• Archives of Pharmacal Research
• /
• v.24 no.3
• /
• pp.202-206
• /
• 2001

The effects of various sedative cyclopeptides and peptide alkaloids from the Zizyphus species on calmodulin-dependent $Ca^{2+}$ -ATPase and phosphodiesterase were Investigated. Calmodulin-induced activation of $Ca^{2+}$-ATPase was strongly inhibited by sanjoinine-A dialdehyde (IC_{50}$, 2.3$\mu\textrm{m}$), -Ah1 (IC_{50}$, 4.0$\mu\textrm{m}$), -A (IC, 4.6$\mu\textrm{m}$), and -G2 (IC_{50}$, 7.2$\mu\textrm{m}$), while calmodulin-induced activation of phosphodiesterase was strongly inhibited by both deachuine- S10 (IC_{50}$, 4.9$\mu\textrm{m}$) and sanjoinine-D (IC_{50}$, 9.0$\mu\textrm{m}$). The inhibitory activity of the various cyclopeptides and peptide alkaloids on $Ca^{2+}$-ATPase was found to correlate well with their Sedative activity.

• Fisheries and Aquatic Sciences
• /
• v.8 no.1
• /
• pp.10-16
• /
• 2005

Conditions for sufficient and rapid distribution of a cryoprotectant (sorbitol solution) into intact fish muscle (Oncorhynchus mykiss) were studied as changing in the residual Ca2+ ATPase activity during freeze/thaw cycling. Chunks of the fish muscle were immersed in 4 concentrations of sorbitol solutions ($20\%$, $30\%$, $45\%$, and $60\%$) by a shaker mechanism at 5$^${circ}C. Whole immersion samples (W) showed a higher value of the residual Ca2+ ATPase activity than those in the untreated controls (C), except in the treated controls (TC), while less effect of immersion concentration could be found. Comparing the extent of penetration of sorbitol into the surface layer to inner layer of immersed fish chunks, outer portion samples achieved excellent cryoprotection with $100\%$ of the residual ATPase activity values or more. For the inner portion samples, $30\%$ and $45\%$ sorbitol solution treatments indicated a higher ATPase activity than $60\%$ treatment. At high concentrations, mass transfer rates during osmotic dehydration might berapid and it causes faster surface drying by dewatering at surface solute layer. Periodically immersed and relaxed samples, W (5-3-1), led to good cryoprotection effect: W (5-3-1) indicated high residual Ca2+ ATPase activity values and the residual ATPase activity values excess $100\%$ in immersion of $30\%$ and $45\%$ sorbitol solutions.

• Applied Biological Chemistry
• /
• v.42 no.2
• /
• pp.116-122
• /
• 1999

In order to characterize the property of $Ca^{2+}$ transport in plant cell, microsomes were prepared from the roots of tomato and microsomal $^{45}Ca^{2+}$ uptake was measured. When 1 mM vanadate, a selective inhibitor of P-type ATPases, 50 mM $NO_3^-$, a specific inhibitor of vacuolar $H^{+}-ATPase$, and both of these inhibitors were treated, the microsomal $^{45}Ca^{2+}$ uptakes were inhibited by 20, 33 and 47%, respectively. The inhibitory effects of these two inhibitors were investigated by using a protonophore, gramicidin. When the chemical gradient of $H^{+}$ was relieved by gramicidin, the uptake was decreased by 30%, implying the presence of $Ca^{2+}/H^+$ antiporter in the microsomal membrane. In the $^{45}Ca^{2+}$ uptake experiment, the effect of gramicidin was independent of vanadate-induced inhibition. However, when the activity of vacuolar $H^{+}-ATPase$ was inhibited by $NO_3^-$, the effect of gramicidin was severely decreased. Meanwhile, thapsigargin, a specific antagonist of ER/SR-type $Ca^{2+}-ATPase$, inhibited the microsomal $^{45}Ca^{2+}$ uptake and the maximum inhibitory effect was obtained at $10\;{\mu}M$. The effect of thapsigargin was blocked by $NO_3^-$ and gramicidin, but not by vanadate. These results imply that vanadate directly inhibits the activity of $Ca^{2+}-ATPase$; however, $NO_3^-$ and thapsigargin block the activity of $Ca^{2+}/H^+$ antiporter by inhibiting the vacuolar $H^{+}-ATPase$. In conclusion, the microsomal $^{45}Ca^{2+}$ uptakes are mediated by two major enzymes, $Ca^{2+}-ATPase$ and $Ca^{2+}/H^+$ antiporter in tomato root tissue.

• Microbiology and Biotechnology Letters
• /
• v.8 no.2
• /
• pp.113-117
• /
• 1980

The effects of divalant metal ions on the ATPase activity were studied by using my of ibrillar protein of rabbit (Chin-Chilla species) fed with vegetable oils. The results obtained were as follows : 1. The ATPase activity in myofibrillar protein of the is not significant to Rabbit exhibited a common biohapsic respnse, such as the ATPase activity is high at a lower ionic strength and low at a higher ionic strength. 2. The effect of EDTA on the ATPase activity of Myofibrillar protein extracted from Rabbit fed vegetable oils was tested by using various concentrations. The ATPase activity was inhibited from 0.2mM and over concentration of EDTA. 3. The ATPase activity in Myofibrillar protein was decreased remarkably in 0.2mM and over concentration for $Mg^{2+}$, and in 1.0mM and over concentration for $Ca^{2+}$. 4. in vitro, the digestibilities in A, B, C and D groups of Rabbit muscle treated with Papsin and Trypsin for 30 minutes at 36$^{\circ}C$ water bath were 71.66％, 73.87％ ； 70.62％, 77.93％ ； 67.93％, 76.52％ ； and 86.79％, 90.22%, respectively.y.

• The Korean Journal of Physiology
• /
• v.21 no.2
• /
• pp.157-167
• /
• 1987

Benzyl alcohol is known to have dual effect on the red blood cell shape change. At low concentration up to 50 mM benzyl alcohol transformed the shape from discocyte to stomatocyte by preferent binding to the inner hemileaflet, however, at higher concentratransformed the shape from discocyte to stomatocyte by preferential binding to the inner monolayer, however, at higher concentration above 50 mM benzyl alcohol transformed to echinocyte by affecting both monolayers. These results suggest that the effect of benzyl alcohol on the red blood cell shape and $Ca^{++}$ transport across cardiac cell membranes to assess the effects of the drug on the structures and functions of the biological cell membranes. The results are as follows: 1) Benzyl alcohol up to 40 mM caused progressive stomatocytic shap change of the red blood cell but above 50 mM benzyl alcohol caused echinocytic shape change. 2) Benzyl alcohol up to 40 mM inhibited both osmotic hemolysis and osmotic volume change of the red blood cell in hypotonic and hypertonic NaCl solutions, respectively. 3) Benzyl alcohol inhibited both Bowditch Staircase and Wood-worth Staircase phenomena at rat left auricle. 4) Benzyl alcohol at concentration of 5 mM increased $Ca^{++}-ATPase$ activity of red blood cell ghosts slightly but above S mM benzyl alcohol inhibited the $Ca^{++}-ATPase$ activity. 5) Benzyl alcohol at concentrations of 5 mM and 10 mM increased $Ca^{++}-ATPase$ activity slightly at rat gastrocnemius muscle S.R. but above 10 mM benzyl alcohol inhibited the $Ca^{++}-ATPase$ activity. Above results indicate that benzyl alcohol inhibit water permeability and $Ca^{++}$ transport across cell membranes in part via effects on the fluidity and transition temperatures of the bulk lipid by preferential intercalation into cytoplasmic monolayer and in part via other effect on the conformational change of active sites of the $Ca^{++}-ATPase$ molecule extended in cytoplasmic face.

• 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.

• The Korean Journal of Physiology and Pharmacology
• /
• v.3 no.2
• /
• pp.223-230
• /
• 1999

Alterations of cardiovascular function associated with various thyroid states have been studied. In hyperthyroidism left ventricular contractility and relaxation velocity were increased, whereas these parameters were decreased in hypothyroidism. The mechanisms for these changes have been suggested to include alterations in the expression and/or activity levels of various proteins; ${\alpha}-myosin$ heavy chain, ${\beta}-myosin$ heavy chain, ${\beta}-receptors,$ the guanine nucleotide-binding regulatory protein, and the sarcolemmal $Ca^{2+}-ATPase.$ All these cellular alterations may be associated with changes in the intracellular $Ca^{2+}$ concentration. The most important regulator of intracellular $Ca^{2+}$ concentration is the sarcoplasmic reticulum (SR), which serves as a $Ca^{2+}$ sink during relaxation and as a $Ca^{2+}$ source during contraction. The $Ca^{2+}-ATPase$ and phospholamban are the most important proteins in the SR membrane for muscle relaxation. The dephosphorylated phospholamban inhibits the SR $Ca^{2+}-ATPase$ through a direct interaction, and phosphorylation of phospholamban relieves the inhibition. In the present study, quantitative changes of $Ca^{2+}-ATPase$ and phospholamban expression and the functional consequences of these changes in various thyroid states were investigated. The effects of thyroid hormones on (1) SR $Ca^{2+}$ uptake, (2) phosphorylation levels of phospholamban, (3) SR $Ca^{2+}-ATPase$ and phospholamban protein levels, (4) phospholamban mRNA levels were examined. Our findings indicate that hyperthyroidism is associated with increases in $Ca^{2+}-ATPase$ and decreases in phospholamban levels whereas opposite changes in these proteins occur in hypothyroidism.

• The Korean Journal of Pharmacology
• /
• v.30 no.1
• /
• pp.117-124
• /
• 1994

Phospholamban is the regulator of $Ca^{2+}-ATPase$ in cardiac sarcoplasmic reticulum(SR). The mechanism of regulation appears to involve inhibition by dephosphorylated phospholamban. Phosphorylation of phospholamban relieves this inhibition. Recently, there has been a report that the cytoplasmic domain (amino acids 1-25) of phospholamban is insufficient to inhibit the $Ca^{2+}$ pump. To explore the domains of phospholamban responsible for $Ca^{2+}-ATPase$ inhibitory activity, we examined the effect of a synthetic phospholamban peptide consisting of amino acid residues 1-25 on $Ca^{2+}$ uptake by reconstituted skeletal SR $Ca^{2+}-ATPase$. The $Ca^{2+}-ATPase$ of skeletal SR was purified and reconstituted in proteoliposomes containing phosphatidylcholine (PC) or phosphatidylcholine: phosphatidylserine (PC:PS). Inclusion of a phospholamban peptide in PC proteoliposomes was associated with significant inhibition of the initial rates of $Ca^{2+}$ uptake at pCa 6.0, and phosphorylation of this peptide by the catalytic subunit of cAMP-dependent protein kinase reversed the inhibitory effect on the $Ca^{2+}$ pump. Similar effects of phospholamban peptide were also observed using PC:PS proteoliposomes. Based on these results, we could conclude that the cytoplasmic domain of phospholamban, containing the phosphorylation sites, by itself is sufficient to inhibit the $Ca^{2+}$ pump of SR.

• The Korean Journal of Physiology
• /
• v.20 no.2
• /
• pp.257-270
• /
• 1986

It has been reported that the luteal function may be regulated by the intracellular calcium in luteal cells (Higuchi et al, 1976; Dorflinger et at, 1984; Gore and Behrman, 1984) which is adjusted partially by $Ca^{++}-ATPase$ activities in luteal cell membranes (Verma and Pennistion, 1981). However, the physicochemical and kinetic properties of $Ca^{++}-ATPase$ in luteal membranes were not fully characterized. This study was, therefore, undertaken to partially characterize the physicochemical and kinetic properties of $Ca^{++}-ATPase$ system in luteal membranes and microsomal fractions, known as an one of the major $Ca^{++}$ storge sites (Moore and Pastan, 1978), from the highly luteinized ovary Highly luteinized ovaries were obtained from PMSG-hCG injected immautre female rats. Light membrane and heavy membrane fractions and microsomal fractions were prepared by the differential and discontinuous sucrose density gradient centrifugation method desribed by Bramley and Ryan (1980). Light membrane and heavy membrane fractions and microsomal fractions from highly luteinized ovaries are composed of the two different kinds of $Ca^{++}-ATPase$ system. One is the high affinity $Ca^{++}-ATPase$ which is activated in low $Ca^{++}$ concentration (Km, 10-30 nM), the other is low affinity $Ca^{++}-ATPase$ activated in higher $Ca^{++}$ concentration $(K_{1/2},\;40\;{\mu}M)$. At certain $Ca^{++}$ concentrations, activities of high and low affinity $Ca^{++}-ATPase$ are the highest in light membrane fractions and are the lowest in microsomal fractions. It appeares that high affinity $Ca^{++}-ATPase$ system have 2 binding sites for ATP (Hill's coefficient; around 2 in all membrane fractions measured) and the positive cooperativity of ATP bindings obviously existed in each membrane fractions. The optimum pH for high affinity $Ca^{++}-ATPase$ activation is around S in all membrane fractions measured. The lipid phase transition temperature measured by Arrhenius plots of high affinity $Ca^{++}-ATPase$ activity is around $25^{\circ}C$. The activation energies of high affinity $Ca^{++}-ATPase$ below the transition temperature are similar in each membrane fractions, but at the above transition temperature, it is the hightest in heavy membrane fractions and the lowest in microsomal fractions. According to the above results, it is suggested that intracellular $Ca^{++}$ level, which may regulate the luteal function, may be adjusted primarily by the high affinity $Ca^{++}-ATPase$ system activated in intracellular $Ca^{++}$ concentration range $(below\;0.1\;{\mu}M)$.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.9 no.1
• /
• pp.45-50
• /
• 1980

Myofibrilar Protein from Korean Duck Muscle was extracted and ATPase activities were studied. The results were as follows: 1. Mg-activated ATPase activity of Myofibril from Korean Duck, muscle exhibited a biphasic response, ATPase activity was high at a low ionic strength and low activity was showed at high ionic strength. 2. Effect of EDTA on the Myofibrillar protein ATPase activity was studied, it was investigated that the EDTA inhibition was showed at the concentration of $6.9{\mu}g$ and it above. 3. It showed that the effect of Ca++ on ATPase activity was decreased at the lower than $3{\mu}g$. Inhibition showed at the concentration of $6.9{\mu}g$ and it above. 4. It showed that the effect of Mg++ on ATPase activity was decreased at the lower than $3.6{\mu}g$. Inhibition showed at the concentration of $3.9{\mu}g$ and it above.