• Applied Biological Chemistry
• /
• 제40권3호
• /
• pp.202-208
• /
• 1997

콩 뿌리조직의 이온 흡수와 관련된 생리활성을 조사하기 위하여 뿌리조직으로부터 마이크로솜을 분리하였고, 마이크로솜 ATPase (이온점프) 활성을 분광학적 방법인 enzyme-coupled 분석방법에 따라 측정하였다. 마이크로솜 ATPase의 활성에 미치는 여러 가지 이온의 효과 또는 ATPase의 이온선택성을 조사하기 위하여 $10mM\;Na^+$과 $120mM\;K^+$을 포함하는 대조용액에서의 평균활성을 측정한 결과 190 nmol/min/mg protein으로 나타났다. 대조활성에 비하여 $Na^+$을 포함하지 않은 $130mM\;K^+$ 용액에서는 활성이 150%로 증가하였고, $K^+$을 포함하지 않은 $130mM\;Na^+$ 용액에서는 활성이 63%로 감소되었다. 반응용액의 $K^+$ 농도에 따른 활성변화를 측정한 결과, ATPase의 활성은 외부용액의 $K^+$ 농도 증가에 따라 활성이 증가됨을 알 수 있었다. 또한 마이크로솜 ATPase 활성은 반응용액의 pH 감소에 따라 증가되어 $pH\;6{\sim}7$에서는 비교적 높은 활성을 보였으나, pH 8 이상에서는 급격히 활성이 감소되었고, pH 9에서는 80%이상의 활성이 저해되었다. $Ca^{2+}$에 의한 이온펌프의 활성조절 여부를 평가하기 위해서 마이크로솜 내부 및 외부의 $Ca^{2+}$에 의한 ATPase 활성변화를 측정하였다. 마이크로솜 ATPase의 활성은 반응액의 $Ca^{2+}$ 농도가 낮아질수록 증가하여 $10^{-9}M$ 이하에서 최대활성이 관측되었고, $Ca^{2+}$ 농도가 증가할수록 활성은 감소하여 $500\;{\mu}M$ 전후에서 50%의 활성이 감소하였다. 또한 ATPase의 활성은 마이크로솜 내부의 $Ca^{2+}$ 농도증가에 의해서 저해되어, $Ca^{2+}\;ionophore\;A23187$처리에 의한 외부의 $Ca^{2+}$ 유입에 의해서 약30%의 활성감소를 보였으며, EGTA 처리에 의한 $Ca^{2+}\;chelation$에 의해서 마이크로솜 내부의 $Ca^{2+}$ 농도가 감소되었을 때, ATPase 활성은 증가하였다. 위의 조건에서 실제 마이크로솜 내부로의 $Ca^{2+}$ 유입 여부는 $‘Ca^{2+}’$를 이용하여 확인하였다. 이상의 결과는 마이크로솜 막에 위치한 ATPase의 내부 및 외부에 $Ca^{2+}$에 의한 효소활성 조절부위가 각각존재함을 시사한다.

• The Korean Journal of Physiology
• /
• 제20권2호
• /
• pp.157-164
• /
• 1986

Since it has been reported that vanadate inhibits $Ca^{++}-ATPase$ activity without affecting $Ca^{++}$ uptake, this study was undertaken to investigate the effects of vanadate on $Ca^{++}-ATPase$ activity and $Ca^{++}$ uptake in the sarcoplasmic reticulum of rat skeletal muscle. The following results were obtained. 1) $Ca^{++}$ activated ATPase activity of the intact sarcoplasmic reticulum was significantly inhibited when vanadate was added to the incubation medium at concentration greater than $10^{-6}\;M$. However $Mg^{++}$-ATPase activity of the intact SR was not affected by vanadate at concentrations ranging from $10^{-7}\;to\;10^{-4}\;M.$ Similarly, $Ca^{++}-ATPase$ activity in sonicated sarcoplasmic reticulum was significantly reduced by vanadate at a concentration $10^{-7}$ M or higher. 2) The uptake of $Ca^{++}$ by isolated sarcoplasmic reticulum was also inhibited by vanadate under the conditions where the turnover rate of $Ca^{++}-ATPase$ was made to increase. These results suggest that the inhibition of $Ca^{++}$ uptake by vanadate may be correlated with that of $Ca^{++}-ATPase$ if experimental conditions are properly set.

• Molecules and Cells
• /
• 제20권2호
• /
• pp.247-255
• /
• 2005

Three different catalase cDNA clones (CaCat1, CaCat2, and CaCat3) were isolated from hot pepper (Capsicum annuum L.), and their expression patterns were analyzed at the levels of mRNA and enzyme activity. Northern hybridization showed that the three catalase genes were differentially expressed in various organs, and that expression of CaCat1 and CaCat2 was regulated differently by the circadian rhythm. In situ hybridization revealed different spatial distributions of CaCat1 and CaCat2 transcripts in leaf and stem. In response to wounding and paraquat treatment, CaCat1 mRNA increased at 4-12 h in both paraquat-treated and systemic leaves. In contrast, wounding had no significant effect on expression of the catalase genes. The increase of catalase activity in the paraquat-treated and systemic leaves paralleled that of CaCat1 mRNA, but did not match that of CaCat1 mRNA in paraquat-treated stems. Our results suggest that CaCat1 may play a role in responses to environmental stresses.

• 자연과학논문집
• /
• 제9권1호
• /
• pp.1-7
• /
• 1997

칼슘/calmodulin-의존적 단백질 인산화 효소 II (CaMK-II)는 세포의 여러 기능을 조절하는 다양한 단백질들을 인산화시키는 효소이다. 세포 내부의 칼슘의 농도는 세포의 주기에 따라 변하므로 CaMK-II의 활성도 역시 세포주기에 따라 변하는 지를 조사함으로 세포주기에서의 CaMK-II의 역할을 알아보려 하였다. NIH3T3 세포를 CaMK-II의 활성도에는 전혀 영향을 주지 않는 여러 가지 약제로 처리하여 세포주기상의 특정한 시점에 동일하게 정지시킨 후, 세포내의 CaMK-II 활성도를 합성 펩타이드기질을 이용하여 측정하였다. 또한 일정 시점으로부터 동조화된 세포내의 CaMK-II의 활성도의 변화를 측정하여 한 세포주기 동안 효소의 활성도 변화의 양상을 조사하였다. 세포주기상 각각 G0, G1, G1/S, G2/M기에 정지된 세포내의 CaMK-II 총활성도는 대조군과 차이가 없었으나 M기에서는 낮았다. 그러나 자가인산화에 의한 CaMK-II의 칼슘-비의존성 활성도는 M기에서 가장 높았다. 이러한 양상은 G1기에서부터 동조화된 세포내 CaMK-II의 칼슘-비의존성 활성도 변화 양상과도 일치하였다. CaMK-II의 생리학적 의미를 지닌 활성도는 인산화에 의한 calcium-비의존성 활성도임을 비추어 볼 때 M기에서 CaMK-II가 세포분열의 과정에서 중요한 기능을 하고 있음을 보여주고 있다.

• 한국발생생물학회지:발생과생식
• /
• 제15권1호
• /
• pp.31-39
• /
• 2011

Change in intracellular $Ca^{2+}$-concentration ($[Ca^{2+}]_i$) is an essential event for egg activation and further development. $Ca^{2+}$ ion is originated from intracellular $Ca^{2+}$-store via inositol 1,4,5-triphosphate receptor and/or $Ca^{2+}$ influx via $Ca^{2+}$ channel. This study was performed to investigate whether changes in $Ca^{2+}$/calmodulin dependent protein kinase II (CaM KII) activity affect $Ca^{2+}$ influx during artificial egg activation with ethanol using $Ca^{2+}$ monitoring system and whole-cell patch clamp technique. Under $Ca^{2+}$ ion-omitted condition, $Ca^{2+}$-oscillation was stopped within 30 min post microinjection of porcine sperm factor, and ethanol-induced $Ca^{2+}$ increase was reduced. To investigate the role of CaM KII known as an integrator of $Ca^{2+}$- oscillation during mammalian egg fertilization, CaM KII activity was tested with a specific inhibitor KN-93. In the eggs treated with KN-93, ethanol failed to induce egg activation. In addition, KN-93 inhibited inward $Ca^{2+}$ current ($I_{Ca}$) in a time-dependent manner in whole-cell configuration. Immunostaining data showed that the voltage-dependent $Ca^{2+}$ channels were distributed along the plasma membrane of mouse egg and 2-cell embryo. From these results, we suggest that $Ca^{2+}$ influx during fertilization might be controlled by CaM KII activity.

• Journal of Photoscience
• /
• 제2권1호
• /
• pp.1-5
• /
• 1995

The activity of phospholipase A$_2$ (PLA$_2$) was identified and characterized from cytosolic and membrane fractions of oat cells, respectively. PLA$_2$ activity was determined fluorometrically in the presence of serum albumin using phospholipids labeled at sn-2-acyl position with 10-pyrenyldecanoic acid. When the cell-free extracts of oat tissues were fractionated by ultracentrifugation at 100,000 x g and the PLA$_2$ activity was assayed, we found that most of the PLA$_2$ activity was revealed from the cytoplasmic fraction rather than from the membrane fraction. The activity of cytosolic PLA$_2$ was dependent on Ca$^{2+}$ concentration and the optimum concentration of Ca$^{2+}$ was found to be 100 $\mu$M. It was also found that PLA$_2$ could be translocated toward the membrane site from the cytosol upon increasing Ca$^{2+}$ concentration. These results might suggest that an increased [Ca$^{2+}$]$_i$ by phytochrome action could promote the translocation of the cytosolic PLA$_2$ toward the membrane site.

• Journal of Plant Biology
• /
• 제32권4호
• /
• pp.265-274
• /
• 1989

The effect of Ca2+ on auxin-induced ehtylene production in etiolated mungbean (Vigna radiata W.) hypocotyls was studied. Auxin-induced ethylene production by mungbean seedlings which had been germinated in the presence of 5-10mM Ca2+ (High Ca2+ ; HC) is greater than that by seedlings which had been germinated in distilled water (Low Ca2+ ; LC). The effect of Ca2+ on auxin-induced ethylene production was greatly increased after 12hr of incubation period. The stimulation of auxin-induced ethylene production by Ca2+ was specific, since divalent cations, such as Mg2+ and Mn2+ did not enhance auxin-induced ethylene production. Calcium also promoted ethylene evoluation induced by methionine and 1-Aminocyclopropane-1-carboxylic acid(ACC). The effect of Ca2+ on auxin-induced ethylene production was not caused by increase in free IAA or ACC contents of hypocotyl tissue. Dimethyl sulfoxide and Triton X-100, that disrupts the emembranes, inhibited ethylene production to a greater extent in LC segments than in HC segments. Addition of Ca2+ to the incubation medium for LC segments resulted in enchancement of ethylene production probalby because the membrane integrity is supported under these conditions. Comparison of activity of Ethylene Forming Enzyme(EFE) in LC and HC hypocotyl segments indicated that the enzyme activity of HC was about 2 times higher than that of L.C. It is suggested that Ca2+ increases the activity of plasma membrane-bound EFE through its stabilizing effect onn the membrane, which in turn brings about promotion of ethylene production.

• Journal of Microbiology and Biotechnology
• /
• 제18권2호
• /
• pp.365-368
• /
• 2008

Calcium entry through $Ca_v3.2Ca^{2+}$ channels plays essential roles for various physiological events including thalamic oscillation, muscle contraction, hormone secretion, and sperm acrosomal reaction. In this study, we examined how protein tyrosine phosphatases or protein tyrosine kinases affect $Ca_v3.2Ca^{2+}$ channels reconstituted in Xenopus oocytes. We found that $Ca_v3.2$ channel activity was reduced by 25% in response to phenylarsine oxide (tyrosine phosphatase inhibitor), whereas it was augmented by 19% in response to Tyr A47 or herbimycin A (tyrosine kinase inhibitors). However, other biophysical properties of $Ca_v3.2$ currents were not significantly changed by the drugs. These results imply that $Ca_v3.2$ channel activity is capable of being increased by activation of tyrosine phosphatases, but is decreased by activation of tyrosine kinases.

• 대한한의학회지
• /
• 제18권1호
• /
• pp.198-207
• /
• 1997

To explore the action mechanism of Ijintang in the brain, the authors investigated the effects of Ijintang fractions on MgNaK ATPase and MgCa ATPase in rat brain synaptosomes prepared from cerebral cortex. The activities of MgNaK ATPase and MgCa ATPase were assayed by the level of inorganic phosphate liberated from the hydrolysis of ATP. Fraction WH-95-7 at the concentration of $10^{-2}%$ decreased the activity of MgNaK ATPase about 34.1% and also reduced the activity of MgCa ATPase about 49.3% But, other fractions (WB-95-7, WC-95-7, MB-95-7, MC-95-7, MH-95-7) did not significantly changed the activities of the MgNaK ATPase and MgCa ATPase The decreased activity of MgNaK ATPase by WH-95-7 will decrease the rate of $Ca^{2+}$ efflux, probably via an Na-Ca exchange mechanism and will increase the rate of $Ca^{2+}$ entry by the depolarization of nerve terminals. The reduced activity of MgCa ATPase by WH-95-7 will result in the decreased efflux of $Ca^{2+}$. As a conclusion, it can be speculated that lithium elevates the intrasynaptosomal $Ca^{2+}$ concentration via inhibition of the activities of MgNaK ATPase and MgCa ATPase. and this increased $[Ca^{2+}]i$ will cause the release of neurotransmitters.

• Journal of Plant Biology
• /
• 제34권4호
• /
• pp.261-266
• /
• 1991

The hairy root was induced form potato tuber disc by infection of a. rhizogenes. The detection of the agropine and mannopine by paper electrophoresis confirmed that induced hairy root was transformed by A. rhizogenes. The activity of peroxidase was the highest at 5 weeks and isozyme pattern of peroxidase revealed 3 cathodic bands and 2 anodic bands and new C4 band(pI 4.6) was observed at 7 weeks after cultivation in hairy root was isoelectric focusing. To study the effect of Ca2+ on cell wall formation in hairy root, channel blocker of Ca2+ was treated. The activity of $\beta$-glucan synthetase II(GS II) related to cell wall synthesis was inhibited by about 50% in diltiazem and flunarizine treatment than that of control, but stimulated in CaCl2 treatment. Therefore these results showed that Ca2+ might be an effective factor in the cell wall formation. The activity of GS II by NaF treatment was increased by about 30%. This result suggested that the activity GS II is changed through phosphorylation process.