Linked Life Data

2528376

Source:http://linkedlifedata.com/resource/pubmed/id/2528376

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
14
pubmed:dateCreated
1989-10-26
pubmed:abstractText
The equilibrium and dynamics of the interaction between actin, myosin subfragment 1 (S1), and ADP have been investigated by using actin which has been covalently labeled at Cys-374 with a pyrene group. The results are consistent with actin binding to S1.ADP (M.D) in a two-step reaction, A + M.D K1 equilibrium A-M.D K2 equilibrium A.M.D, in which the pyrene fluorescence only monitors the second step. In this model, K1 = 2.3 X 10(4) M-1 (k+1 = 4.6 X 10(4) M-1 s-1) and K2 = 10 (k+2 less than or equal to 4 s-1); i.e., both steps are relatively slow compared to the maximum turnover of the ATPase reaction. ADP dissociates from both M.D and A-M.D at 2 s-1 and from A.M.D at greater than or equal to 500 s-1; therefore, actin only accelerates the release of product from the A.M.D state. This model is consistent with the actomyosin ATPase model proposed by Geeves et al. [(1984) J. Muscle Res. Cell Motil. 5, 351]. The results suggest that A-M.D cannot break down at a rate greater than 4 s-1 by dissociation of ADP, by dissociation of actin, or by isomerizing to A.M.D. It is therefore unlikely to be significantly occupied in a rapidly contracting muscle, but it may have a role in a muscle contracting against a load where the ATPase rate is markedly inhibited. Under these conditions, this complex may have a role in maintaining tension with a low ATP turnover rate.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
11
pubmed:volume
28
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
5864-71
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed:year
1989
pubmed:articleTitle
Dynamic interaction between actin and myosin subfragment 1 in the presence of ADP.
pubmed:affiliation
Department of Biochemistry, School of Medical Sciences, University of Bristol, U.K.
pubmed:publicationType
Journal Article, In Vitro