Calix[4]arene C-90 Selectively Inhibits Ca²⁺,Mg²⁺-ATPase of Myometrium Cell Plasma Membrane

---

T. A. Veklich^1*, A. A. Shkrabak¹, N. N. Slinchenko^1#, I. I. Mazur¹, R. V. Rodik², V. I. Boyko², V. I. Kalchenko², and S. A. Kosterin¹

¹Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Leontovicha str. 9, 01601 Kiev, Ukraine; fax: +38 (044) 279-6365; E-mail: veklich@biochem.kiev.ua

²Institute of Organic Chemistry, National Academy of Sciences of Ukraine, Murmanskaya str. 5, 02660 Kiev, Ukraine; fax: +38 (044) 573-2643; E-mail: vik@ioch.kiev.ua

^* To whom correspondence should be addressed.

^# Deceased.

Received November 19, 2013; Revision received January 31, 2014

---

The supramolecular compound calix[4]arene C-90 (5,11,17,23-tetra(trifluoro)methyl(phenylsulfonylimino)-methylamino-25,26,27,28-tetrapropoxycalix[4]arene) is shown to efficiently inhibit the ATP hydrolase activity of Ca²⁺,Mg²⁺-ATPase in the myometrium cell plasma membrane fraction and also in a preparation of the purified enzyme solubilized from this subcellular fraction. The inhibition coefficient I_0.5 values were 20.2 ± 0.5 and 58.5 ± 6.4 µM for the membrane fraction and the solubilized enzyme, respectively. The inhibitory effect of calix[4]arene C-90 was selective comparatively to other ATPases localized in the plasma membrane: calix[4]arene C-90 did not influence the activities of Na⁺,K⁺-ATPase and “basal” Mg²⁺-ATPase. The inhibitory effect of calix[4]arene C-90 on the Ca²⁺,Mg²⁺-ATPase activity was associated with the cooperative action of four trifluoromethylphenylsulfonylimine (sulfonylamidine) groups oriented similarly on the upper rim of the calix[4]arene macrocycle (the calix[4]arene “bowl”). The experimental findings seem to be of importance for studies, using calix[4]arene C-90, of membrane mechanisms of regulation of calcium homeostasis in smooth muscle cells and also for investigation of the participation of the plasma membrane Ca²⁺-pump in control of electro- and pharmacomechanical coupling in myocytes.

---

KEY WORDS: Ca²⁺,Mg²⁺-ATPase, plasma membrane calcium pump, smooth muscle cells, myometrium, calix[4]arenes, sulfonylamidines

DOI: 10.1134/S0006297914050058

---