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Predicate | Object |
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
21
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pubmed:dateCreated |
1996-7-22
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pubmed:abstractText |
The kinetics of reaction of myosin subfragment-1 (S1) with F-actin have been monitored by the changes in light scattering and in pyrenyl-actin fluorescence at 20 degrees C, pH 7.5, and physiological ionic strength. The association rate constant of S1 to F-actin decreases about 10-fold as the molar ratio of bound S1 increases from 0 to 1. This decrease in k+ is most likely due to the steric hindrance of available binding sites by initially bound S1. The apparent rate constant for association of S1 to bare filaments is 9 microM-1 s-1, a value 1 order of magnitude higher than the one previously estimated from experiments in which S1 was in excess over F-actin. The anticooperative binding kinetics of S1 to F-actin are consistent with the negative cooperativity displayed in the equilibrium binding curves of S1 to pyrenyl-F-actin. Fluorescence titration curves of partially labeled pyrenyl-F-actin by S1 are sigmoidal, consistent with a 4-fold higher affinity of S1 for unlabeled than for labeled action. This conclusion is strengthened by kinetic data of S1 binding to partially labeled F-actin, which exhibit a biphasic behavior due to the slower dissociation of S1 from unlabeled than from labeled actin.
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pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical | |
pubmed:status |
MEDLINE
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pubmed:month |
May
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pubmed:issn |
0021-9258
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:day |
24
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pubmed:volume |
271
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pubmed:owner |
NLM
|
pubmed:authorsComplete |
Y
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pubmed:pagination |
12380-6
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pubmed:dateRevised |
2006-11-15
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pubmed:meshHeading |
pubmed-meshheading:8647841-Actins,
pubmed-meshheading:8647841-Animals,
pubmed-meshheading:8647841-Kinetics,
pubmed-meshheading:8647841-Light,
pubmed-meshheading:8647841-Myosin Subfragments,
pubmed-meshheading:8647841-Protein Binding,
pubmed-meshheading:8647841-Pyrenes,
pubmed-meshheading:8647841-Rabbits,
pubmed-meshheading:8647841-Scattering, Radiation,
pubmed-meshheading:8647841-Temperature
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pubmed:year |
1996
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pubmed:articleTitle |
Kinetics of association of myosin subfragment-1 to unlabeled and pyrenyl-labeled actin.
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pubmed:affiliation |
Laboratoire d'Enzymolgie, CNRS, 91198 Gif-sur-Yvette, France.
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pubmed:publicationType |
Journal Article,
Research Support, Non-U.S. Gov't
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