• Journal of Microbiology and Biotechnology
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• v.10 no.5
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• pp.721-723
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• 2000

The phospholipase $A_2$-catalyzed transesterification of phosphatidylcholine (PC, 95%) with nervonic acid (NA, 95%) was successfully carried out in an organic solvent. The maximum yield after 48 h was 10.3% (w/w) at $50^{\circ}C$ with an initial water activity ($a_w$) of 0.16, and a molar ratio of NA to PC of 20 in 5 ml ethyl acetate.

• Journal of Life Science
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• v.24 no.12
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• pp.1378-1382
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• 2014

Phospholipase D (PLD) catalyzes the hydrolysis of phospholipid to phosphatidic acid (PA), a lipid secondary messenger. Two forms of PLD isozymes, phosphatidylcholine-specific PLD1 and PLD2, have been identified. PLD has emerged as a critical regulator of cell proliferation and survival signaling, and dysregulation of PLD occurs in a various illnesses, including cancer. PLD activity is essential for cell survival and protection from apoptosis. Overexpression of PLD isozymes or PLD-generated PA attenuates the expression of apoptotic genes and confers resistance to apoptosis. The apoptosis-related molecular mechanisms of PLD remain largely unknown. Recently, the dynamics of PLD turnover during apoptosis have been reported. The cleavage of PLD isozymes as specific substrates of caspase differentially regulates apoptosis. PLD1 is cleaved at one internal site, and PLD2 is cleaved two sites at the front of the N-terminus. The cleavage of PLD1 reduces its enzymatic activity, probably via the dissociation of two catalytic motifs, whereas the cleavage of PLD2 does not affect the catalytic motifs and its activity. Thus, PLD2 maintains antiapoptotic capacity, despite its cleavage. Therefore, the differential cleavage pattern of PLD isozymes by caspase affects its enzymatic activity and antiapoptotic function. Thus, PLD is considered a potential target for cancer therapy. We summarize recent studies regarding the functional role of PLD in apoptosis.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1995.04a
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• pp.58-58
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• 1995

식물에서부터 새로운 소염작용제를 개발하기 위하여 여러식물을 대상으로 염증반응의 초기단계에서 중요한 역할을 하는 것으로 알려진 Phospholipase $A_2$에 저해활성을 갖는 물질을 검색하였고 그 중 강한 억제활성을 보인 유근피에서 유효성분을 분리하였다. 유근피의 에칠 아세테이트 분획에 대하여 실리카겔 크로마토그래피, Sephadex LH-20 크로마토그래피, 분취 박막 크로마토그래피를 수행하여 phenol성 -OH기를 갖는 활성성분인 PSH-II-84-1를 분리하였다. $^1$H-NMR 신호의 양상과 짝지움 상수 값에서 분리된 물질은 (+)-catechin 의 당 유도체로 확인되었다. $^{13}$C-NMR 자료를 분석하여 치환된 당은 D-apiofuranose로 확인되었다. 방향족환의 $^{l3}$C-NMR 신호들은 extended Huekel theory를 응용하여 얻은 net charge 계산 값과 상관시켜 할당하였다. 이상의 구조연구 결과 이 물질은 (+)-catechin-7-0-$\beta$-D-apiofuranoside로 밝혀졌다. (+)-catechin-7-0-$\beta$-D-apiofuranoside의 효소억제활성은 Type II Phospholipase $A_2$에 대하여 $IC_{50}$/이 600$\mu$M이었다.다.

• YAKHAK HOEJI
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• v.46 no.3
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• pp.192-196
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• 2002

To investigate the effect of intravenous ethanol administration on pancreatic exocrine secretion, we measured volume and protein amount in pancreatic juice and assayed amylase activity and phospholipase $A_2$ activity in pancreatic fragments and serum. Acute pancreatitis induced by obstruction of common bile-pancreatic duct (CBPD) and caerulein infusion (5 $\mu\textrm{g}$/kg/hr) showed typical characteristics, such as hyperamylasemia and pancreatic edema and increase of phospholipase $A_2$ activity in pancreatic fragments and serum. Intravenous ethanol infusion (50 mg/kg/hr) significantly stimulated pancreatic exocrine secretion, but such a stimulatory effect of ethanol disappeared at dose of 100 mg/kg/hr without typical symptoms of acute pancreatitis. In microscopic examination, there were no typical changes of edematous pancreatitis in ethanol administrated rats. These results suggest that acute ethanol administration has dual effect on exocrine pancreatic secretion: low dose of ethanol (50 mg/kg/hr) stimulates pancreatic exocrine secretion, whereas high dose of ethanol (100 mg/kg/hr) does not without typical changes of edematous pancreatitis.

• Journal of Physiology & Pathology in Korean Medicine
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• v.18 no.5
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• pp.1322-1330
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• 2004

This experimental studies were performed in order to prove the effect of Phospholipase A₂(PLA₂) Herbal-acupuncture by using rats that had neuronal damage due to the Middle Cerebral Artery Occulsion(MCAO). We observed the change of extracellular concentrations(μM) Of dopamine, DOPAC, HVA, HIAA, glutamate, aspartate, GABA, glysine, taurine, alanine, and tyrosine as extracted by vivo microdialysis, in the PLA₂ Herbal-acupuncture administrated rats(240-260g, Sprague-Dawley) subjected to the MCAO. The dialysates were extracted three times before the MCAO and six times after the MCAO every 20 minutes, and ana lysed by highperformance liquid chromatography(HPLC). PLA₂ Herbal-acupuncture significantly inhibited glutamate and tyrosine which are stimulant neurotransmitters at brain ischemia, and it significantly decreased glycine, GABA, taurine, and alanine which are inhibitory neurotransmitters at brain ischemia. PLA₂ Herbal-acupuncture may prevent delayed neuronal death(DND) in selectively vulnerable focal areas of the brain effectively.

• Journal of Microbiology and Biotechnology
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• v.6 no.6
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• pp.407-413
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• 1996

A novel type of extracellular phospholipase $A_1$ was isolated from Serratia sp. MK1 and purified to homogeneity by ammonium sulfate precipitation, anion exchange and gel filtration chromatography. The purified enzyme was a monomer with a molecular mass of about 43, 000 Da. This enzyme showed the highest lipolytic activity toward phosphatidylserine among the phosphoglycerides tested, and preferentially catalyzed the hydrolysis of the ester bond in phosphatidic acid to lyso-phosphatidic acid. Enzyme activity was completely inhibited by the addition of a chelating agent such as EDTA, and inhibited enzyme activity was fully recovered by the presence of $Ca^{2+}$. This implies that the enzyme requires $Ca^{2+}$ for activity. The enzyme was stable up to $70^{\circ}C$ when incubated for 1 h at pH 8.5, and the optimal pH and temperature were 8.5 and $50^{\circ}C$, respectively.

• The Korean Journal of Physiology and Pharmacology
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• v.14 no.3
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• pp.163-167
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• 2010

This study investigated the effects of the methanol extracts of Morinda citrifolia containing numerous anthraquinone and iridoid on phospholipase $A_2$ ($PLA_2$) isozyme. $PLA_2$ activity was measured using various $PLA_2$ substrates, including 10-pyrene phosphatidylcholine, 1-palmitoyl-2-[$^{14}C$]arachidonyl phosphatidylcholine ([$^{14}C$]AA-PC), and [$^3H$]arachidonic acid (AA). The methanol extracts suppressed melittin-induced [$_3H$]AA release in a concentration-dependent manner in RAW 264.7 cells, and inhibited $cPLA_2/sPLA_2$-induced hydrolysis of [$^{14}C$]AA-PC in a concentration- and time-dependent manner. A Dixon plot showed that the inhibition by methanol extracts on $cPLA_2$ and $sPLA_2$ appeared to be competitive with inhibition constants ($K_i$) of $3.7{\mu}g/ml$ and $12.6{\mu}g/ml$, respectively. These data suggest that methanol extracts of Morinda citrifolia inhibits both $Ca^{2+}$-dependent $PLA_2$ such as, $cPLA_2$ and $sPLA_2$. Therefore, Morinda citrifolia may possess anti-inflammatory activity secondary to $Ca^{2+}$-dependent $PLA_2$ inhibition.

• The Korean Journal of Physiology and Pharmacology
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• v.2 no.4
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• pp.411-417
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• 1998

The role of phospholipase ($A_2\;PLA_2$) in tumor cell growth was investigated using SK-N-MC human neuroblastoma cells. 4-Bromophenacyl bromide (BPB) and mepacrine (Mep), known $PLA_2$ inhibitors, suppressed growth of the tumor cells in a dose-dependent manner without a significant cytotoxicity. Melittin (Mel), a $PLA_2$ activator, enhanced the cell growth in a concentration-dependent fashion. The growth-enhancing effects of Mel were significantly reversed by the co-treatment with $PLA_2$ inhibitors. In addition, Mel induced intracellular $Ca^{2+}$ release from internal stores like as did serum, a known intracellular $Ca^{2+}$ agonist in the tumor cells. Intracellular $Ca^{2+}$ release induced by these agonists was significantly blocked by $PLA_2$ inhibitors at growth-inhibitory concentrations. Arachidonic acid (AA), a product of the $PLA_2-catalyzed$ reaction, induced cell growth enhancement and intracellular $Ca^{2+}$ release. These effects of AA were significantly blocked by BAPTA/AM, an intracellular $Ca^{2+}$ chelator. Taken together, these results suggest that the modulation of $PLA_2$ activity may be one of the regulatory mechanisms of cell growth in human neuroblastoma cells. Intracellular $Ca^{2+}$ may act as a key mediator in the $PLA_2-induced$ growth regulation.

• Korean journal of applied entomology
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• v.51 no.3
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• pp.299-303
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• 2012

This study aims to investigate whether geographical variation affects the antibacterial component properties of honeybee (Apis mellifera L.) venom in Korea. Honeybee venom samples were collected from May to September, during 2010 and 2011, from 35 different sites, and were analyzed for major components, including melittin, apamin and phospholipase A2 were determined by a liquid chromatography using ammonium formate, acetonitrile, trifluoracetic acid. On average, melittin, apamin and phospholipase A2 were determined $55.2{\pm}2.07%$, $22.57{\pm}0.103%$, and $12.51{\pm}0.37%$, respectively. The ratio of the major components, including melittin, apamin and phospholipase A2 did not differ significantly according to flower or temperature during collections (One way-ANOVA, Duncan's test (${\alpha}$=0.05)).

• YAKHAK HOEJI
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• v.41 no.5
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• pp.565-570
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• 1997

High levels of extracellular phospholipase $A_2$ (Plase $A_2$) associated with inflammatory process in man and animal models have been extensively reported elsew here. Thus, a logical approach to the treatment of inflammatory diseases should involve the inhibitors of Plase $A_2$. To develop new Plase $A_2$ inhibitors from natural products, two hundred crude drugs were screened using group II PLA$A_2$ inhibitory activity. Among them, methanol extract of 5 medicinal plants such as, Raphani Semen, Moutan cortex radicis, Arecae semen, Caryophylli Cortex and Betulae Cortex inhibited more than 90% of PLase $A_2$ activity at a concentration 2.5${\mu}g/ml$. Then, 10 methanol extracts sample were transferred into organic solvents, PLase $A_2$ inhibitory effects were found mainly in CHCl3 and EtoAc fractions.