Т. О. Veklich¹, О. V. Bevza¹, О. V. Maliuk¹*, S. О. Kosterin¹,
R. V. Rodik², S. H. Vyshnevskyi², V. І. Kalchenko²

¹Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv;
*e-mail: alexmaliukid@gmail.com;
²Institute of Organic Chemistry, National Academy of Sciences of Ukraine

Received: 05 November 2023; Revised: 04 January 2024;
Accepted: 01 February 2024; Available on-line: 26 February 2024

The experiments with the suspension of plasma membranes of myometrium cells, treated with 0.1% digitonin solution, were used to study kinetic regularities of the inhibitory effect of tetra-N-phenylsulfonyl trifluoroacetamidine-thiacalixarene (С-1087) on the activity of Са²⁺,Mg²⁺-ATPase. The studies demonstrated the impact of C-1087 on the cumulative effect and the maximal velocity of ATP hydrolysis. No effect of С-1087 on the affinity between Са²⁺,Mg²⁺-ATPase, and АТР, affinity and cumulative effect of Ca ions and activation coefficient for Mg ions was revealed. A considerable decrease in the maximal velocity of ATP hydrolysis evidenced a complete non-competitive mechanism of inhibiting Са²⁺,Mg²⁺-АТРase activity with thiacalix[4]arene С-1087. Computer simulation demonstrated that thiacalix[4]arene С-1087 inhibiting effect on Са²⁺,Mg²⁺-ATPase may be conditioned by the cumulative effect of four spatially oriented N-sulfonylamidine groups on the upper rim of its macrocyclic platform.