title: Dynamic laser light scattering of papain-treated thick filaments from limulus striated muscle in suspension.
abstract: Using quasielastic light scattering we have previously shown an increase in high frequency internal motion of isolated thick filament upon activation. This we have attributed to cross-bridge motion. Here we show that after cleavage of the S1 moiety of myosin from isolated filaments with papain, calcium ions no longer activate the isolated filaments to produce high-frequency motions.
mesh_terms: D000818:Animals; D006737:Horseshoe Crabs; D066298:In Vitro Techniques; D007834:Lasers; D009119:Muscle Contraction / Q000187:drug effects*; D009132:Muscles / Q000187:drug effects / Q000502:physiology* / Q000648:ultrastructure; D009210:Myofibrils / Q000187:drug effects / Q000502:physiology* / Q000648:ultrastructure; D015879:Myosin Subfragments; D009218:Myosins / Q000378:metabolism; D010206:Papain / Q000494:pharmacology*; D010446:Peptide Fragments / Q000378:metabolism; D012542:Scattering, Radiation
chemical_list: D015879:Myosin Subfragments; D010446:Peptide Fragments; D010206:Papain; D009218:Myosins