Document Detail

The ATPase kinetics of insect fibrillar flight muscle myosin subfragment-1.
MedLine Citation:
PMID:  2940261     Owner:  NLM     Status:  MEDLINE    
Myosin subfragment-1 (S1) has been prepared from the fibrillar flight muscles of the giant water bug Lethocerus by chymotryptic digestion of myofibrillar suspensions in the absence of magnesium ions. The S1 obtained has a single light chain and a heavy chain with molecular weights of about 18 kDa and 90 kDa respectively. The kinetics of the elementary steps of the magnesium-dependent ATPase of insect S1 and rabbit S1 are similar, both with ATP and with ATP analogues as substrates. However, the presence of variable amounts of inactive protein within our preparation means that several rate constants cannot be obtained with as much precision in the case of insect S1. The most striking differences between the rabbit and insect S1 are values for the Vmax and the Km of actin during actin-activation of the MgATPase activity, which are up to an order of magnitude lower and greater in the insect than in the rabbit, respectively. The mechanical properties of strain activation and of capacity to do extended oscillatory work are unique to insect fibrillar flight muscle and distinguish it from vertebrate striated muscle. It is likely that these properties reflect differences in the organization of actin and myosin within the respective filament lattices rather than intrinsic differences in the ATPase mechanisms of the isolated myosin molecules from the two types of muscle.
D C White; R W Zimmerman; D R Trentham
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of muscle research and cell motility     Volume:  7     ISSN:  0142-4319     ISO Abbreviation:  J. Muscle Res. Cell. Motil.     Publication Date:  1986 Apr 
Date Detail:
Created Date:  1986-06-30     Completed Date:  1986-06-30     Revised Date:  2009-11-19    
Medline Journal Info:
Nlm Unique ID:  8006298     Medline TA:  J Muscle Res Cell Motil     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  179-92     Citation Subset:  IM    
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MeSH Terms
Actomyosin / metabolism
Adenosine Diphosphate / metabolism
Adenosine Triphosphatases / analysis*
Adenosine Triphosphate / metabolism
Formycins / metabolism
Guanosine Triphosphate / analogs & derivatives,  metabolism
Molecular Weight
Myofibrils / analysis
Myosin Subfragments
Myosins / analysis*,  metabolism
Peptide Fragments / analysis*,  metabolism
Ribonucleotides / metabolism
Thionucleotides / metabolism
Reg. No./Substance:
0/Formycins; 0/Myosin Subfragments; 0/Peptide Fragments; 0/Ribonucleotides; 0/Suspensions; 0/Thionucleotides; 16409-13-5/formycin triphosphate; 17670-19-8/6-thioguanosine 5'-triphosphate; 27652-34-2/6-thioinosine-5'-triphosphate; 56-65-5/Adenosine Triphosphate; 58-64-0/Adenosine Diphosphate; 86-01-1/Guanosine Triphosphate; 9013-26-7/Actomyosin; EC 3.6.1.-/Adenosine Triphosphatases; EC

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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