title: N-ethylmaleimide-modified heavy meromyosin. A probe for actomyosin interactions.
abstract: Treatment of rabbit skeletal muscle heavy meromyosin (HMM) with the sulfhydryl reagent N-ethylmaleimide (NEM) produces a species of HMM which remains tightly bound to actin in the presence of MgATP. NEM-HMM forms characteristic "arrowhead" complexes with actin which persist despite rinses with MgATP. NEM-HMM inhibits the actin activation of native HMM-ATPase activity, the superprecipitation of actomyosin, the contraction of glycerinated muscle myofibrils, and the contraction of cytoplasmic strands of the soil amoeba Chaos carolinensis. However, NEM-HMM does not interfere with in vitro microtubule polymerization or beating of demembranated cilia.
mesh_terms: D000199:Actins / Q000378:metabolism; D000205:Actomyosin / Q000378:metabolism*; D000251:Adenosine Triphosphatases / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000656:Amoeba / Q000187:drug effects / Q000502:physiology; D000818:Animals; D005033:Ethylmaleimide / Q000494:pharmacology*; D009210:Myofibrils / Q000502:physiology / Q000648:ultrastructure; D015879:Myosin Subfragments / Q000378:metabolism* / Q000494:pharmacology; D011485:Protein Binding; D011817:Rabbits
chemical_list: D000199:Actins; D015879:Myosin Subfragments; D000255:Adenosine Triphosphate; D000205:Actomyosin; D000251:Adenosine Triphosphatases; D005033:Ethylmaleimide