Inhibition of Na+, K+-ATPase in the presence of crown ethers: modulation of ionic composition or pharmacological effects
| Autor: | A. Cruz e Carvalho, O. V. Krasilnikov, L. N. Yuldasheva |
|---|---|
| Rok vydání: | 2007 |
| Předmět: |
chemistry.chemical_classification
biology Stereochemistry ATPase 18-Crown-6 General Chemistry Condensed Matter Physics Michaelis–Menten kinetics Dissociation constant chemistry.chemical_compound stomatognathic system chemistry ATP hydrolysis biology.protein Na+/K+-ATPase Ion transporter Crown ether Food Science |
| Zdroj: | Journal of Inclusion Phenomena and Macrocyclic Chemistry. 60:65-70 |
| ISSN: | 1573-1111 0923-0750 |
| DOI: | 10.1007/s10847-007-9353-9 |
| Popis: | It is believed that the biological effects of chelating agents such as crown ethers are largely related to their ability to form complexes with ions and/or to facilitate ion transport across membranes. Specific influences are rarely related. Here we present the evidence that even one of the simplest representatives of the crown ether super-family, 1,4,7,10,13,16-hexaoxacyclooctane (18-crown-6), is able to affect the activity of Na+, K+-ATPase directly. Using nonlinear regression fitting to kinetic data we have found that the crown ether diminishes the apparent Michaelis constant, K m , and the maximal rate of ATP hydrolysis, V m , acting as noncompetitive inhibitors. The apparent dissociation constants, K i , for the crown interaction with the free ATPase and with the enzyme-substrate complex were established to be of 77 ± 3 mM and 21 ± 2 mM, respectively. So 18-crown-6 possesses weak but “direct” pharmacological activity on Na+, K+-ATPase hinders the formation of enzyme–substrate complex and detains the enzyme in this state. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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