Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
21
pubmed:dateCreated
1996-7-22
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.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
24
pubmed:volume
271
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
12380-6
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1996
pubmed:articleTitle
Kinetics of association of myosin subfragment-1 to unlabeled and pyrenyl-labeled actin.
pubmed:affiliation
Laboratoire d'Enzymolgie, CNRS, 91198 Gif-sur-Yvette, France.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't