[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. Sedimentation experiments showed that F-protein binds to myosin and myosin rod rather than to light meromyosin or S-1. The F-protein binding to myosin and rod is of a similar character. The calculated values of the constants of F-protein binding to myosin and rod are 2.6 X 10(5) M-1 and 2.1 X 10(5) M-1, respectively. The binding sites are probably located on the subfragment-2 portion of the myosin molecule. The number of F-protein binding sites on myosin calculated per chain weight of 80 000 is 5 +/- 1. The sedimentation results were confirmed by electron microscopic data. F-protein does not bind to light meromyosin paracrystals, but decorates myosin and rod filaments with the interval of 14.3 nm regardless of whether F-protein is added before or after filamentogenesis. A comparison of optical diffraction patterns obtained from myosin and rod filaments with those from decorated ones revealed a marked enhancement of meridional reflection at (14.3 nm)-1 in the latter case.
D000818:Animals; D001665:Binding Sites; D066298:In Vitro Techniques; D007700:Kinetics; D008854:Microscopy, Electron; D009132:Muscles / Q000201:enzymology / Q000378:metabolism / Q000648:ultrastructure; D009218:Myosins / Q000378:metabolism*; D010732:Phosphofructokinase-1 / Q000378:metabolism*; D011817:Rabbits
D010732:Phosphofructokinase-1; D009218:Myosins
Opredelenie kolichestvennykh parametrov sviazyvaniia F-belka (fosfofruktokinazy) s miozinom i lokalizatsiia uchastkov sviazyvaniia na miozinovoĭ molekule.