Effect of liver plasma membranes on G-actin. II. Fate of actin-bound nucleotide

Abstract

G-actin incubated in presence of a liver fraction enriched in plasma membranes rapidly denatures, as evidenced by the biphasic loss of polymerizability and DNase inhibition. The inactivation is shown to result from the loss of actin-bound nucleotide induced by the rapid destruction of free nucleotides by membrane NPases. This is further supported by the observation that addition of either ATP or ADP to actin that has been exposed to membranes completely stops the denaturation process and partly restores polymerizing capacity. The biphasic aspect of inactivation is explained by the protective action of AMP and (or) adenosine formed in the course of the incubation.