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Zebrafish Xenograft Model for Predicting Cisplatin Efficacy in Muscle-Invasive Bladder Cancer
tInhibition of actin-activated myosin Mg2+-ATPase in smooth muscle by ruthenium red.
1992/12/07
Nakamura F, Naka M, Tanaka T.
FEBS Lett. 1992 Dec 7;314(1):93-6.
Abstract
Ruthenium red was found to inhibit actin-activated myosin Mg(2+)-ATPase in smooth muscle and to bind to myosin heavy chain, but not to F-actin. The inhibition by Ruthenium red of actin-activated Mg(2+)-ATPase was of the competitive type with respect to actin (Ki 4.4 microM) and of the non-competitive type with respect to ATP (Ki 6.6 microM). However, Ruthenium red scarcely dissociated the acto-heavy meromyosin complex during the ATPase reaction. These results suggest that Ruthenium red interacts directly with the binding site for F-actin on the myosin heavy chain. This site is considered to be necessary not for maintaining the binding affinity of myosin for F-actin, but for activation of the Mg(2+)-ATPase.