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rdf:type |
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lifeskim:mentions |
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pubmed:issue |
2
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pubmed:dateCreated |
1981-3-24
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pubmed:abstractText |
The regulation of vertebrate skeletal muscle contraction by the troponin . tropomyosin complex is generally thought to be the result of tropomyosin physically blocking the myosin binding site of actin in the absence of Ca2+. This mechanism was tested during steady state ATP hydrolysis by comparing the degree of association of myosin subfragment 1 (S-1) with the actin . troponin . tropomyosin complex in the absence and presence of Ca2+. Binding in the presence of ATP was determined by stopped flow absorbance measurements at 25 degrees C. Although the steady state ATPase rate was reduced 96% in the absence of Ca2+, the association constant of S-1 with regulated actin was virtually the same in the absence of Ca2+ (1.3 X 10(4) M-1) as in the presence of Ca2+ (2.3 X 10(4) M-1). The association constant of S-1 to regulated actin in the presence of Ca2+ was similar to the association constant of S-1 to unregulated actin. These results suggest that the troponin . tropomyosin complex does not inhibit the actin-activated ATPase activity by preventing the binding of S-1 . ATP or S-1 . ADP . Pi to actin; rather, it may act by blocking the release of Pi from the acto-S-1 . ADP . Pi complex.
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pubmed:grant |
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pubmed:commentsCorrections |
http://linkedlifedata.com/resource/pubmed/commentcorrection/6450206-133714,
http://linkedlifedata.com/resource/pubmed/commentcorrection/6450206-13485191,
http://linkedlifedata.com/resource/pubmed/commentcorrection/6450206-157897,
http://linkedlifedata.com/resource/pubmed/commentcorrection/6450206-158378,
http://linkedlifedata.com/resource/pubmed/commentcorrection/6450206-302333,
http://linkedlifedata.com/resource/pubmed/commentcorrection/6450206-4181952,
http://linkedlifedata.com/resource/pubmed/commentcorrection/6450206-4276966,
http://linkedlifedata.com/resource/pubmed/commentcorrection/6450206-4577547,
http://linkedlifedata.com/resource/pubmed/commentcorrection/6450206-5113,
http://linkedlifedata.com/resource/pubmed/commentcorrection/6450206-6102396,
http://linkedlifedata.com/resource/pubmed/commentcorrection/6450206-6930656,
http://linkedlifedata.com/resource/pubmed/commentcorrection/6450206-6996582
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pubmed:language |
eng
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pubmed:journal |
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pubmed:citationSubset |
IM
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pubmed:chemical |
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pubmed:status |
MEDLINE
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pubmed:month |
Jan
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pubmed:issn |
0021-9258
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pubmed:author |
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pubmed:issnType |
Print
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pubmed:day |
25
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pubmed:volume |
256
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
575-8
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pubmed:dateRevised |
2011-9-26
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pubmed:meshHeading |
pubmed-meshheading:6450206-Actins,
pubmed-meshheading:6450206-Actomyosin,
pubmed-meshheading:6450206-Adenosine Triphosphatases,
pubmed-meshheading:6450206-Animals,
pubmed-meshheading:6450206-Calcium,
pubmed-meshheading:6450206-Kinetics,
pubmed-meshheading:6450206-Macromolecular Substances,
pubmed-meshheading:6450206-Molecular Weight,
pubmed-meshheading:6450206-Muscle Proteins,
pubmed-meshheading:6450206-Muscles,
pubmed-meshheading:6450206-Myosins,
pubmed-meshheading:6450206-Protein Binding,
pubmed-meshheading:6450206-Rabbits,
pubmed-meshheading:6450206-Tropomyosin,
pubmed-meshheading:6450206-Troponin
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pubmed:year |
1981
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pubmed:articleTitle |
Mechanism of action of troponin . tropomyosin. Inhibition of actomyosin ATPase activity without inhibition of myosin binding to actin.
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pubmed:publicationType |
Journal Article
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