[Role of light chains of myosin in the regulation of contraction of vertebrate striated muscles].

The data of the study on Ca2+ sensitivity of ATPase activity of myosin from vertebrate striated muscles in the presence of actin and the conditions of its manifestation and disappearance are presented. The role of Ca2+ sensitivity of actin-activated myosin ATPase in the regulation of contraction of vertebrate striated muscles is discussed.

[Structural changes in actin filaments during binding with phosphofructokinase (F-protein), detected using an optical diffraction method].

It has been previously shown by us that phosphofructokinase (F-protein) binds to rabbit skeletal muscle F-actin and reconstituted thin filaments forming ordered bundles. Upon low molar ratios of phosphofructokinase to actin in the complex bundles the enzyme molecules are arranged between actin filaments regularly in the form of crossbridges. The increase of phosphofructokinase: actin ratio up to equimolar one and more leads to the filling of the space between actin filaments with phosphofructokinase-molecules.

[Binding of F-protein (phosphofructokinase) to F-actin].

By the use of sedimentation method the interaction of F-protein (phosphofructokinase) with F-actin has been studied in 0.1 M KCl, 10 mM K-phosphate buffer, pH 6.5.

[Determination of quantitative parameters of the binding of F-protein (phosphofructokinase) with myosin and localization of binding sites on the myosin molecule].

To determine the localization of F-protein binding sites on myosin, the interaction of F-protein with myosin and its proteolytic fragments in 0.1 M KCl, 10 mM K-phosphate pH 6.5 was studied, using sedimentation, electron microscopic and optical diffraction methods.

[Electron microscopy study of the interaction of F-protein (phosphofructokinase) with actin-containing filaments].

By the use of electron microscopy and optical diffraction the interaction of F-protein (phosphofructokinase) with F-actin and reconstructed thin filaments has been revealed. F-protein distributes itself along the filament bundles at regular intervals of 36-38 nm.