• YAKHAK HOEJI
• /
• v.45 no.4
• /
• pp.413-418
• /
• 2001

To investigate action of ATP on ischemia-induced brain injury, we measured phospholipase $A_2$activity and nitric oxide (NO) production in C6 cells. ATP alone did not have any influence on phospholipase $A_2$activity but increased NO production. Glutamate (1 mM) significantly increased phospholipase $A_2$activity whereas did not increased NO production. ATP significantly inhibited phospholipase $A_2$activation induced by 0.1 $\mu$M A23187, 1 mM glutamate and 1 mM $H_2O$$_2$, but did not inhibited 1 $\mu$M PMA-induced phospholipase $A_2$activation. From the above results, it is suggested that the action of ATP in C6 cells has dual actions, such as the inhibition of agonist-induced phospholipase $A_2$activation and the increase of NO production.

• Journal of Pharmacopuncture
• /
• v.4 no.2
• /
• pp.5-15
• /
• 2001

This study was carried out for production of neutral antibody to bee venom $(anti-phospholipase\;A_2IgY)$. Hen layings were injected repeatedly with bee venom and phospholipase $A_2$ with Freund's adjuvant. Specific antibody in egg yolk from immunized hen laying was separated, and purified, also immunological characteristics of anti phospholipase $A_2\;IgY$ was invested. The results were summarized as follows: 1. Phospholipase $A_2$ was showed single band at molecular weight 17,000 in SDS-PAGE and bee venom was showed two band at molecular weight 17,000 and under molecular weight 6,500 in SDS-PAGE. 2. During 70 days after hen immunized with bee venom and phospholipase $A_2$, antibodies(anti-bee venom IgY) to bee venom were showed poor ELISA value in egg yolk, but antibodies$(anti-Phospholipase\;A_2IgY)$ to phospholipase $A_2$ in egg yolk were increased ELISA value from 8 days or 15 days and found maximum ELISA value at 42 days. Also after booster at 49 days, ELISA value of anti Phospholipase $A_2\;IgY$ in egg yolk was supported at optical density(O.D) 1.0 level, continuously. 3. Titer of phospholipase $A_2\;IgY$ was showed 1: 32,000. 4. In double immunodiffusion test to phospholipase $A_2$ after double dilution of anti-phospholipase $A_2\;IgY$, only precipitation line was made in 1:1 dilution well of anti-Phospholipase $A_2\;IgY$. But In immunodiffusion test to anti-phospholipase $A_2\;IgY$ after double dilution of phospholipase $A_2$, Precipitation line to 250ul/ml well of phospholipase $A_2$ was showed. In double immunodiffusion test to bee venom(1mg/ml) after double dilution anti-phospholipase $A_2\;IgY$, all well without 1:32 dilution well were showed strong precipitation line. 5. In dot bloting test to anti-phospholipase $A_2\;IgY$ after diluting bee venom(0.5mg/ml), dot bloting color was showed clearly to $1/100(5{\mu}g/ml)$ in bee venom.

• YAKHAK HOEJI
• /
• v.41 no.2
• /
• pp.212-219
• /
• 1997

Multiple forms of extracellular phospholipase $A_2$ have been detected in human amniotic fluid (HAF). When HAF was subjected to heparin-Sepharose column chromatography, phospholipase $A_2$ activity was detected in both heparin-non binding and binding fraction. The activity of heparin-non binding fraction was further purified by sequential uses of column chromatographies on butyl-Toy-opearl 650M and DEAE-Sephacel. DEAE-Sephacel fraction contained three different phospholipase $A_2$ activities (Peak I, II, III). The molecular weight of DEAE-Sephacel fraction phospholipase $A_2$ determined by SDS-PAGE were about 52KDa (Peak I). Peak II, III required micromolar $Ca^{2+}$ ion for its maximum activity, but Peak I enzyme showed calcium independent phospholipase $A_2$ activity and showed broad range of pH (6.0~10.0) optimum. All these enzymes were not recognized by a monoclonal antibody raised against phospholipase $A_2$ from human synovial fluid. These results suggest that HAF might contain multiple forms of extracellular phospholipase $A_2$, which may neither belong to the 14KDa group II phospholipase $A_2$ family nor cytosolic phospholipase $A_2$.

• Natural Product Sciences
• /
• v.26 no.4
• /
• pp.259-267
• /
• 2020

Snakebite is a severe medical, economic, and social problem across the world, mostly in the tropical and subtropical area. These regions of the globe have typical of the world's venomous snakes present where access to prompt treatment is limited or not available. Snake venom is a complex mixture of toxin proteins like neurotoxin and cardiotoxin, and other enzymes like phospholipase A2 (PLA2), haemorrhaging, transaminase, hyaluronidase, phosphodiesterase, acetylcholinesterase, cytolytic and necrotic toxins. Snake venom shows a wide range of biological effects like anticoagulation or platelet aggregation, hemolysis, hypotension and edema. Phospholipase A2 is the principal constituent of snake venom; it catalyzes the hydrolysis of the sn-2 position of membrane glycerophospholipids to liberate arachidonic acid, which is the precursor of eicosanoids including prostaglandins and leukotrienes. The information regarding the structure and function of the phospholipase A2 enzyme may help in treating the snakebite victims. This review article constitutes a brief description of the structure, types, mechanism occurrence, and tests of phospholipase A2 and role of components of medicinal plants used to inhibit phospholipase A2.

• Korean Journal of Food Science and Technology
• /
• v.29 no.1
• /
• pp.26-31
• /
• 1997

Bee venom (Apis mellifera) phospholipase $A_2$ solubilized in reversed micelles containing small amount of water stabilized by surfactant could catalyze the hydrolysis of dipalmitoyl phosphatidylcholine (DPPC). A sensitive and simple high performance liquid chromatographic (HPLC) methodology of phospholipase $A_2$ assay for the hydrolysis of DPPC was developed. Kinetic analysis of the phospholipase $A_2$-catalyzed reaction was found to be possible in reversed micelles. Among the surfactants and organic solvents tested, aerosol-OT and isooctane were most effective for the hydrolysis of DPPC in reversed micelles. Optimal temperature, optimal pH, $K_{m,app.},\;V_{max.,app.}$ and activation energy were determined to be $35{\sim}40^{\circ}C$, 7.0, 8.73 mM, 2.83 units/㎎ protein and 12.31 kcal/mole, respectively. The hydrolysis activity was dependent on water content and maximum activity was obtained at R value (=[water]/[aerosol-OT]) of 10.0.

• YAKHAK HOEJI
• /
• v.45 no.3
• /
• pp.287-292
• /
• 2001

To investigate whether phospholipase $A_2$pathway is involved in histamine release of rat peritoneal mast cells, we measured histamine release in the presence of various enzyme inhibitors involved in eicosanoid pathway, such as phospholipase $A_2$, cyclooxygenase and lipoxygenase. Phospholipase $A_2$inhibitors, manoalide and OPC, significantly inhibited histamine release induced by 100 $\mu$M ATP and 1$\mu$g/ml compound 48/80. Cyclooxygenase inhibitors, ibuprofen and indomethacin, significantly inhibited ATP-induced histamine release and lipoxygenase inhibitors, baicalein and caffeic acid, also significantly inhibited. To investigate the involvement of protein kinase in ATP- and compound 48/80-induced histamine release, we observed effects of protein kinase inhibitors on histamine release. Bisindolmaleimide (protein kinase C antagonist) dose-dependently inhibited both ATP and compound 48/80-induced histamine release. Tyrosine kinase inhibitors (methyl 2,5-dihydroxy cinnamate and genistein) dose-dependently inhibited ATP and compound 48/80-induced histamine release. Protein kinase C and tyrosine kinase seem to be involved in histamine release induced by ATP and compound 48/80. These results suggest that phospholipase $A_2$pathway as well as protein kinase C and tyrosine kinase are involved in histamine release of rat peritoneal mast cells by ATP and compound 48/80.

• Parasites, Hosts and Diseases
• /
• v.49 no.1
• /
• pp.1-8
• /
• 2011

The pathogenesis and pathophysiology of Acanthamoeba infections remain incompletely understood. Phospholipases are known to cleave phospholipids, suggesting their possible involvement in the host cell plasma membrane disruption leading to host cell penetration and lysis. The aims of the present study were to determine phospholipase activities in Acanthamoeba and to determine their roles in the pathogenesis of Acanthamoeba. Using an encephalitis isolate (T1 genotype), a keratitis isolate (T4 genotype), and an environmental isolate (T7 genotype), we demonstrated that Acanthamoeba exhibited phospholipase $A_2$ (PLA$_2$). and phospholipase D (PLD) activities in a spectrophotometry-based assay. Interestingly, the encephalitis isolates of Acanthamoeba exhibited higher phospholipase activities as compared with the keratitis isolates, but the environmental isolates exhibited the highest phospholipase activities. Moreover, Acanthamoeba isolates exhibited higher PLD activities compared with the PLA$_2$. Acanthamoeba exhibited optimal phospholipase activities at $37^{\circ}C$ and at neutral pH indicating their physiological relevance. The functional role of phospholipases was determined by in vitro assays using human brain microvascular endothelial cells (HBMEC), which constitute the blood-brain barrier. We observed that a PLD-specific inhibitor, i.e., compound 48/80, partially inhibited Acanthamoeba encephalitis isolate cytotoxicity of the host cells, while PLA$_2$-specific inhibitor, i.e., cytidine 5'-diphosphocholine, had no effect on parasite-mediated HBMEC cytotoxicity. Overall, the T7 exhibited higher phospholipase activities as compared to the T4. In contract, the T7 exhibited minimal binding to, or cytotoxicity of, HBMEC.

• Journal of the Korean Chemical Society
• /
• v.52 no.5
• /
• pp.488-494
• /
• 2008

• The Korean Journal of Pharmacology
• /
• v.27 no.2
• /
• pp.191-196
• /
• 1991

The present study was performed to determine whether estradiol, via cAMP mediation, induces prostaglandin synthesis by modulating phospholipase $A_2$ activity which hydrolyzes phospholipids into arachidonic acids, a precursor for prostaglandin synthesis, during the implantation process in rats. Uterine phospholipase $A_2$ activity was elevated on day 5 of pregnancy when implantation normally occurs in rats. Moreover, phospholipase $A_2$ activity was higher in the implant sites than in the non-implant sites of uterus on day 6. In delayed implantation model, phospholipase $A_2$ activity was increased at 12 hrs after estradiol administration and at 8 hrs after dbcAMP administration. In addition, higher activity of phospholipase $A_2$ was induced by the treatment of estradiol plus theophylline, compared with estradiol-only treated group. The simultaneous treatment of indomethacin with estradiol or dbcAMP did not alter phospholipase $A_2$ activity compared with estradiol or dbcAMP-only treated group although significant suppression was observed in uterine PGE and $PGF_{2{\alpha}}$ concentrations. These results suggest that estradiol or cAMP stimulates uterine phospholipase $A_2$ activity, thereby increasing prostaglandin synthesis during the implantation process in rats.

• BMB Reports
• /
• v.30 no.2
• /
• pp.101-105
• /
• 1997

Extracellular phospholipase $A_2$ activity has been detected in urine of patients with acute pyelonephritis (APN). This enzyme required micromolar $Ca^{2+}$ ion for its maximum activity and showed a broad range of pH (4.5~10) optimum. Urine enzyme hydrolyzed phosphatidylethanolamine (PE) and phosphatidylserine (PS) more effectively than phosphatidylcholine (PC). $PLA_2$ activity in the urine of patients with APN was about 5-fold higher than that of healthy individuals. When urine was subjected to heparinSepharose column chromatography, phospholipase $A_2$ activity was detected in both heparin-non-binding and binding fractions. Both phospholipase $A_2$ activities were sensitive less than a micromolar calcium concentration and did not react with anti-human 14-kDa group II phospholipase $A_2$ monoclonal antibody, HP-l. These findings suggest that two kinds of novel extracellular phospholipase $A_2$. which may not belong to the 14-kDa group II phospholipase $A_2$ family, exist in the urine of patients with APN.