2+ or Mn2+, but was severely inhibited by Hg2+, Fe3+, butyric acid, caproic acid, diethyl pyrocarbonate, and diethyl p-nitrophenyl phosphate. The lipase hydrolysed mainly triglycerides, although some activity was measured on waxes and cholesteryl esters. It belongs to a group of 1 (3) positional specific lipases. It showed little activity for substrates with short chain fatty acids (C2–C6), but demonstrated high specificity for substrates with intermediate and long chain fatty acid residues (C10–C18).  相似文献   

19.
A lipase with a high molecular weight was purified from Chromobacterium viscosum by chromatography using the Amberlite CG–50 and Sephadex G–75. The purified lipase (Lipase A) was found to be homogeneous by disc electrophoresis.

Lipase A had an optimum pH around 7 for lipolysis of olive oil and the enzyme was stable at the range of pH 4 to 9 and below 50°C. Zn2+, Cu2+, Fe3+ and high concentrations of l-cysteine, iodoacetic acid and NBS had remarkable inhibitory effects. Bile salts were activator. Lipase A was more active on water insoluble esters than water soluble esters. The isoelectric point of the enzyme was pH 4.7.  相似文献   

20.
Microorganisms associated with marine sponges are potential resources for marine enzymes. In this study, culture-independent metagenomic approach was used to isolate lipases from the complex microbiome of the sponge Ircinia sp. obtained from the South China Sea. A metagenomic library was constructed, containing 6568 clones, and functional screening on 1 % tributyrin agar resulted in the identification of a positive lipase clone (35F4). Following sequence analysis 35F4 clone was found to contain a putative lipase gene lipA. Sequence analysis of the predicted amino acid sequence of LipA revealed that it is a member of subfamily I.1 of lipases, with 63 % amino acid similarity to the lactonizing lipase from Aeromonas veronii (WP_021231793). Based on the predicted secondary structure, LipA was predicted to be an alkaline enzyme by sequence/structure analysis. Heterologous expression of lipA in E. coli BL21 (DE3) was performed and the characterization of the recombinant enzyme LipA showed that it is an alkaline enzyme with high tolerance to organic solvents. The isolated lipase LipA was active in the broad alkaline range, with the highest activity at pH 9.0, and had a high level of stability over a pH range of 7.0–12.0. The activity of LipA was increased in the presence of 5 mM Ca2+ and some organic solvents, e.g. methanol, acetone and isopropanol. The optimum temperature for the activity of LipA is 40 °C and the molecular weight of LipA was determined to be ~30 kDa by SDS-PAGE. LipA is an alkaline lipase and shows good tolerance to some organic solvents, which make it of potential utility in the detergent industry and enzyme mediated organic synthesis. The result of this study has broadened the diversity of known lipolytic genes and demonstrated that marine sponges are an important source for new enzymes.  相似文献   

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