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Journal archive > 2008 > N 4 July-August

SPERMINE EFFECT ON KINETIC CHARACTERISTICS OF АТР HYDROLASE
SYSTEMS OF UTERUS MYOCYTE PLASMA MEMBRANE

T. O. Veklich, O. A. Shkrabak, S. O. Kosterin

Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv;
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The paper deals with the activation effect of aliphatic polyamine spermine (1 mM) on the enzymatic activity of ouabain-sensitive Nа+,K+-АТРase and the ouabain-resistant basal Mg2+-АТРase in the suspension of the myometrium cell plasma membranes treated with 0.1% digitonin solution. It was found that spermine increased the enzymatic Na+,K+-АТРase activity without disrupting of its dome-shaped dependence on the ratio of [Na+]/[K+] in isotonic condition. The constants of the enzyme activation by Na+ and K+ ions did not vary. Spermine also did not change the character of dependence of Nа+,K+-АТРase and Mg2+-АТРase activity on the concentration of MgCl2 (0.1–2 mM) and on the concentration of ATP (0.05–1 mM). In this case the affinity for the corresponding compounds did not also vary. Thus, the activation by spermine occurred mainly due to enlargment of enzyme «turnover number» according to Vmax increase. It is expected that the obtained experimentall data can be important for further investigations of regulation mechanisms of Nа+,K+-АТРase and Mg2+-АТРase activity and also mechanisms of cations exchange control in the smooth muscles.

Key words: polyamines, spermine, Nа+,K+-АТРase, Mg2+-АТРase, plasmatic membrane, smooth muscle cells, myometrium, enzymatic hydrolysis of АТР, kinetic properties of АТРase.

The original article in Ukrainian is available for download in PDF format.

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