title: Some characteristics of beta-naphthyl triphosphate as a substrate of heavy meromyosin. F-actin-inactivated hydrolysis showing initial burst.
abstract: The initial burst of Pi liberation was found in the hydrolysis of beta-naphthyl triphosphate (beta-NapP3) by heavy meromyosin (HMM) in the presence of Mg ions as well as in the hydrolysis of ATP. However, unlike that of ATP, the steady-state hydrolysis of beta-NapP3 by HMM was inhibited by the addition of F-actin to the reaction solution. Although the possession of an initial burst-like property during interaction of a substrate and myosin is believed by many investigators to be a key factor in F-actin activation of substrate hydrolysis in vitro and in the molecular mechanism of muscle contraction, the above results suggest that this is not generally true. beta-NaP3 did not induce superprecipitation of actomyosin solution and suppressed ATP-induced superprecipitation.
mesh_terms: D000199:Actins / Q000494:pharmacology*; D000255:Adenosine Triphosphate / Q000378:metabolism; D011232:Chemical Precipitation; D006868:Hydrolysis; D007700:Kinetics; D008274:Magnesium / Q000494:pharmacology; D015879:Myosin Subfragments / Q000378:metabolism*; D009284:Naphthols / Q000378:metabolism*; D009943:Organophosphorus Compounds / Q000378:metabolism*
chemical_list: D000199:Actins; D015879:Myosin Subfragments; D009284:Naphthols; D009943:Organophosphorus Compounds; D000255:Adenosine Triphosphate; D008274:Magnesium