Suppression of crossbridge motions of isolated thick myofilaments in ATP-free medium by thiourea.
Thiourea is known to suppress the contractile response of Mytilus anterior byssus retractor muscle and toad sartorious muscle following electrical or chemical stimulation without abolishing of the electrical responses. In addition, it blocks the shortening of glycerinated sartorious muscle induced by Ca2+. With dynamic laser light scattering method we found that thiourea suppresses the increase of the average linewidth of the photoelectron count autocorrelation function, gamma, of isolated thick filaments of Limulus striated muscle induced by depletion of ATP. The results obtained suggest that thiourea prevents the crossbridges from moving away from the thick myofilament backbones which will, in turn, prohibit the crossbridges from interacting with the thin myofilaments.
Fan
S F
SF
Department of Physiology and Biophysics, State University of New York, Stony Brook 11794.
Dewey
M M
MM
Chu
B
B
D000255:Adenosine Triphosphate / Q000494:pharmacology*; D000818:Animals; D002118:Calcium / Q000494:pharmacology; D006737:Horseshoe Crabs; D066298:In Vitro Techniques; D007700:Kinetics; D009119:Muscle Contraction / Q000187:drug effects; D009132:Muscles / Q000187:drug effects / Q000502:physiology* / Q000648:ultrastructure; D013890:Thiourea / Q000494:pharmacology*
D000255:Adenosine Triphosphate; D013890:Thiourea; D002118:Calcium