Tag Archives: Ca(2+)-Mg(2+)-ATPase
Calix[4]arene С-956 selectively inhibits plasma membrane Са(2+),Mg(2+)-АТРase in myometrial cells
Т. O. Veklich1, O. A. Skrabak1, Yu. V. Nikonishyna1, R. V. Rodik2, V. I. Kalchenko2, S. O. Kosterin1
1Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv;
2Institute of Organic Chemistry, National Academy of Sciences of Ukraine, Kyiv;
e-mail: veklich@biochem.kiev.ua; manli@ioch.kiev.ua
Using enzymatic assays and kinetic analysis, we demonstrated that 100 µM calix[4]arene C-956 (5,11,17,23-tetra(trifluoro)methyl-(phenylsulfonylimino) methylamino-25,27-dioctyloxy-26,28-dipropoxycalix[4]arene) had the most significant inhibitory effect on the plasma membrane Са2+,Mg2+-АТРase activity compared to effects of other calix[4]arenes, and had no effect on specific activities of other membrane ATPases. Using confocal microscopy and fluorescent probe fluo-4, we observed an increase of the intracellular level of Ca2+ after application of calix[4]arene C-956 to immobilized myocytes. Analysis of the effect of calix[4]arene C-956 on the hydrodynamic diameter of myocytes demonstrated that application of calix[4]arene C-956 solution decreased this parameter by 45.5 ± 9.4% compared to control value similarly to the action of uterotonic drug oxytocin.
Characteristics of Ca(2+), Mg(2+)-ATPases of peripheral blood lymphocytes of patients with rheumatic pathology
R. V. Fafula, U. P. Efremova, Z. D. Vorobets
Danylo Halytski Lviv National Medical University, Ukraine;
e-mail: roman_fafula@ukr.net, vorobets@meduniv.lviv.ua
The analysis of the kinetic properties of Ca2+, Mg2+-ATPase of saponin-perforated peripheral blood lymphocytes of donors and patients with rheumatoid arthritis and ankylosing spondylitis was carried out. When analyzing the alterations in hydrolase activity of Ca2+, Mg2+-ATPase it was shown that affinity of Ca2+, Mg2+-ATPase of plasma membrane and membranes of endoplasmic reticulum for ATP do not significantly differ. It was found that the inhibition of examined enzyme systems occurs by mixed type both due to the reduction of maximum reaction rate and to the decrease of Ca2+, Mg2+-ATPase affinity for ATP in conditions of rheumatic pathology in the immunocompetent cells. It was identified that Ca2+, Mg2+-ATPase had significantly lower affinity for Ca2+ in lymphocytes of persons with rheumatic disorders than in donors.
The inhibitory influence of calix[4]arene of C-90 on the activity of Ca(2+),Mg(2+)-ATPases in plasma membrane and sarcoplasmic reticulum in myometrium сells
T. O. Veklich
Palladin Institute of Biochemistry,National Academy of Sciences of Ukraine, Kyiv;
e-mail: veklich@biochem.kiev.ua
Our study on the plasma membrane vesicles and myometrium cells treated with 0.1% digitonin showed that inhibitory effect of calix[4]arene C-90 (5,11,17,23-tetra(trifluoro)methyl(phenylsulphonylimino)-methylamino-25,26,27,28-tetrapropoxy-calix[4]arene) on the plasma membrane Ca2+,Mg2+-ATPase was more significant than on the Ca2+,Mg2+-ATPase in sarcoplasmic reticulum (the inhibition coefficient I0.5 values were 20.2 ± 0.5 µM and 57.0 ± 1.4 µM for the plasma membrane Ca2+,Mg2+-ATPase and Ca2+,Mg2+-ATPase in sarcoplasmic reticulum, respectively (n = 5)). Inhibition kinetics of calix[4]arene C-90 effect on the Ca2+,Mg2+-ATPase activities in plasma membrane and sarcoplasmic reticulum were studied. This substance inhibited both pumps as complete noncompetitive inhibitor. Calix[4]arene C-90 caused the increase of intracellular Ca2+ concentration and decrease of hydrodynamic diameter in smooth muscle cells similar to the action of uterotonic drug oxytocin.
Kinetic regularities of calixarene C-90 action on the myometrial plasma membrane Ca(2+),Mg(2+)-ATPase activity and on the Ca(2+) concentration in unexcited сells of the myometrium
T. O. Veklich1, A. A. Shkrabak1, Yu. Yu. Mazur1, R. V. Rodik2,
V. I. Boyko2, V. I. Kalchenko2, S. O. Kosterin1
1Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv;
2Institute of Organic Chemistry, National Academy of Sciences of Ukraine, Kyiv;
e-mail: kinet@biochem.kiev.ua; vik@ioch.kiev.ua
Plasma membrane Ca2+,Mg2+-ATPase is an important element of general myometrium tonus control mechanism, which also makes a contribution to muscle tension relaxation after its contraction. Expiriments were done on the myometrial cell plasma membrane suspension, which was treated with 0.1% digitonin solution. The authors have investigated the inhibitory action of calix[4]arene C-90 (5,11,17,23-tetra(trifluor)methyl(phenylsulphonylimino)-methylamino-25,26,27,28-tetra propoxi-calix[4]arene) on the Ca2+,Mg2+-ATPase activity (the magnitude of І0.5 was 20.2 ± 0.5 mkM). The inhibitory action of calix[4]arene C-90 on the activity of Ca2+,Mg2+-ATPase is explained as cooperative action of four trifluormethyl(phenylsulfonylimino)methylamino groups that are spatially oriented on the calix[4]-arene base rather than with the action of tetraphenol macrocycle or separate pharmacophore sulphonilamidin groups. Considering established kinetic pattern of calix[4]arene C-90 inhibitory action on the plasma membrane Ca2+,Mg2+-ATPase activity, stationary kinetical model of basal calcium concentration control in unexcited uterus myocytes was developed. It is assumed that obtained results may be promising for creation of new generation (“supramolecular”) pharmacological agent – uterus basal tonus stimulator – on the base of calix[4]arene C-90.