• 대한약리학회지
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• 제27권2호
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• pp.191-196
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• 1991

본 연구에서는 흰쥐의 수정란 착상시기에 estradiol이 prostaglandins(PGs) 합성의 전구체인 arachidonic acid를 생성하는데 관여하는 phospholipase $A_2(PLA_2)$의 활성도를 조절하므로써 PGs의 합성을 촉진하는가를 조사하여 다음과 같은 결과를 얻었다. 자궁의 $PLA_2$ 활성도는 수정란이 착상하는 시기인 임신 제 5일에 증가되었으며, 비착상부위에서보다는 착상부위에서 더 높은 것으로 나타났다. Delayed implantation model에서, $PLA_2$ 활성도는 estradiol을 투여한 지 11시간후에 증가되었으며, dbcAMP를 투여한지 8시간후에 증가되었다. 또한 estradiol을 투여하기 2시간전에 phosphodiesterase inhibitor인 theophylline을 투여하면 estradiol만 투여한것에 비하여 $PLA_2$ 활성도가 증가되었다. Estradiol 또는 dbcAMP와 함께 indomethacin을 투여하면 자궁의 PGs합성은 억제되었으나 $PLA_2$ 활성도에는 영향을 주지않았다. 이상의 결과로 보아 흰쥐의 착상시기에 estradiol은 cAMP를 매개로하여 자궁의 $PLA_2$ 활성도를 촉진하므로써 PGs의 합성을 증가시키는 것으로 생각된다.

• The Korean Journal of Physiology and Pharmacology
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• 제2권2호
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• pp.251-260
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• 1998

Cromakalim (BRL 34915), known as an airway smooth muscle relaxant, inhibited the releases of mediators in the antigen-induced mast cell activation. It has been suggested that cromakalim, in part, inhibited mediator releases by inhibiting the initial increase of 1,2-diacylglycerol (DAG) produced by the activation of the other phospholipase system which is different from phosphatidylcholine-phospholipase D pathway. The aim of this study is to further examine the inhibitory mechanism of cromakalim on the mediator release in the mast cell activation. Guinea pig lung mast cells were purified by using enzyme digestion and percoll density gradient. In purified mast cells prelabeled with $[^3H]PIP_2$, phospholipase C (PLC) activity was assessed by the production of $[^3H]$insitol phosphates. Protein kinase C (PKC) activity was assessed by measuring the protein phosphorylated from mast cells prelabeled with $[{\gamma}-32P]ATP$, and Phospholipase $A_2\;(PLA_2)$ activity by measuring the lyso-phosphatidylcholine produced from mast cell prelabeled with 1-palmitoyl-2-arachidonyl $phosphatidyl-[^{14}C]choline$. Histamine was assayed by fluorometric analyzer, and leukotrienes by radioimmunoassay. The PLC activity was increased by activation of the passively sensitized mast cells. This increased PLC activity was decreased by cromakalim pretreatment. The PKC activity increased by the activation of the passively sensitized mast cells was decreased by calphostin C, staurosporine and cromakalim, respectively. The $PLA_2$ activity was increased in the activated mast cells. The pretreatment of cromakalim did not significantly decrease $PLA_2$ activity. These data show that cromakalim inhibits histamine release by continuously inhibiting signal transduction processes which is mediated via PLC pathway during mast cell activation, but that cromakalim does not affect $PLA_2$ activity related to leukotriene release.

• 한국식품과학회지
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• 제29권1호
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• pp.26-31
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• 1997

물을 극미량 함유하는 미수계 효소반응계인 aerosol-OT/이소옥탄으로 구성된 역미셀계내에서 레시친의 일종인 DPPC (dipalmitoyl phosphatidylcholine)의 가수분해반응을 phospholipase $A_2$가 촉매할 수 있었다. 또한 phospholipase $A_2$에 의한 가수분해반응을 정량분석하기 위한 고성능 액체 크로마토그래피에 의한 예민하고 간편한 방법을 고안하였는 바, 이에 의하여 aerosol-OT/이소옥탄 역미셀계내에서 phospholipase $A_2$에 의한 가수분해반응의 동력학적인 분석이 가능하였다. 한편, 여러가지 유화제와 유기용매 중 aerosol-OT와 이소옥탄일 때 효소반응이 가장 효과적이었으며, 반응 적정온도는 $35{\sim}40^{\circ}C$, 적정 pH는 7.0이었다. 또한 역미셀계내에서의 가수분해반응은 수분 함량변화에 민감하였으며, R-값(=[water]/[aerosol-OT])이 10.0일 때 가장 높은 효소활성을 나타내었다. 효소반응을 위한 최적조건하에서의 $K_{m,app.}$ 및 $V_{max.,app.}$는 각각 8.73 mM, 2.83 units/㎎ protein이었으며, 역미셀계내에서 phospholipase $A_2$에 의한 DPPC가수분해반응의 활성화에너지는 12.31 kcal/mole로 산출되었다.

• Natural Product Sciences
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• 제7권1호
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• pp.17-20
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• 2001

The activity of the lipase and phospholipase extracted from the seed meal of Nicotiana tabacum L. was studied with the help of Spectrophotometer at different pH, Temperatures and Solvents. Both lipase and phospholipase shown optimum activity at pH 6 and $45^{\circ}C$. Their activities also maximize when n-heptane was used as solvent media.

• The Korean Journal of Physiology and Pharmacology
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• 제14권6호
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• pp.427-433
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• 2010

This study was conducted to investigate the effects of extremely low frequency electromagnetic fields (EMF) on signal pathway in plasma membrane of cultured cells (RAW 264.7 cells and RBL 2H3 cells), by measuring the activity of phospholipase $A_2$ ($PLA_2$), phospholipase C (PLC) and phospholipase D (PLD). The cells were exposed to the EMF (60 Hz, 0.1 or 1 mT) for 4 or 16 h. The basal and $0.5\;{\mu}M$ melittin-induced arachidonic acid release was not affected by EMF in both cells. In cell-free $PLA_2$ assay, we failed to observe tbe change of $cPLA_2$ and $sPLA_2$ activity. Also both PLC and PLD activities did not show any change in the two cell lines exposed to EMF. This study suggests that the exposure condition of EMF (60 Hz, 0.1 or 1 mT) which is 2.4 fold higher than the limit of occupational exposure does not induce phospholipases-associated signal pathway in RAW 264.7 cells and RBL 2H3 cells.

• Molecules and Cells
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• 제26권5호
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• pp.481-485
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• 2008

As an inhibitor of phosphatidylcholine-specific phospholipase C (PC-PLC), D609 has been widely used to explain the role of PC-PLC in various signal transduction pathways. This study shows that D609 inhibits group IV cytosolic phospholipase $A_2$ ($cPLA_2$), but neither secretory $PLA_2$ nor a $Ca^{2+}$-dependent $PLA_2$. Dixon plot analysis shows a mixed pattern of noncompetitive and uncompetitive inhibition with $K_i=86.25{\mu}M$ for the $cPLA_2$ purified from bovine spleen. D609 also time- and dose-dependently reduces the release of arachidonic acid from a $Ca^{2+}$- ionophore A23187-stimulated MDCK cells. In the AA release experiment, $IC_{50}$ of D609 was ${\sim375}{\mu}M$, suggesting that this reagent may not enter the cells easily. The present study indicates that the inhibitory effects of D609 on various cellular responses may be partially attributable to the inhibition of $cPLA_2$.

• Natural Product Sciences
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• 제10권6호
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• pp.302-305
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• 2004

The lipase and phospholipase activities of meals of resting seeds of C. roxburghianum were studied at different temperatures, solvents and pH. Both the enzymes showed the maximum activities at $40^{\circ}C$ and in n-heptane used as solvent. However, lipase showed maximum activities at two different pH, one at pH 5 (acidic) and other at pH 8 (alkaline) whereas phospholipase showed only one pH optimum at pH 8. During the course of germination, the lipase showed an increase whereas reverse was the case with phospholipase.

• Archives of Pharmacal Research
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• 제17권6호
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• pp.405-410
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• 1994

The present study was undetertaken to demonstrate whether or not angiotensin II activates a phopholipase D in rabbit kidney proximal tubule cells. By measuring the formation of [$^3H$] phosphatidic acid and [$^3H$]diacylglycerol. This result suggests that some phosphatidic acid seems to be formed directly from phosphatidylcholin by the action of phopholipase D, not from the action of diacylglycerol kinase on the diacylglycerol. In addition the other mechanisms by which phospholipase D is activated was examined. We have found that phospholipase D was activited by extracellular calium ion. It has also been shown that angiotensin II may activate phosphoilpase D through protein kinase C-independent pathway.

• Tuberculosis and Respiratory Diseases
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• 제69권4호
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• pp.256-264
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• 2010

Background: According to the notion of the immunoregulatory functions of moxifloxacin (MFX), the effect of MFX on the neutrophilic respiratory burst in conjunction with the expression of cytosolic phospholipase $A_2$ ($cPLA_2$) was investigated. Methods: The effects and possible mechanisms of MFX on neutrophilic respiratory burst in oleic acid (OA)-induced acutely injured rats lung and OA-stimulated, isolated murine neutrophils were probed, associated with the expression of cytosolic phospholipase $A_2$ in vivo and in vitro. Results: In the OA-induced acutely-injured lungs, neutrophils were accumulated, which was attenuated by MFX. The parameters denoting a neutrophilic respiratory burst, such as nitro blue tetrazolium reaction, cytochrome-c reduction, neutrophil aggregation, $H_2O_2$ production in neutrophils revealed increased neutrophilic respiratory burst by OA, and MFX decreased all of these parameters. In addition, the enhanced expression of $cPLA_2$ in the lung and isolated murine neutrophils by OA were decreased by MFX. Conclusion: MFX suppresses the OA-induced neutrophilic respiratory burst by the suppression of $cPLA_2$ in neutrophils.

• KSBB Journal
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• 제5권2호
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• pp.119-124
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• 1990

다중 교반형 생물반응기 내에서 배추 PLD에 의한 인 지방질의 염기 가수분해 반응 및 염기전이 반응에 대한 특성 실험에서 다음과 같은 결론을 얻었다. 반응 최적 조건으로서 pH 5.6, 온도 37$^{\circ}C$였고 반응 촉진제로서 $Ca^2^+$의 농도는 가수분해 반응시 20mM, 염기전이 반응에서는 40mM이었다. Diethylether와 butylacetate도 강력한 반응촉진제로서 반응성을 높였고 이들의 농도는 20%가 효과적이었으며, 반면에 EDTA 및 $Ba^2^+,Mn^2^+,Zn^2^+$등은 PLD의 활성을 강력하게 저해하였다, 염기 수용체로서 glycerol을 비롯한 알콜 화합물은 대부분이 반응성을 양성으로 나타내었으며 15종의 알콜 화합물 가운데 glycerol, ethyleneglycol, propyleneglycol등이 반응성이 높게 나타났으며 이들의 최적농도는 20%가 효과적이었다.