• Applied Biological Chemistry
• /
• v.40 no.3
• /
• pp.202-208
• /
• 1997

In order to investigate the mechanisms of epithelial ion transports, microsomes of soybean roots were prepared and the activity of microsomal ATPases was measured by an enzyme-coupled assay. The effects of various ions were evaluated on the total activity of microsomal ATPases and the average activity was 190 nmol/min/mg protein in the control solution containing $10\;mM\;Na^+\;and\;120\;mM\;K^+$. The activities were increased to 150% and decreased to 63% of the control activity in the solution containing $130\;mM\;K^+$ without $Na^+$ and in the solution containing $130\;mM{\;}Na^+$ without $K^+$, respectively. In general, the activity of microsomal ATPase was increased by$K^+$ in a concentration-dependent manner The activity was also increased at lower pH and relatively higher activities were observed in the pH range of $6{\sim}7$. However, the activity was decreased at weak alkaline $pH\;and{\sim}80%$ of the activity was inhibited at pH 9. Since intracellular $Ca^{2+}$ has been known to control the activity of various enzymes, we have investigated the effects of intra-and extrarnicrosomal $Ca^{2+}$ on the activity of microsomal ATPases. The maximal activity was obtained at the extrarnicrosomal $Ca^{2+}$ concentrations below 1 nM. The activity was gradually decreased by increasing $‘Ca^{2+}’$ concentration and 50% inhibition was observed at ${\sim}500{\;}{\mu}M{\;}Ca^{2+}$. The increase in luminal $Ca^{2+}$ concentration also inhibited the activity of microsomal ATPase. When the influx of external $Ca^{2+}$ was induced by $Ca^{2+}$ ionophore A23187 treatment, the activity was decreased by 30%; however, it was recovered by EGTA-induced chelation of $Ca^{2+}$. These results suggest that the presence of $Ca^{2+}$ regulation sites on both cytoplasmi and luminal sides of microsomal ATPases.

• The Journal of Natural Sciences
• /
• v.9 no.1
• /
• pp.1-7
• /
• 1997

Calcium/calmodulin-dependent protein kinase II (CaMK-II) is responsible for the phosphorylation of proteins involved in various cellular functions. Since the level of intracellular calcium ($Ca_2+$) oscillate during the cell cycle, it is expected that the activity of CaMK-II is also dependent on the cell cycle. The kinase activity in NIH3T3 cells which were arrested at or released from certain phase of the cell cycle was measured and compared to that in the normally growing asynchronous control cells to investigate whether the activity of this kinase is cell cycle-dependent. Cells were arrested at G0, G1, G1/S, G2/M and M phase, respectively by use of various drugs which do not have any effect on the kinase activity of CaMK-II at G0, G1, G1/s and G2/M phase was similar to that of the control cells, whereas lower at M. Calcium-independent activity of CaMK_II by autophosphorylation was higher at M and, thus, higher autonomy at M, which represented the physiologically relevant activity of CaMK-II. A similar pattern of activity change of the kinase was demonstrated during the cell cycle of synchronized cells which were released from G1 arrest. These results indicate that the activity of CaMK-11 is cell cycle-dependent and is activity during the mitosis.

• The Korean Journal of Zoology
• /
• v.38 no.1
• /
• pp.125-135
• /
• 1995

붉은지렁이 (Lumbricus rubellus)의 체내에 존재하는 prophenoloxidase-phenoloxidase(prPO$\longrightarrow$PO)의 활성계는 몇 종류의 다른 경로에 의해 활성화 됨을 발견하였다 Propo는 exogenous trypsin $\beta$ 1.3-glucan, Ca2' 이온. lipopolysaccharide (LPS) 및 열처리 등에 의하여 활성도가 증가 되었고 Ca2' 이온이 나머지 4가지 종류의 처리와 함께 병행되었을 때 그 효과가 더욱 증가하였다 Propo의 활성도는 LPS나 Ca2' 이온의 농도가 각각 1 5H 10-s g Lps/r리, 15 mM(Ca2')의 농도에서 propo의 최대활성치를 나타냈으나 그 이상의 농도에서는 propo의 활성이 오히려 감소하였다. LPS. $\beta$ 1,3-glucan 및 Ca2' 이온 등은 trypsin 억제인자인 soybean trypsin inhibitor(571)가 함께 존재할 경우 전혀 propo를 활성화 시킨지 못하는 것으로 미루어 $\beta$ 1,3-glucan 및 Ca2' 이온 등은 체내의 trypsin 유사 효소의 활성을 증가시켜 궁극적으로는 proPO$\longrightarrow$PO의 활성화 반응에 간접적으로 작용한다고 생각되었다. 한편. 571의 존재하에서도 50"C의 열처리는 propo의 활성화에 아주 효과적인 물리적 요인으로 작용하였다. 따라서 열처리는 Ca2'이나 LPS. f 1,3-glucan파는 달리 직접적으로 proPO$\longrightarrow$PO의 활성화 반응에 작용하는 것으로 생각되어 붉은 지렁이의 체내에서 proPO가 활성화되는 괴정(propo-activating system)에는 최소한 2가지 이상의 경로가 있다고 생각된다.생각된다.

• Applied Biological Chemistry
• /
• v.39 no.3
• /
• pp.189-194
• /
• 1996

The effects of scorpion (Leiurus quinquestriatus hebraeus, Lqh) venom were evaluated on the activities of microsomal $Ca^{2+}-ATPase$ and $Ca^{2+}$ release channel prepared from the epithelial cells of pig airway. Whole venom of Lqh $(120\;{\mu}g/ml)$ increased the activity of microsomal $Ca^{2+}-ATPase$ about 32% in the tight-sealed microsomes and about 28% in the Triton X-100-treated or $Ca^{2+}$ ionophore A23187-treated leaky microsomes. Thapsigargin, a specific antagonist of $Ca^{2+}-ATPase$, inhibited 42% of total ATPase activity and also completely blocked the effects of Lqh venom, suggesting that Lqh venom directly activiates the microsomal $Ca^{2+}-ATPase$. In order to determine if Lqh venom increases the microsomal uptake of $^{45}Ca^{2+}$, Lqh venom was added in the uptake medium. The Lqh venom increased microsomal $^{45}Ca^{2+}$ uptake up to ${\sim}20%$ and the increase was only observed when heparin, an antagonist of $InsP_3$ receptor channel, was added in the uptake medium. Lqh venom in the absence of heparin unexpectedly decreased the rate and the amount of $^{45}Ca^{2+}$ uptake. These results were explained by simultaneous increases in $^{45}Ca^{2+}$ release as well as $^{45}Ca^{2+}$ uptake by Lqh venom. Lqh venom itself increased the release of $^{45}Ca^{2+}$ as much as $^{45}Ca^{2+}$ release by $4\;{\mu}m\;InsP_3$, implying that Lqh venom also activates $InsP_3$ receptor, microsomal $Ca^{2+}$ release channel. Based on these results, we suggest that the Lqh venom consists of at least two components; one activates the $InsP_3$ receptor and the other avates the $Ca^{2+}-ATPase$. Currently we a investigating the chemical and electrophysiological properties of the active components of Lqh venom.

• Korean Journal of Weed Science
• /
• v.17 no.1
• /
• pp.59-65
• /
• 1997

Bentazon 6-hydroxylase (B6H) and cinnamic acid 4-hydroxylase (CA4H) activities were determined in rice (Oryza sativa L.) microsomes to study methods of enhancing cytochrome P-450 mediated aryl hydroxylation of bentazon by hydoxylase inducing compounds. Pretreating rice seeds with 1,8-naphthalic anhydride at 0.5-2% and fenclorim at 5 and 10 ${\mu}M$ increased B6H and CA4H activities. Treatments of rice seedling with ethanol 2.5% enhanced B6H and CA4H activities, and with phenobarbital at 12 mM enhanced B6H activity, and CA4H activity was enhanced at 2 mM. B6H activity was synergistically enhanced by combined treatments of ethanol 2.5 or 5% and phenobarbital 8 or 12mM and also that of 1,8-naphthalic anhydride 0.5 or 1% and phenobarbital 8 or 12 mM, but CA4H activity was decreased by combined treatment. Five-day-old rice seedlings showed higher B6H and CA4H activities which decreased with seedling age.

• Progress in Medical Physics
• /
• v.14 no.1
• /
• pp.54-67
• /
• 2003

The voltage-dependence of N-type calcium current inactivation is U-shaped with the degree of inactivation roughly mirroring inward current. This voltage-dependence has been reported to result from a purely voltage-dependent mechanism. However, $Ca^{2＋}$-dependent inactivation of N-channels has also been reported. We have investigated the role of $Ca^{2＋}$ in N-channel inactivation by comparing the effects of $Ba^{2＋}$and $Ca^{2＋}$ on whole-cell N-current in rat superior cervical ganglion neurons. For individual cells in-activation was always larger in $Ca^{2＋}$ than in $Ba^{2＋}$ even when internal EGTA (11 mM) was replaced with BAPTA (20 mM). The inactivation vs. voltage relationship was U-shaped in both divalent cations. The enhancement of inactivation by $Ca^{2＋}$ was inversely related with the magnitude of inactivation in $Ba^{2＋}$ as if the mechanisms of inactivation were the same in both $Ba^{2＋}$ and $Ca^{2＋}$. In support of this idea we could separate fast ( ${\gamma}$ ～150 ms) and slow ( ${\gamma}$ ～ 2500 ms) components of inactivation in both $Ba^{2＋}$and $Ca^{2＋}$ using 5 sec voltage steps. Differential effects were observed on each component with $Ca^{2＋}$ enhancing the magnitude of the fast component and the speed of the slow component. The larger amplitude of fast component indicates that the more channels inactivate via this pathway with $Ca^{2＋}$ than with $Ba^{2＋}$, but the stable time constants support the idea the fast inactivation mechanism is identical in $Ba^{2＋}$and $Ca^{2＋}$. The results do not support a $Ca^{2＋}$-dependent mechanism for fast inactivation. However, the $Ca^{2＋}$-induced acceleration of the slowly inactivating component could result from a $Ca^{2＋}$-dependent process.

• Journal of Korean Biological Nursing Science
• /
• v.1 no.1
• /
• pp.25-41
• /
• 1999

Physiological activity of osteoblast including bone formation is known to be closely related to the increase of intracellular $Ca^{2+}$ activity($[Ca^{2+}]_i$) in osteoblast. $Ca^{2+}$ is an important intracellular messenger in diverse cellular functions, and regulation of its level is mediated by the transmembrane $Ca^{2+}$ movement via $Ca^{2+}$ channels, $Na^+-Ca^{2+}$ exchange, and by intracellular $Ca^{2+}$ movement through the intracellular stores. The purpose of this study is to investigate how the intracellular $Ca^{2+}$ is regulated in osteoblast-like cells(OLCs) by measuring $Ca^{2+}$ activity with cell imaging technique. OLCs were isolated from femur and tibia of neonatal rats, and cultured for 7 days. Cultured OLCs were loaded with a $Ca^{2+}$-sensitive fluorescent dye, Fura-2, and fluorescence images were monitored with a cooled CCD camera. The images were processed and analyzed with an image analyzing software. The results were as follows. (1) $[Ca^{2+}]_i$ of OLC decreased as the $Ca^{2+}$ concentration in the superfusing Tyrode solution was lowered. When $Na^+$ concentration in the superfusing solution was decreased, $[Ca^{2+}]_i$ increased.. These suggest that $Ca^{2+}$ flux occurs via the $Na^+-Ca^{2+}$ exchange mechanism. (2) When $Na^+$ in the superfusing solution was removed. a transient $Ca^{2+}$, increase($Ca^{2+}$ spike) was occasionally observed. However, $Ca^{2+}$ spike was not observed after adding 1 ${\mu}M$ thapsigargin. This implies that the generation of $Ca^{2+}$ spike is mediated by the release of $Ca^{2+}$ from endoplasmic reticulum(ER). (3) As the $Ca^{2+}$ concentration in the superfusing solution was raised, the frequency of 0mM $Na^+$-induced $Ca^{2+}$ spike increased, suggesting that $Ca^{2+}$-induced $Ca^{2+}$ release(CICR) mechanism exists. (4) After $[Ca^{2+}]_i$ was decreased with the superfusion of $Ca^{2+}$-free solution containing thapsigargin, the recovery of $[Ca^{2+}]_i$ with reperfusion of 2.5mM $Ca^{2+}$ solution transiently exceeded the control level, suggesting that the depletion of $Ca^{2+}$ in ER induces $Ca^{2+}$ influx from extracellular medium via store-operated $Ca^{2+}$ influx(SOCI) mechanism. (5) $[Ca^{2+}]_i$ was not affected by the superfusion of 25mM $K^+$ Tyrode solution. These results suggest that intracellular $Ca^{2+}$ activity in osteoblast is regulated by transmembrane $Ca^{2+}$ flux via $Na^+-Ca^{2+}$ exchange, $Ca^{2+}$ release from the internal store (ER) via $Ca^{2+}$-induced $Ca^{2+}$ release, and store-operated $Ca^{2+}$ influx across the cell membrane.

• The Korean Journal of Zoology
• /
• v.10 no.2
• /
• pp.1-8
• /
• 1967

토끼의 골격근 homogenate에서 23,000$\times$G, 60 분간의 원심분리와 얻은 근 microsome의 ATPase 활성, 근수축에 대한 이완작용, 및 Ca 의 흡수작용을 여러 가지 조건에서 측정하였다. ATPase 활성은 Ca++ Mg++ 양 이온의 존재에 의하여 활성화되며 , 5 mM Mg++ 의 존재하에서는 Ca++ 의 최적농도는 0.1mM이다. Oxalate의 존재하에서는 1 mM 의 Ca++ 이 최적농도이므로 oxalate의 작용은 불용성 Ca-oxalate의 작용은 불용성 Ca-oxalate를 microsome vesicle so 및 medium 내에 침전시켜 유리 Ca++ 농도를 저하시키는 것이라고 생각된다. Microsome의 이완작용은 조제후 120 시간까지 시간에 따라 감소되어 가나, 그이 ATPase 활성은 거의 변화가 없는 것으로 보아 Ca++ + Mg++ -의존성 ATPase 는 이완작용에는 직접 관련이 없는 것으로 해석된다. Oxalatedmlwhswo는 microsome의 Ca++ 흡수량을 현저히 증대시키며 동시에 흡수포화에 도달하는 시간을 지연시킨다. Oxalate의 이러한 효과도 Ca-oxalate의 형성에 기인하는 것으로 해석된다. Microsome 내에 축적되는 Ca 의 량은 ATP 농도가 커질수록 많아진다. 그러나 축적된 Ca 의 량과 ATP 농도사이에 화학정량론적 관계는 없는 것같다.

• Bulletin of Food Technology
• /
• v.18 no.2
• /
• pp.52-58
• /
• 2005

최근 20여년 동안 Panax ginseng의 다양한 효과가 연구 되어져 왔다. Panax ginseng의 주요 활성 성분인 ginsenosides는 오직 인삼에서만 발견되어지는 saponin이다. 최근 들어 신경, 非신경 또는 복합적으로 분포된 세포에서 ginsenoside가 $Ca^2+$, $K^+$,$Na^+$,$Cl^-$ channel이나 ligand gated ionchannel (5-HT3, nicotinic acetylcholine, NMDA receptor)과 같은 다양한 ion channel을 조절하는증거들이 발표되고 있다. Ginsenoside는 voltage-dependent $Ca^2+$, $K^+$,$Na^+$ channel의 활성을 억제하는 반면 $Ca^2+$-activated $Cl^-$ channel이나 $Ca^2+$-activated $K^+$ channel의 활성은 증가 시키는 것으로 나타났다. 또한 흥분성 ligand-gated ion channel인 $5-HT_3$, nicotinic acetylcholine, NMDA receptor의 활성은 억제한다. 본 총설에서는 현재까지 알려진 ion channel 활성에 대한 ginsenoside의 조절작용과 이것으로 인해 어떻게 생물학적 효능과 연결이 되어있는지에 대하여 이야기하고자 한다.

• KSBB Journal
• /
• v.11 no.5
• /
• pp.518-523
• /
• 1996

The sensor to determine ATPase activities was consisted of an immobilized enzyme membrane(purine nucloside phosphoryrase and xanthine oxidase) and an oxygen electrode. The proposed sensor was used for the determination of $K^+-, Ca^{2}+- and Mg^{2+}-$ATPase activities in several fish muscle proteins such as Thunnus albacares(Yellowfin tuna), Tetrapturus audax(Striped marlin), Prognichthys agoo(Japanese flyingfish), and Cypvinus carpio(Carp). $K^+-, Ca^{2}-$ATPase activities measured by the proposed sensor system were in good agreement with the results obtained by a conventional colorimetric assay. One cycle of assay could be completed within 3mlnutes.