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;
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 calixarene C-90 (5,11,17,23-tetra(trifluor)methyl(phenylsulphonylimino)-methylamino-25,26,27,28-tetra propoxi-calixarene) on the Ca2+,Mg2+-ATPase activity (the magnitude of І0.5 was 20.2 ± 0.5 mkM). The inhibitory action of calixarene 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-arene base rather than with the action of tetraphenol macrocycle or separate pharmacophore sulphonilamidin groups. Considering established kinetic pattern of calixarene 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 calixarene C-90.
Key words: Ca2+,Mg2+-ATPase, plasma membrane, smooth muscle cells, myometrium, enzymatic hydrolysis of ATP, kinetic properties of ATPase, calixarenes.
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