[Effect of polyamines on actomyosine-ATP-ase activity in smooth muscles of the uterus].

The ability of the aliphatic polyamines to inhibit [figure: see text] the ATPase activity of smooth muscle actomyosine satisfies the succession: spermine > spermidine > putrescine that is correlated with magnitude of positive charge at physiological value of pH. The most effective inhibitor of the ATP hydrolysis process is the spermine, which highest inhibitory action is manifested at 10(-3) M concentration, in lesser concentration (10(-5) M) activates the actomyosine ATPase. While defining the kinetic parameters of the ATP hydrolysis reaction catalyzed by uterus myometrium the correlation between inhibiting the ATPase activity of myometrium contractile complex under introduction into the incubation medium of 10(-3) M spermine and decreasing the affinity of actomyosine for ATP was made; the activating effect of spermine on ATPase activity of actomyosine complex in the presence of 10(-5) M spermine correlated with the increase of actomyosine affinity for Mg2+.