Lipase Complex Research Articles

Exploring lipidomic profiles and their correlation with hormone receptor and HER2 status in breast cancer.

Dysregulated lipid metabolism promotes the progression of various cancer types, including breast cancer. The present study aimed to explore the lipidomic profiles of patients with breast cancer, providing insights into the correlation between lipid compositions and tumor subtypes characterized by hormone receptor (HR) and human epidermal growth factor receptor 2 (HER2) status. Briefly, 30 patients with breast cancer were categorized into four groups based on their HR and HER2 status: HR+ no HER2 expression (HER2-0), HR+ HER2-low; HR+ HER2-positive (pos) and HR- HER2-pos. The lipidomic profiles of these patients were analyzed using high-throughput liquid chromatography-mass spectrometry. The data were processed through principal component analysis (PCA), partial least squares-discriminant analysis (PLS-DA) and random forest (RF) classification to assess the lipidomic variations and significant lipid features among these groups. The profiles of the lipids, particularly triglycerides (TG) such as TG(16:0-18:1-18:1)+NH4, were significantly different across the groups. PCA and PLS-DA identified unique lipid profiles in the HR+ HER2-pos and HR+ HER2-0 groups, while RF highlighted phosphatidylinositol-3,4,5-trisphosphate(21:2)+NH4 as a crucial lipid feature for accurate patient grouping. Advanced statistical analysis showed significant correlations between lipid carbon chain length and the number of double bonds within the classifications, providing insights into the role of structural lipid properties in tumor biology. Additionally, a clustering heatmap and network analysis indicated significant lipid-lipid interactions. Pathway enrichment analysis showed critical biological pathways, such as the 'Assembly of active LPL and LIPC lipase complexes', which has high enrichment ratio and statistical significance. In conclusion, the present study underscored that lipidomic profiling is crucial in understanding the metabolic alterations associated with different breast cancer subtypes. These findings highlighted specific lipid features and interactions that may serve as potential biomarkers for breast cancer classification and target pathways for therapeutic intervention. Furthermore, advanced lipidomic analyses can be integrated to decipher complex biological data, offering a foundation for further research into the role of lipid metabolism in cancer progression.

Crystal structure of Staphylococcus aureus lipase complex with unsaturated petroselinic acid.

Staphylococcus aureus produces large amounts of toxins and virulence factors. In patients with underlying diseases or compromised immune systems, this bacterium can lead to severe infections and potentially death. In this study, the crystal structure of the complex of S. aureus lipase (SAL), which is involved in the growth of this bacterium, with petroselinic acid (PSA), an inhibitor of unsaturated fatty acids, was determined by X-ray crystallography. Recently, PSA was shown to inhibit S. aureus biofilm formation and the enzymatic activity of SAL. To further characterize the inhibitory mechanism, we determined the half-inhibitory concentration of SAL by PSA and the crystal structure of the complex. The IC50 of the inhibitory effect of PSA on SAL was 3.4 μm. SAL and PSA inhibitors were co-crystallized, and diffraction data sets were collected to 2.19 Å resolution at SPring-8 to determine the crystal structure and elucidate the detailed structural interactions. The results show that the fatty acid moiety of PSA is tightly bound to a hydrophobic pocket extending in two directions around the catalytic residue Ser116. Ser116 was also covalently bonded to the carbon of the unsaturated fatty acid moiety, and an oxyanion hole in SAL stabilized the electrons of the double bond. The difference in inhibitory activity between PSA and ester compounds revealed a structure-activity relationship between SAL and PSA. Additional research is required to further characterize the clinical potential of PSA.

Enhanced Esterification Activity and Thermostability of Imprinted Poly(Ethylene Glycol)-Lipase Complex

Although the range of applications for enzymatic reactions in organic solvents is <br /> rapidly expanding, this study focused on the enzymatic activity in the esterification of <br /> lauric acid with benzyl alcohol, and thermostability of lipase using poly(ethylene glycol) <br /> (PEG)-lipase complex and molecular imprinting techniques. The catalytic activity was <br /> enhanced through molecular imprinting and the PEG-lipase complex. The imprinting operation was particularly effective for catalytic activity after forming the PEG-lipase complex. The kinetic analysis of the lipase-catalyzed esterification revealed that the increase in esterification rate with imprinted lipases was mainly due to the higher maximum rate achieved by the system. The thermostability of the lipases was significantly improved by imprinting at all temperatures (50~70 °C). After forming a PEG-lipase complex, the imprinted lipase exhibited much higher reactivity and thermostability compared to the native lipase and the imprinted PEG-lipase complex.

QSAR model of pancreatic lipase inhibition by phenolic acids and their derivatives based on machine learning and multi-descriptor strategy

Inhibition of pancreatic lipase can be effective in controlling or treating obesity. Phenolic acids have good pancreatic lipase inhibitory effects and are widely found in plants. The identification of phenolic acids and their derivatives that can efficiently inhibit pancreatic lipase has attracted widespread attention. Therefore, it is crucial to screen natural pancreatic lipase inhibitors efficiently by establishing quantitative structure-activity relationships (QSAR) models. In this study, machine learning was used to perform multiple computational analyses of 28 phenolic acids and their derivatives with pancreatic lipase inhibitory activity, and multiple QSAR models were established. Molecular parameters were analyzed, IC50 was predicted, and molecular docking and molecular dynamics simulations analysis were done for the screened natural compounds. The results showed that the model with the highest level of accuracy is the 2D-3D mix model with a numerator parameter value of 8 (R2fitting of 0.9537 and MAE of 0.2230), and MATS6c is a key descriptor. Further screened 5 compounds that have not yet been reported and have the potential to inhibit lipase activity (IC50pre ≤ 16.69 μM), these all bound to key residues (Tyr114 and Ser152) of pancreatic lipase, of which 3–4,1,5-carboxylic acid bound the most tightly (affinity of −9.8 kJ/mol). And the compounds-pancreatic lipase complexes (2-3-2-enoate) had good stability. The three compounds with high bioavailability have the potential to become novel pancreatic lipase inhibitors. This study provides a novel approach for the prediction of phenolic acids and their derivatives capable of inhibiting pancreatic lipase.

Interfacial adsorption behavior of the Aspergillus oryzae lipase-chitosan complex and stability evaluation of the resultant Pickering emulsion

To prompt the application of the chitosan (CS)-Aspergillus oryzae lipase (AOL) complex in the construction of novel biphasic catalysis medium, its Pickering emulsion stabilization ability as well as adsorption behavior in the oil-water interface were investigated and the stability of resultant emulsion was evaluated. The results indicated that the CS-AOL complex assembled in mass ratio 1:5 was an effective Pickering stabilizer and up to 90 % AOL could be retained in the emulsion interface. Quartz crystal microbalance with dissipation monitoring suggested that the CS-AOL complex spontaneously absorbed to oil-water interface; absorption dynamics analysis revealed that the adsorption was driven by diffusion accompanied by rapid structural rearrangement; while interfacial dilatational rheology demonstrated the formation of an elastic film in the oil-water interface. The Pickering emulsions were pseudoplastic and that in oil fraction 0.6 exhibited the elastic behavior in contrast to the viscous behavior in oil fractions 0.2 and 0.4. The Pickering emulsion exhibited excellent stability against storage for up to 28 d, pHs 2.0–12.0, heating at 25–90 °C, and up to 500 mmol/L NaCl, and the corresponding interfacial AOL retentions exceeded 80 % during exposure to these conditions. Hence, the CS-AOL complex could be used as a stabilizer to construct Pickering emulsion-based biphasic catalysis systems.

Childhood Hypertriglyceridemia: Is It Time for a New Approach?

Hypertriglyceridemia (HTG) is widely prevalent in youth. There is an unmet need for effective medications in the management of HTG in youth. The purpose of this review is to summarize the approach to HTG in acute and chronic settings, and highlight emerging therapies targeted at specific genes, proteins, and enzymes to selectively alter triglyceride (TG) metabolism. Genetic and lifestyle factors play a significant role in the pathophysiology of HTG. Severe elevation of TG poses a risk of acute pancreatitis, while mild-to-moderate HTG increases the risk for premature atherosclerotic cardiovascular disease (ASCVD) and, increasingly, has been linked with non-alcoholic fatty liver disease. Although a variety of therapeutic agents are in development, strict adherence to a heart healthy lifestyle, including dietary changes, remain the cornerstone of management for youth with HTG. In addition to lifestyle changes, pharmacological interventions, including fibrates, omega 3 fatty acids, and statins may be considered for management of moderate-to-severe HTG. In view of its association with premature cardiovascular disease (CVD), non-high-density-lipoprotein-C (non-HDL-C) is an important target for therapy in children with moderate HTG. Management of HTG is dependent on its etiology, concomitant symptoms, and degree of TG elevation. The last two decades have seen remarkable changes in drug development, specifically those that act through the lipoprotein lipase complex, including new targeted treatments such as inhibitors of apolipoprotein C3 and angiopoietin-like protein 3.

Fe2O3/Chitosan coated superparamagnetic nanoparticles supporting lipase enzyme from Candida Antarctica for microwave assisted biodiesel production

Biocatalysis has emerged as a green technology in chemical based catalysis. Immobilization of enzymes onto magnetized nanomaterials enhances downstream processing as it eases their separation from reaction mixture. Synthesis of the nanoparticles was performed in an aqueous solution of FeCl3.6H2O as precursor and NH3 as nucleating agent under microwave irradiation. The maghemite complex was cross-linked with glutaraldehyde to provide conducive environment for enzyme immobilization. Stability of produced immobilized lipases against different conditions were evaluated such as working temperatures from 27 °C to 85 °C and retained more than 64% of its activity at 85 °C. The immobilized lipase complex was able to withstand a wide range of acidic to alkaline environment from pH 5.5 to pH 9.5. The enzyme retains more than 59% of its activity after 14 days of storage and can be recycled for more than 7 cycles with remaining high activity at 93.7%. Developed enzyme was then subjected to microwave irradiation for transesterification of palm oil to produce biodiesel. Highest biodiesel recovery achieved from microwave assisted immobilized lipase catalysed transesterification of palm oil was 70.2%. The physical properties of produced biodiesel was evaluated and fulfilled the ASTM general requirement for fuels.

Physical and chemical study of coated Candida cylindracea with sorbitan esters

A new effective biocatalyst was prepared by coating lipase from Candida cylindracea with sorbitan esters such as span 60 and 65. This biocatalyst was characterized by employing the Scanning Electron Microscopy, X-Ray diffraction patterns and a lipase assay. The type of surfactant used during the lipase modification process has shown significant effect in the lipase activity and the protein content of the modified lipase complex. It was found that catalytic behavior of modified lipase was greatly affected by the source of the used span. Span 65-coated Candida cylindracea lipase showed the highest conversion of 50% in enzymatic esterification of glucose and lauric acid.

Camellia nitidissima Chi leaf as pancreatic lipase inhibitors: Inhibition potentials and mechanism.

In this study, Camellia nitidissima Chi leaf extract was investigated for its compounds and pancreatic lipase inhibitory potentials. The interaction was determined using ultraviolet (UV) spectroscopy, circular dichroism (CD), fluorescence spectroscopy (FS), and molecular docking to understand the inhibiton, kinetic, and conformation of extraction-pancreatic lipase complex. C. nitidissima Chi leaf extraction inhibited the pancreatic lipase activity in a dose-dependent manner at the concentration of 1-12mg/ml. The Lineweaver-Burk plots indicated that the inhibition on pancreatic lipase by extraction was noncompetitive. In addition, the decrease in α-helix contents, increase in β-sheet and β-turn, and decrease in fluorescence intensity after extraction treatment indicated that the conformation of pancreatic lipase was changed. This work revealed that C. nitidissima Chi leaf extraction played a significant role in inhibiting pancreatic lipase activity and brought out a solution of delay fat accumulation. PRACTICAL APPLICATIONS: This study reports the components in the extract of C. nitidissima Chi leaf and its inhibitory effect and mechanism of pancreatic lipase. C. nitidissima Chi leaf is a good source of bioactive components, including multiflorin B, kaempferol-3-O-rutinoside, vicenin-2, apigenin-6-C-pentosyl-8-C-hexosyl, vitexin, kaempferol, and other ingredients. It can inhibit pancreatic lipase and be used to control obesity and treat hyperlipidemia. This study also revealed the structure changes of C. nitidissima Chi leaf extract on pancreatic lipase, and further revealed the inhibitory mechanism of C. nitidissima Chi leaf extract on lipase, which provides a theoretical basis for C. nitidissima Chi leaf as a lipase inhibitor.

Synthesis, molecular modelling, in vitro and in vivo evaluation of conophylline inspired novel benzyloxy substituted indole glyoxylamides as potent pancreatic lipase inhibitors

Pancreatic lipase is a digestive enzyme involved in the hydrolysis of dietary fats. Orlistat, a potent pancreatic lipase inhibitor, is widely prescribed for long-term obesity treatment. Nevertheless, orlistat is reported for severe adverse effects including hepatotoxicity and pancreatitis. In the present study, a novel series of 11 benzyloxy substituted indole glyoxylamides were designed, synthesized and evaluated for in vitro pancreatic lipase inhibitory activity. Three analogues, 10b, 11b and 11c, exhibited potent activity (IC50 ≤ 2.5 µM), with 11b exhibiting a potent IC50 of 1.68 µM comparable to orlistat (IC50 = 0.99 µM). Further, 11b exhibited reversible competitive inhibition with an inhibitory constant value of 0.98 μM. Molecular docking of these analogues was in agreement with in vitro results, wherein the MolDock scores exhibited significant correlation with their inhibitory activity (Pearson’s r = 0.7122). A 50 ns molecular dynamics simulation of 11b-pancreatic lipase complex confirmed the role of extended alkyl interactions along with π-π stacking and π-cation interactions, in stabilizing the ligand (Maximum RMSD ≈ 3 Å) in the active site. Gastro-intestinal absorption and toxicity prediction of the three potent analogues highlighted the suitability of 11b for in vivo experiments. 11b at a dose of 20 mg/kg exhibited anti-obesity efficacy comparable to orlistat (10 mg/kg), wherein the serum triglycerides were found to be 94.95 and 83.85 mg/dL, respectively. Further, faecal triglyceride quantification indicated 11b to act through pancreatic lipase inhibition similar to orlistat. The present study identified a novel pancreatic lipase inhibitory benzyloxy substituted bis(indolyl) glyoxylamide 11b, with promising anti-obesity activity. Communicated by Ramaswamy H. Sarma

Mechanistic insights into the inhibition of pancreatic lipase by apigenin: Inhibitory interaction, conformational change and molecular docking studies

The inhibition of pancreatic lipase by apigenin, a natural dietary flavonoid, was investigated by various spectroscopic techniques and computational simulation. The results showed that apigenin reversibly inhibited pancreatic lipase activity in a competitive manner with an IC50 value of 0.45 ± 0.03 mM, and its combination with orlistat showed a synergistic effect. Formation of a complex between apigenin and pancreatic lipase driven by hydrogen bonds resulted in the fluorescence quenching of the enzyme through a static manner. The binding constant of apigenin with the enzyme was (5.47 ± 0.01) × 104 L mol−1 at 298 K, and the kinetic process of their interaction was characterized by the resolved concentration profiles and pure spectra of different components from the multivariate curve resolution-alternating least squares algorithm. The inhibition of pancreatic lipase by apigenin was mainly attributed to the tighter structure of the enzyme and the interaction between apigenin and the amino acid residues in the active center of the enzyme to prevent the substrate from being oxidized, as demonstrated by the analysis of circular dichroism spectra and molecular docking. Molecular dynamics simulation further characterized the binding conformation and property of apigenin-pancreatic lipase complex. This study provides novel insights into the mechanism of apigenin as pancreatic lipase inhibitor and the development of apigenin as an anti-obesity nutrient.

Dissociation of the G protein βγ from the Gq–PLCβ complex partially attenuates PIP2 hydrolysis

Phospholipase C β (PLCβ), which is activated by the Gq family of heterotrimeric G proteins, hydrolyzes the inner membrane lipid phosphatidylinositol 4,5-bisphosphate (PIP2), generating diacylglycerol and inositol 1,4,5-triphosphate (IP3). Because Gq and PLCβ regulate many crucial cellular processes and have been identified as major disease drivers, activation and termination of PLCβ signaling by the Gαq subunit have been extensively studied. Gq-coupled receptor activation induces intense and transient PIP2 hydrolysis, which subsequently recovers to a low-intensity steady-state equilibrium. However, the molecular underpinnings of this equilibrium remain unclear. Here, we explored the influence of signaling crosstalk between Gq and Gi/o pathways on PIP2 metabolism in living cells using single-cell and optogenetic approaches to spatially and temporally constrain signaling. Our data suggest that the Gβγ complex is a component of the highly efficient lipase GαqGTP–PLCβ–Gβγ. We found that over time, Gβγ dissociates from this lipase complex, leaving the less-efficient GαqGTP–PLCβ lipase complex and allowing the significant partial recovery of PIP2 levels. Our findings also indicate that the subtype of the Gγ subunit in Gβγ fine-tunes the lipase activity of Gq–PLCβ, in which cells expressing Gγ with higher plasma membrane interaction show lower PIP2 recovery. Given that Gγ shows cell- and tissue-specific subtype expression, our findings suggest the existence of tissue-specific distinct Gq–PLCβ signaling paradigms. Furthermore, these results also outline a molecular process that likely safeguards cells from excessive Gq signaling.

Crystal structure of pathogenic Staphylococcus aureus lipase complex with the anti-obesity drug orlistat

Staphylococcus aureus lipase (SAL), a triacylglycerol esterase, is an important virulence factor and may be a therapeutic target for infectious diseases. Herein, we determined the 3D structure of native SAL, the mutated S116A inactive form, and the inhibitor complex using the anti-obesity drug orlistat to aid in drug development. The determined crystal structures showed a typical α/β hydrolase motif with a dimeric form. Fatty acids bound near the active site in native SAL and inactive S116A mutant structures. We found that orlistat potently inhibits SAL activity, and it covalently bound to the catalytic Ser116 residue. This is the first report detailing orlistat–lipase binding. It provides structure-based information on the production of potent anti-SAL drugs and lipase inhibitors. These results also indicated that orlistat can be repositioned to treat bacterial diseases.

Spectroscopic and molecular docking studies on the binding mechanism of Mobic and lipase

Under simulated physiological conditions (pH=7.40), the interaction between non-steroidal anti-inflammatory drug mopicol and lipase was studied by fluorescence spectrum, ultraviolet absorption spectrum, circular dichroism spectrum and computer simulation technique. The experimental results showed that Mobic could quench the fluorescence of lipase by static quenching, and the binding site number is about 1. According to Forster's theory of non-radiation energy transfer, the binding distance between Mobic and lipase was obtained, r 0, indicating that hydrophobic force played a major role in the formation of Mobic and lipase complex. The results of synchronous fluorescence spectra, UV spectra and circular dichroism spectra showed that Mobic changed the conformation of lipase. The molecular docking results showed that the binding position of Mobic was close to the active center, indicating that Mobic could change the microenvironment of amino acid residues at the active center of lipase catalysis. The results of docking showed that there was hydrogen bond between Mobic and lipase, so the interaction between Mobic and lipase was driven by hydrophobic interaction and hydrogen bond.

A facile and robust non-natural three enzyme biocatalytic cascade based on Escherichia coli surface assembly for fatty alcohol production

Fatty alcohol is considered as a promising clean fuel alternative to fossil fuel. In this study, we developed a facile and robust multiple enzyme complex of lipase (LIP), carboxylic acid reductase (CAR) and aldehyde reductase (AHR) based on cohesin-dockerin specific interaction and E. coli-ice nucleation protein (INP) surface assembly for highly efficient conversion of triacylglycerols (TAGs) to fatty alcohols. The proximity effect, customized ratio and positional arrangement of the three enzymes were readily genetically generated. The optimized cell associated three enzyme complex gave 73% of conversion yield, and showed significantly improved stability in higher temperature, acidic/alkaline environments, polar organic solvents, high concentration of substrate, and good recyclability in successive biotransformations. The three enzyme complex provides an efficient non-natural synthetic cascade route for fatty alcohol bioproduction alternative to complex de novo biosynthesis route.

A genetically-encoded synthetic self-assembled multienzyme complex of lipase and P450 fatty acid decarboxylase for efficient bioproduction of fatty alkenes

We develop an efficient and economic cascade multienzymes for fatty alkene bioproduction based on the lipase hydrolysis coupled to the P450 decarboxylation in the form of multiple enzyme complex. One step preparation of a multienzyme complex was based on a mixture of cell extracts including dockerin-enzyme fusions and one cohesin-cellulose binding module (CBM) fusion through high specific interaction of dockerin and cohesin. Simultaneously, the CBM was bound to cellulose carrier to form co-immobilized multienzyme. The key factors affecting overall efficiency of alkene bioproduction including substrate channeling of hydrolysis and decarboxylation, the ratio and position of two enzymes, stability were all addressed by genetically engineering of the synthetic CBM-cohesin fusions. The multienzymes exhibited more than 9.2 fold enhancement in initial reaction rate and much higher conversion yields (69%–72%) compared to mixture of free enzyme counterpart. The enzymatic cascade based multienzymes could efficiently convert renewable triglycerides to alkenes.

Molecular basis of the familial chylomicronemia syndrome in patients from the National Dyslipidemia Registry of the Spanish Atherosclerosis Society

Familial chylomicronemia syndrome (FCS) is an extremely rare lipoprotein disorder caused by mutations in at least 5 genes of the lipoprotein lipase (LPL) complex. This work shows the molecular analysis of patients diagnosed with FCS, who attended the Spanish Arteriosclerosis Society lipid units and were included in the National Dyslipidemia Registry. Among the 238 patients registered with severe hypertriglyceridemia (fasting triglycerides>1000mg/dL), 26 were diagnosed with FCS as they had confirmed postheparin plasma LPL activity deficiency and/or homozygosity for loss-of-function mutations in LPL, GPIHBP1, APOC2, LMF1, or Apolipoprotein A5 (APOA5). Among the 26 FCS cases, 23 had mutations in the homozygous state: 19 in LPL and 4 in the GPIHBP1 gene. The molecular analysis revealed 3 novel mutations: 2 in LPL, in 2 unrelated patients (c.312delA; p.Asp105Thrfs*66 and c.629A>G; p.His210Arg), and 1 in GPHIBP1 in a third patient (c.502delC; p.Leu168Serfs*83). These 3 patients had confirmed lack of LPL activity. Three additional patients with confirmed LPL activity deficiency were heterozygous carriers of mutations in the genes analyzed. Among these, we found 2 novel mutations in APOA5 (c.50-1G>A and c.326_327insC; p.Tyr110Leufs*158). We have identified 5 novel pathogenic mutations: 2 in LPL, 1 in GPIHBP1, and 2 in the APOA5 gene. The genetic defaults accounting for the LPL activity deficiency of 23 of them have been clearly identified and 3 patients, who harbored mutations in heterozygosity, were diagnosed based on LPL activity deficiency, which raises the question of the involvement of new genes in the manifestation of FCS.

Enzyme-immobilized clay nanotube-chitosan membranes with sustainable biocatalytic activities.

We have developed a simple and effective strategy to prepare an enzymatic membrane by the admixing of a halloysite clay nanotube-lipase complex and a chitosan solution. The loading of 3 wt% lipase into the lumen of halloysite clay nanotubes was enhanced with an electrostatic interaction. 10 wt% of lipase-nanotubes were dispersed in an aqueous chitosan solution and cast as a coating. The enzymatic chitosan-halloysite membranes displayed increased pH, temperature stability and long-term usability for the catalytic decomposition of lipids: 90% of the initial activity was preserved at 80 °C, 70% of the functionality remained at the high pH of 9, and 85% of the activity was sustained after ten continuous cycles of use. The placement of the second antimicrobial enzyme-lysozyme at the outer surface of the clay nanotubes allowed for a synergistic increase in the activity of the composite antibacterial formulation. The lipase/lysozyme-co-immobilized clay nanotube-chitosan membranes are promising in anti-biofouling applications.

A surfactant-coated lipase immobilized in magnetic nanoparticles for multicycle ethyl isovalerate enzymatic production

Gum arabic coated magnetic Fe3O4 nanoparticles (GAMNP) were prepared by chemical co-precipitation method and their surface morphology, particle size and presence of polymer-coating was confirmed by various measurements, including transmission electron microscopy (TEM), X-ray diffraction (XRD), thermo gravimetric analysis (TGA), and Fourier transform infra red (FTIR) analysis. Magnetic particles were employed for their potential application as a support material for lipase immobilization. Glutaraldehyde was used as a coupling agent for efficient binding of lipase onto the magnetic carrier. For this purpose, the surface of a Candida rugosa lipase was initially coated with various surfactants, to stabilize enzyme in its open form, and then immobilized on to the support. This immobilized system was used as a biocatalyst for ethyl isovalerate, a flavor ester, production. The influence of various factors such as type of surfactant, optimum temperature and pH requirement, organic solvent used, amount of surfactant in coating lipase and effect of enzyme loadings on the esterification reaction were systematically studied. Different surfactants were used amongst which non-ionic surfactant performed better, showing about 80% esterification yield in 48h as compared to cationic/anionic surfactants. Enhanced activity due to interfacial activation was observed for immobilized non-ionic surfactant–lipase complex. The immobilized surfactant coated lipase activity was retained after reusing seven times.

Crystallization and preliminary X-ray diffraction studies of a complex of extracellular lipase fromStreptomyces rimosuswith the inhibitor 3,4-dichloroisocoumarin

A recombinant lipase (triacylglycerol acylhydrolase; EC 3.1.1.3) from the bacterium Streptomyces rimosus was inhibited by the serine protease inhibitor 3,4-dichloroisocoumarin and crystallized by the hanging-drop vapour-diffusion method at 291 K. The crystals belonged to the monoclinic space group P2(1), with unit-cell parameters a = 38.1, b = 78.7, c = 56.6 Å, β = 104.5° and probably two molecules in the asymmetric unit. Diffraction data were collected to 1.7 Å resolution using synchrotron radiation on the XRD beamline of the Elettra synchrotron, Trieste, Italy.