Tag Archives: kinetic properties of ATPase
The calixarene C-107 increases the affinity of the Na(+),K(+)-АТРase activity in plasmatic membrane of smooth muscle cells to the ouabain
T. O. Veklich1, A. A. Shkrabak1, R. V. Rodik2,
V. I. Kalchenko2, S. O. Kosterin1
1Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv;
e-mail: kinet@biochem.kiev.ua;
2Institute of Organic Chemistry, National Academy of Sciences of Ukraine, Kyiv;
e-mail: vik@ioch.kiev.ua
In the experiments carried out with the suspension of the myometrium cell plasmatic membranes treated with 0.1% digitonin solution we investigated the influence of сalixarene С-107 (5,17-diamino(2-pyridyl)methylphosphono-11,23-di-tret-butyl-26,28-dihydroxy-25,27-dipropoxycalix[4]arene) on the Nа+,K+-АТРase activity. It was shown that this calixarene increased the affinity of the enzyme for the sodium pump conventional inhibitor – ouabain: the magnitudes of the seeming constant of inhibition I0.5 changed from 26.9 ± 1.3 mM to 10.9 ± 0.6 mM. However the ouabain itself did not influence on the affinity of the Nа+,K+-АТРase for сalixarene С-107.
Comparative investigation of the effect of calix[4]arene C-99 and its analogs on Nа(+),K(+)-ATPase activity of uterus myocite plasma membrane
T. O. Veklich1, A. A. Shkrabak1, S. O. Cherenok2,
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
The aim of our investigation was to determine structural features of calix[4]arene C-99 which are important for its inhibition properties relative to Nа+,K+-ATPase of uterus myocite plasma membrane. Therefore we studied the effect of calix[4]-arenes С-296, С-297, С-424, С-425, С-426, С-427, which are structurally similar to this inhibitor, on the mentioned enzyme activity. We have shown that calixarenes С-296 and С-297 which have two additional propoxy groups on the lower rim of macrocycle are less effective inhibitors of Nа+,K+-ATPase relative to calixarene C-99. Calixarenes С-425 and С-427 which have on the upper rim of macrocycle three and four phosponic residues, respectively, also inhibit Nа+,K+-ATPase activity less effectively as compared to calixarene C-99. Both calixarenes: С-424, which has only two carbonate residues on the upper rim, and С-426, which has on the upper rim ketomethilphosphonate residues instead of hydroxymethilphosphonate residues of calixarene C-99, do not affect Nа+,K+-ATPase activity. We have made respective conclusions concerning the role of certain chemical groups of calixarene C-99 during its interaction with Nа+,K+-ATPase.
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.