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.

Keywords: aminophosphonic acids, calixarenes, kinetic properties of ATPase, Mg(2+)-ATPase­, myometrium, Na(+)-K(+)-ATPase, plasma membrane, smooth muscle cells