Binding of muscle tropomyosin to muscle F-actin at an 8.4/1.0 molar ratio protects 58% of the F-actin from depolymerization by actin-depolymerizing factor for at least 3 hours.
Does tropomyosin binding to F-actin protect it from depolymerization by actin-depolymerizing factor in vitro?
Tropomyosin binding specifically protects F-actin filaments from disassembly by actin-depolymerizing factor in vitro.
Brain or muscle F-actin is rapidly depolymerized to monomeric actin in vitro by actin-depolymerizing factor, a protein isolated from chick embryo brain. Binding of muscle tropomyosin to muscle F-actin protects the F-actin from depolymerization by this factor. A 8.4/1.0 molar ratio of actin subunits to tropomyosin, achieved by incubation of the F-actin with excess tropomyosin, protects 58% of the F-actin from depolymerization by excess actin-depolymerizing factor for at least 3 hr at 25 degrees C. Thus, actin-depolymerizing factor seems to be specifically directed toward actin filaments lacking tropomyosin.
Bernstein et al. (Fri,) reported a other. Tropomyosin binding to F-actin vs. F-actin lacking tropomyosin was evaluated on Protection from depolymerization by excess actin-depolymerizing factor. Binding of muscle tropomyosin to muscle F-actin at an 8.4/1.0 molar ratio protects 58% of the F-actin from depolymerization by actin-depolymerizing factor for at least 3 hours.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: