Journal archive > 2009 > N 6 November-December
A. A. Bevza1, R. D. Labyntseva1, R.V.Rodik2, S. O. Cherenok2, S. O.Kosterin1, V.I.Kalchenko2
1Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv;
2Institute of Organic Chemistry, National Academy of Sciences of Ukraine, Kyiv;
We studied the effect of calixarenеs C-97, C-99 and C-107 (codes are shown) functionalized by: one fragment of methylene-bisphosphonic, two fragments of hydroxy-phosphonic and two fragments of amino(methyl)phosphonic acids, respectively, on the enzymatic activity of actomyosin ATPase and ATPase of subfragment-1 (head) of myosin from smooth muscle of the uterus.
It has been shown that calixarene C-107 at a concentration of 100 µM activated enzymatic activity of actomyosin ATPase by 230 ± 12% (the value of the apparent constant of activation A0.5?=?9.6?±?0.7 µM). At the same time, 100 µM calixarenes C-97 and C-99 inhibited the activity by 70 ± 8% and 50 ± 9%, respectively (the value of the apparent constants of inhibition being I0.5?=?84.0?±?2.0 and 98.8?± 1.3 µM). In the experiments carried out with the myosin subfragmen-1 ATPase it was shown that 100 µM calixarene C-107 increased ATP hydrolysis more than twice (A0.5 =?25?± 4?µM) and 100 µM calixarene C-99 inhibited activity by 77 ± 4% (I0.5 = 43 ±?8?µM).
Photon correlation spectroscopy has shown an increase of average hydrodynamic diameters (Dav) of subfragment-1 in the presence of calixarene C 107. This correlates with an increase of calixarene concentration. In addition, in the presence of calixarene C-107 one could observe a time-dependent increase of Dav in the smooth muscle myosin head.
The data presented demonstrates that the calixarenes which we have studied, can influence uterus smooth muscle at the level of the contractile proteins, namely the ATPase of the catalytic domain of the myosin head.
Key words: actomyosin, subfragment-1 of myosin, calixarenеs, smooth muscle, myometrium, enzymic hydrolysis of АТР, kinetic properties of АТРаse.
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