Acyl migration during deacylation of phospholipids rich in docosahexaenoic acid (DHA): an enzymatic approach for evidence and study

Non-enzymatic acyl migration could be counter-productive for the preparation of structured phospholipids with docosahexaenoic acid (DHA) at a designated position. Therefore enzymatic approaches have been developed to investigate acyl migration. First, acyl migration from sn-2 to sn-1 position has been set into relief by a three step enzymatic method using a typo-selective lipase, a phospholipase A2 and a non-selective lipase. The effect of reaction temperature on acyl migration from sn-2 to sn-1 was monitored: lowering the reaction temperature from 40 to 30°C allowed a reduction of DHA migration rate of 40%. Secondly, acyl migration from sn-1 to sn-2 position was negligible. This last result was obtained through the study of structured phosphatidylcholine selective deacylation using a phospholipase A2.     

A lipase of Aeromonas hydrophila showing nonhemolytic phospholipase C activity

Extracellular lipase activity detected on tributyrin agar has been identified in a cosmid clone, JMP3084, constructed from the chromosome of Aeromonas hydrophila and vector pHC79. This lipase, named apl-1, also exhibits nonhemolytic phospholipase C activity on lecithin and p-nitrophenylphosphorylcholine. Subcloning of the cosmid JMP3084 with partial Sau3a1 digestion localized the lipase gene to a 3.4-kb DNA fragment. Southern blot analysis shows the gene apl-1 to exist in single copy on the A. hydrophila chromosome. Expression of apl-1 in the pT7 system identified a single protein of molecular weight 70 kDa. Nucleotide sequencing of apl-1 has identified an open reading frame of 2055 bases predicting a protein of 73 kDa. The presence of an amino terminal signal sequence of 18 amino acids accounts for this molecular weight disparity. Further analysis of the lipase amino acid sequence revealed the presence of a classical serine active lipase site (Gly-X-Ser-X-Gly) located between residues 561 and 570. The A. hydrophila chromosomal copy of apl-1 has been inactivated by use of the mutagenesis vector pJP5603, resulting in the complete removal of phospholipase C activity and lowered levels of lipase activity detected on tributyrin agar.     

Regulation of Expression of the Nonhemolytic Phospholipase C of Burkholderia cepacia

Burkholderia cepacia is an opportunistic pathogen that causes serious pulmonary infections in cystic fibrosis patients. We have purified and partially characterized one potential virulence factor for the organism—a nonhemolytic phospholipase C—and we studied the effect of iron restriction and choline and phosphate concentrations on the expression of phospholipase C. Iron limitation did not affect expression, the effect of choline was variable, and high phosphate concentrations repressed expression. Experiments with heat-treated spent culture supernatants suggested that autoinducers affected the expression of the phospholipase and two other potential virulence factors, a protease and a lipase. We screened 26 B. cepacia isolates for autoinducer activity: 11 induced violacein production in the autoinducer-deficient mutant Chromobacterium violaceum CV026. Spent supernatants from two strains, one that was positive in the C. violaceum assay and one that was negative, were tested for inducing early expression of phospholipase C, protease, and lipase in homologous and heterologous cultures. Expression of all three enzymes was increased or induced at an earlier stage in the growth curve in every case, suggesting not only that autoinducers were involved in the regulation of the expression of these enzymes, but also that the autoinducers were of two different classes. Received: 13 May 1999 / Accepted: 14 June 1999     

A Nonhemolytic Phospholipase C from Burkholderia cepacia

Burkholderia cepacia is an opportunistic pathogen that causes serious pulmonary infections in cystic fibrosis patients. Although several potential virulence factors—a protease, lipase, and two phospholipases C (one hemolytic and one nonhemolytic)—have been identified, only two, the protease and the lipase, have been described in detail. The goal of this study was to purify and characterize a nonhemolytic phospholipase C secreted by B. cepacia strain Pc224c. The enzyme was concentrated from culture supernatants and purified by polyacrylamide gel electrophoresis. The 54-kDa protein was stable in the presence of sodium dodecyl sulfate (up to 10%) and at 4°, 22°, and 37°C; it was, however, inactivated at 100°C. The enzyme bound to glass, chromatography matrices, and polyvinylidene difluoride and cellulose membranes, suggesting that it is hydrophobic.  In a genetic approach, primers based on conserved sequences of a B. cepacia Pc69 hemolytic phospholipase C and both the Pseudomonas aeruginosa hemolytic and nonhemolytic proteins were designed to identify the Pc224c nonhemolytic phospholipase C gene. One polymerase chain reaction product was identified; it was sequenced and the sequence compared with sequences in the BLAST database. The best match was the Pseudomonas aeruginosa hemolytic phospholipase C. Ten additional B. cepacia strains were screened for the gene by Southern hybridization; five had the 4-kb band, suggesting that these strains have a similar form of the PLC gene. Nine of the ten strains reacted with the probe, suggesting that similar sequences were present, but in another form. Received: 13 October 1998 / Accepted: 6 November 1998     

Changes in the binding and inhibitory properties of urea/triazine-type herbicides upon phospholipid and galactolipid depletion in the outer monolayer of thylakoid membranes

The binding characteristics and the inhibitory power of atrazine and DCMU towards uncoupled electron flow activity were studied in acyl lipid-depleted thylakoid membranes from atrazine-susceptible and-resistant biotypes of Solanum nigrum L. For this purpose, phospholipase A₂ from Vipera russelli and the lipase from Rhizopus arrhizus were used to obtain a selective lipid class (phospholipids or galactolipids) depletion which was restricted to the outer monolayer. Neither phospholipid nor galactolipid removal affected the dissociation constant and the number of binding sites of atrazine. In contrast, the dissociation constant of DCMU was increased in phospholipid-depleted thylakoid membranes but remained unchanged after galactolipid depletion. The number of DCMU binding sites decreased significantly after both lipase treatments, but only in the resistant biotype. The inhibitory effectiveness of the herbicide was either decreased or increased (to different extents) depending on the lipid class which was removed from the membrane and on the biotype considered. These results are discussed with reference to the possible conformational changes of the 32 kDa herbicide-binding polypeptide occurring after lipase treatments.Abbreviations Atrazine 2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine - BSA bovine serum albumin - DCMU diuron, 3-(3,4-dichlorophenyl)-1,1-dimethylurea - DGDG digalactosyldiacylglycerol - LRa lipase from Rhizopus arrhizus - MGDG monogalactosyldiacylglycerol - PC phosphatidylcholine - PG phosphatidylglycerol - PLA₂ phospholipase A₂ - R atrazine-resistant - S atrazinesusceptible     

The effects of mepacrine and p-bromophenacyl bromide on arachidonic acid release in human platelets

Two inhibitors of thrombin-stimulated arachidonic acid release from platelets, p-bromophenacyl bromide and mepacrine, were examined for their ability to inhibit the phospholipase C-diglyceride lipase pathway. This pathway involves hydrolysis of phosphatidylinositol to diglyceride, followed by release of arachidonate from diglyceride, and has been proposed as an alternative or addition to phospholipase A₂ as a mechanism for arachidonate release. p-Bromophenacyl bromide, a potent alkylating agent, was shown to cause a time-dependent inhibition of phosphatidylinositol-specific phospholipase C activity in crude platelet extracts; the inhibition was >90% after 15 min incubation with 100 μmp-bromophenacyl bromide. However, p-bromophenacyl bromide was also shown to destroy about one-half of the titratable sulfhydryl groups in whole platelets under similar conditions. The lack of specificity of p-bromophenacyl bromide was further demonstrated by our finding that thrombin-stimulated serotonin release was also inhibited by conditions inhibiting arachidonate release and that diglyceride lipase activity was decreased by higher levels of p-bromophenacyl bromide. Mepacrine was found to inhibit the activity of phosphatidylinositol-specific phospholipase C and had a greater effect at low substrate concentrations. The loss of [¹⁴C]arachidonate from both endogenous phosphatidylinositol and phosphatidylcholine in intact platelets was also inhibited. Thrombin-stimulated serotonin release was impaired by mepacrine also but only at a concentration 10-fold greater than that required to prevent arachidonate release. Thus we have shown that these two agents which inhibit arachidonate release are inhibitors of the phosphatidylinositol-specific phospholipase C-diglyceride lipase pathway. The multiple effects produced by both compounds limit their utility as agents to examine the source and mechanism of arachidonate release.     

Effects of Delipidation on Proton Translocation and ATPase Activity in Beef Heart Electron Transport Particles

Delipidation of beef heart electron transport particles with phospholipase A₂ has been examined. When the particles were treated with the lipase and subjected to a low bovine serum albumin wash, ATPase activity was unaffected as was the lipid/protein ratio of the particles. However, energisation by ATP/Mg²⁺ was abolished. Furthermore, unsaturated but not saturated fatty acids discharged the steady-state ATP-driven membrane potential of control samples. When the phospholipase A₂ hydrolysis products were removed, inhibition of energy-linked reactions in the lipid-depleted particles was still observed and was interpreted in terms of non-specific leaks in the vesicle membranes, and ‘specific’ leaks through impaired H⁺-ATPase complexes. ATPase activity was less susceptible to delipidation than energisation but was, nevertheless, strongly inhibited at 50 percent lipid depletion.

Spin label studies indicated a decrease in the fluidity of particle membranes accompanying delipidation. Moreover, the discontinuity seen in Arrhenius plots of ATPase activity was shifted from 17°C (control) to 22°C at 50 percent phospholipid depletion. The data are consistent with a release of unsaturated fatty acids by phospholipase A₂ rendering the transport particles both leakier and the membranes less fluid than controls.     

Phospholipases of Leptospira. I. Presence of phospholipase A1 and lysophospholipase in Leptospira biflexa

The hydrolysis of phosphatidylethanolamine, phosphatidylcholine, lysophosphatidylcholine, and trioleoylglycerol by Leptospira biflexa strain Urawa was studied in vitro. Phospholipase A₁ was identified by the formation of ³²P- and ¹⁴C-labeled lyso-derivatives from ³²P-phosphatidylcholine, ³²P-phosphatidylethanolamine, or 1-acyl-2-[1-¹⁴C]oleoyl-sn-glycero-3-phosphorylcholine. Phospholipase A₁ activity was independent of lipase in the microorganism since ¹⁴C-labeled trioleoylglycerol was scarcely attacked under the same conditions in which the phospholipids were hydrolyzed. Lysophospholipase activity was also demonstrated using ³²P- and non-labeled lysophosphatidylcholine. The activity of phospholipase A₁ was found in a broad range of pH but no optimal pH was determined. The pH optimum of lysophospholipase was 8.0. Both enzymes were labile to heat. Phospholipase C activity, however, could not be detected because no radioactive di- and monoacylglycerol was found in the experiment with 1-acyl-2-[1-¹⁴C]-oleoyl-sn-glycero-3-phosphorylcholine as the substrate. It was inferred that phosphatidylethanolamine, which was the major component of phospholipids in leptospirae, was hydrolyzed serially by phospholipase A (A₁ and/or A₂?) and lysophospholipase to glycerophosphorylethanolamine via 2-acyl-type-lyso-derivative as one metabolic pathway of the substrate.     

Purification and Some Properties of a Fungal Lipase Preparation Used for Milk Flavouring

Intracellular lipase of a strain of Rhizopus fungus which is effective for producing a milk flavor was purified and fractionated into two components, I and II, by DEAE Sephadex A-50 column chromatography. They both proved homogeneous by electrophoresis and ultracentrifugal analysis. The sedimentation coefficient was respectively calculated to be 5.8×10^?13 for lipase I, and to be 2.2×10^?13 for lipase II. From substrate specificity, it was found that lipase I was an ordinary lipase hydrolyzing olive oil and tributyrin favourably, while, II, rather, a special lipase having a high affinity towards tricaprylin. They, also, respectively had an apparent phospholipase activity on soy-lecithin and, clearing activity on chylomicron prepared from olive oil and human serum. Their mode of action, and the effect of metals and emulsifying agents on their activity are also presented.     

Toxinogenicity and markers of pathogenicity of Pseudomonas aeruginosa strains isolated from patients with tumor diseases

Potential virulence factors (elastase, proteinase, lipase, phospholipase C, alginate) as well as surface properties (hydrophobicity, motility) were determined in 103Pseudomonas aeruginosa strains isolated from patients with cancer. Nontypable strains were the dominant group (60%), followed by serotypes O11 (17%), O12 (7%) and O4 (5%). Seventy-one strains (69%) produced high level of elastase (10–60 mg/L), 87% of the strains possessed high activity of proteinase (bacterial) (10–250 mg/L) and 69% of the strains demonstrated higher level of lipase (20–150 U/mL); these elevated levels of enzymes were associated mainly with nontypable strains. On the other hand, 79% of the strains did not produce or produced only a low level of phospholipase C and 60% of isolates did not manifest any or very low production of alginate. Hydrophobicity demonstrated by adherence of the bacteria to xylene was shown by 69% of strains; 94% of strains aggregated with ammonium sulfate. Motility in the range of 31–80 mm was found in 76 strains (74%). The considerable virulence of testedP. aeruginosa strains was confirmed. The nontypable strains manifested the most frequent group with high level of elastase, proteinase, lipase, hydrophobicity and motility.     

Isolation of a novel lipase producing fungal isolate Aspergillus fumigatus and production optimization of enzyme

Abstract

Fungal lipases occupy a place of prominence among biocatalysts owing to their novel, multifold applications and resistance to high temperature and other operational conditions. In the present study, Aspergillus fumigatus isolated from oil-contaminated soil produced good amount of lipase activity with galactose (1%) as carbon source and peptone (0.1%) as nitrogen source after 72?h of incubation in the production medium at 45?°C and pH 10.0. The isolated enzyme was found to give its optimum reaction temperature at 40?°C and pH 9.0 with the substrate used as p-nitrophenyl benzoate. The activity of lipase was inhibited by the presence of metal ions. A 6.68-fold increase for lipase production was obtained by one variable at a time. Based on the findings of present study, lipase of A. fumigatus is a potential lipase and a candidate for industrial applications such as bioremediation, detergent, leather and pharmaceutical industries.     

Gene cloning,expression and characterization of a cold-adapted lipase from a psychrophilic deep-sea bacterium Psychrobacter sp. C18

A psychrophilic bacterium Psychrobacter sp. C18 previously isolated from the Southern Okinawa Trough deep-sea sediments showed extracellular lipolytic activity towards tributyrin. A genomic DNA library was constructed and screened to obtain the corresponding lipase gene. The sequenced DNA fragment contains an open reading frame of 945 bp, which was denoted as the lipX gene, from which a protein sequence LipX was deduced of 315 amino acid residues with a molecular mass of 35,028 Da. This protein contained the bacterial lipase GNSMG (GxSxG, x represents any amino acid residue) and HG consensus motifs. The recombinant pET28a(+)/lipX gene was overexpressed in heterologous host Escherichia coli BL21 (DE3) cells to overproduce the lipase protein LipX_His with a 6× histidine tag at its C-terminus. Nickel affinity chromatography was used for purification of the expressed recombinant lipase. The maximum lipolytic activity of the purified recombinant lipase was obtained at temperature of 30°C and pH 8.0 with p-nitrophenyl myristate (C14) as a substrate. Thermostability assay indicated that the recombinant LipX_His is a cold-adapted lipase, which was active in 10% methanol, ethanol, acetone and 30% glycol, and inhibited partially by Zn²⁺, Co²⁺, Mn²⁺, Fe³⁺ and EDTA. Most non-ionic detergents, such as DMSO, Triton X-100, Tween 60 and Tween 80 enhanced the lipase activity but 1% SDS completely inhibited the enzyme activity. Additionally, the highest lipolytic rate of the recombinant LipX_His lipase was achieved when p-nitrophenyl myristate was used as a substrate, among all the p-nitrophenyl esters tested.     

In Vitro Evaluation of Phospholipase,Proteinase, and Esterase Activities of <Emphasis Type="Italic">Candida parapsilosis</Emphasis> and <Emphasis Type="Italic">Candida metapsilosis</Emphasis>

The aim of this study is to characterize extracellular phospholipase, proteinase, and esterase activities of Candida parapsilosis and C. metapsilosis isolated from clinical sources. Using PCR-restriction fragment length polymorphism (PCR–RFLP) of the secondary alcohol dehydrogenase (SADH) gene fragment, we identified 20 as C. parapsilosis and 11 as C. metapsilosis from 31 isolates of C. parapsilosis species complex. No C. orthopsilosis was identified. A significantly high isolation frequency of C. metapsilosis (35.5%) was observed. Subsequent evaluation of enzymatic profile showed that 90.5% of C. parapsilosis and 91.7% of C. metapsilosis isolates were phospholipase producers. No difference in phospholipase activity was observed between two species. In terms of proteinase, 81.0% of C. parapsilosis and 83.3% of C. metapsilosis isolates were positive. A higher level of proteinase activity was detected in C. parapsilosis. A remarkably high proportion of both C. parapsilosis and C. metapsilosis isolates exhibited strong phospholipase and proteinase activities, suggesting that the production of these two enzymes might be common for them. On the other hand, both species similarly displayed rare esterase activity, with only one C. parapsilosis and two C. metapsilosis isolates being positive. Our data may further add to the confusion concerning the hydrolytic enzymatic activities of the C. parapsilosis complex, and a wider collection of isolates and standardized methods may help to address the issue.     

Study of histamine binding to h2-receptors of gastric mucosa membranes of the frogRana ridibunda

The stability was studied of histamine H₂-receptors and of histamine-sensitive adenylyl cyclase of the crude membrane fraction of the gastric mucosa of the frogRana ridibunda to the action of exogenous hydrolases, lipase (phospholipase C), protease (papain), glycosidase (sialidase), and blockers of free SH-groups (iodoacetate and N-ethylmaleimide). The action of these agents on the free and histamine-occupied H₂ -receptors of the frog gastric mucosa was analyzed by the amount of the bound ligand. The histamine binding to receptor increased the receptor vulnerability to the effect of phospholipase C, papain, and SH-reagents. Study of the action of hydrolases on the basal and stimulated, histamine-sensitive adenylyl cyclase activity revealed that phospholipase C caused a decrease of the basal and all kinds of the stimulated activity of adenylyl cyclase, while papain and sialidase only prevented the histamine stimulation of the enzyme. The obtained data indicate changes of the surface exposure of functional groups during the specific ligand-receptor interaction.     

Study of histamine binding to h2-receptors of gastric mucosa membranes of the frogRana ridibunda

The stability was studied of histamine H₂-receptors and of histamine-sensitive adenylyl cyclase of the crude membrane fraction of the gastric mucosa of the frogRana ridibunda to the action of exogenous hydrolases, lipase (phospholipase C), protease (papain), glycosidase (sialidase), and blockers of free SH-groups (iodoacetate and N-ethylmaleimide). The action of these agents on the free and histamine-occupied H₂-receptors of the frog gastric mucosa was analyzed by the amount of the bound ligand. The histamine binding to receptor increased the receptor vulnerability to the effect of phospholipase C, papain, and SH-reagents. Study of the action of hydrolases on the basal and stimulated, histamine-sensitive adenylyl cyclase activity revealed that phospholipase C caused a decrease of the basal and all kinds of the stimulated activity of adenylyl cyclase, while papain and sialidase only prevented the histamine stimulation of the enzyme. The obtained data indicate changes of the surface exposure of functional groups during the specific ligand-receptor interaction.     

Development of recombinant Aspergillus oryzae whole-cell biocatalyst expressing lipase-encoding gene from Candida antarctica

To expand the industrial applications of Candida antarctica lipase B (CALB), we developed Aspergillus oryzae whole-cell biocatalyst expressing the lipase-encoding gene from C. antarctica. A. oryzae niaD300, which was derived from the wild type strain RIB40, was used as the host strain. The CALB gene was isolated from C. antarctica CBS6678 and expression plasmids were constructed with and without secretion signal peptide. The lipase gene was expressed under the control of improved glaA and pNo-8142 promoters of plasmids pNGA142 and pNAN8142, respectively. The Southern blot analysis demonstrated the successful integration of the CALB gene in the genome of A. oryzae. To determine the role of signal peptide, the expression plasmids were constructed with homologous and heterologous secretion signal sequences of triacylglycerol lipase gene (tglA) from A. oryzae and lipase B (CALB) from C. antarctica, respectively. The C-terminal FLAG tag does not alter the catalytic properties of the lipase enzyme and Western blotting analysis using anti-FLAG antibodies demonstrated the presence of cell wall and membrane bound lipase responsible for the biocatalytic activity of the whole-cell biocatalyst. The resultant recombinant A. oryzae was immobilized within biomass support particles (BSPs) made of polyurethane foam (PUF) and the BSPs were successfully used for the hydrolysis of para-nitrophenol butyrate (p-NPB) and for the optical resolution of (RS)-1-phenyl ethanol by enantioselective transesterification with vinyl acetate as acyl donor.     

Sequence Analysis of Amplified DNA Fragments Containing the Region Encoding the Putative Lipase Substrate-Binding Domain and Genotyping of Aeromonas hydrophila

DNA fragments were amplified by PCR from all tested strains of Aeromonas hydrophila, A. caviae, and A. sobria with primers designed based on sequence alignment of all lipase, phospholipase C, and phospholipase A1 genes and the cytotonic enterotoxin gene, all of which have been reported to have the consensus region of the putative lipase substrate-binding domain. All strains showed lipase activity, and all amplified DNA fragments contained a nucleotide sequence corresponding to the substrate-binding domain. Thirty-five distinct nucleotide sequence patterns and 15 distinct deduced amino acid sequence patterns were found in the amplified DNA fragments from 59 A. hydrophila strains. The deduced amino acid sequences of the amplified DNA fragments from A. caviae and A. sobria strains had distinctive amino acids, suggesting a species-specific sequence in each organism. Furthermore, the amino acid sequence patterns appear to differ between clinical and environmental isolates among A. hydrophila strains. Some strains whose nucleotide sequences were identical to one another in the amplified region showed an identical DNA fingerprinting pattern by repetitive extragenic palindromic sequence-PCR genotyping. These results suggest that A. hydrophila, and also A. caviae and A. sobria strains, have a gene encoding a protein with lipase activity. Homologs of the gene appear to be widely distributed in Aeromonas strains, probably associating with the evolutionary genetic difference between clinical and environmental isolates of A. hydrophila. Additionally, the distinctive nucleotide sequences of the genes could be attributed to the genotype of each strain, suggesting that their analysis may be helpful in elucidating the genetic heterogeneity of Aeromonas.     

Production and characterization of a cold-active and n-hexane activated lipase from a newly isolated Serratia grimesii RB06-22

Abstract

A lipase-producing bacterium isolated from raw milk was identified as Serratia grimesii based on 16S rRNA sequence analysis. The extracellular lipase was partially purified by ammonium sulfate precipitation and ultrafiltration. Maximal activity was observed at 10°C, the optimum pH was 8.0 and the enzyme was stable at 5–30°C for 1 h. The K_m and V_max values were 1.7 mM and 0.3 mM/min respectively. It was found that the lipase had the highest hydrolytic activity towards sunflower oil and soybean oil. CaCl₂ had a stimulatory effect on lipase activity, while EDTA and iodoacetic acid slightly inhibited the lipase activity and the enzyme was strongly inhibited by PMSF. The enzyme was compatible with various non-ionic surfactants as well as sodium cholate and saponin. In addition, the enzyme was relatively stable towards oxidizing agents. This lipase exhibited maximum activity in 35% n-hexane retaining about 2191% activity for 1 h.     

Purification and Biochemical Characterization of Digestive Lipase in Whiteleg Shrimp

Penaeus vannamei lipase was purified from midgut gland of whiteleg shrimp. Pure lipase (E.C. 3.1.1.3) was obtained after Superdex 200 gel filtration and Resource Q anionic exchange. The pure lipase, which is a glycosylated molecule, is a monomer having a molecular mass of about 44.8 kDa, as determined by SDS-PAGE analysis. The lipase hydrolyses short and long-chain triacylglycerols and naphthol derivates at comparable rates. A specific activity of 1787 U mg⁻¹ and 475 U mg⁻¹ was measured with triolein and tributyrin as substrates, respectively, at pH 8.0 and 30°C in the absence of colipase. The lipase showed a K _{m, app} of 3.22 mM and k _{cat, app}/K _{m, app} of 0.303 × 10³ mM⁻¹ s⁻¹ using triolein as substrate. Natural detergents, such as sodium deoxycholate, act as potent inhibitors of the lipase. This inhibition can be reversed by adding fresh oil emulsion. Result with tetrahydrolipstatin, an irreversible inhibitor, suggests that the lipase is a serine enzyme. Peptide sequences of the lipase were determined and compared with the full-length sequence of lipase which was obtained by the rapid amplification of cDNA ends method. The full cDNA of the pvl was 1,186 bp, with a deduced protein of 362 amino acids that includes a consensus sequence (GXSXG) of the lipase superfamily of α/β-hydrolase. The gene exhibits features of conserved catalytic residues and high homology with various mammalian and insect lipase genes. A potential lid sequence is suggested for pvl.