Cyclopiazonic acid reduces the coupling factor of the Ca2+‐ATPase acting on Ca2+ binding
- 11 September 2004
- journal article
- Published by Wiley in FEBS Letters
- Vol. 576 (1-2) , 73-76
- https://doi.org/10.1016/j.febslet.2004.08.064
Abstract
The mycotoxin cyclopiazonic acid (CPA) is a potent inhibitor of the sarcoplasmic reticulum Ca2+-ATPase. The compound decreases the affinity of the Ca2+-ATPase for Ca2+ and reduces the maximum specific activity of the enzyme. Furthermore, CPA abolishes the cooperativity of Ca2+ transport, showing a Ca2+/ATP ratio ∼1 at any extent of Ca2+ saturation. There is also an effect on the Ca2+-binding mechanism, where the addition of CPA results in binding of only half-maximal amount of Ca2+ observed in its absence. The experimental data suggest that in the presence of CPA, only a single Ca2+ ion binds to the Ca2+-ATPaseKeywords
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