Linked Life Data

3408729

Source:http://linkedlifedata.com/resource/pubmed/id/3408729

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
10
pubmed:dateCreated
1988-10-11
pubmed:abstractText
Rabbit skeletal muscle G-actin has been treated to obtain ADP, 1,N6-ethenoadenosine diphosphate (epsilon-ADP), or 1,N6-ethenoadenosine triphosphate (epsilon-ATP) at the nucleotide binding site and either Mg2+ or Ca2+ at high- and moderate-affinity metal binding sites. Apparent rates or rate constants for the displacement of the actin-bound nucleotides by epsilon-ATP or ATP have been obtained by stopped-flow measurements at pH 8 and 20 degrees C of the fluorescence difference between bound and free epsilon-ATP or epsilon-ADP. In the presence of Ca2+, displacement of ADP by epsilon-ATP or epsilon-ADP by ATP is a biphasic process, but in the presence of low (less than 10 microM) Mg2+ concentrations, it is a slow first-order process. At high levels of Mg2+ (greater than 50 microM), low ADP concentrations displace epsilon-ATP from G-actin as a consequence of Mg2+ binding to moderate-affinity sites on the actin. Displacement of epsilon-ATP by ATP in the presence of either Ca2+ or Mg2+ is slow at low ATP concentrations, but the rate is increased by high ATP concentrations. Using ethylene glycol bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid, we find that nucleotide exchange is affected differently by the removal of Ca2+ from the high-affinity site compared to Ca2+ removal from moderate-affinity sites. A mechanism for the displacement reaction is proposed in which there are two forms of an actin-ADP complex and metal binding influences the ratio of these forms as well as the binding of ATP.(ABSTRACT TRUNCATED AT 250 WORDS)
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
17
pubmed:volume
27
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
3812-20
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1988
pubmed:articleTitle
Mechanism for nucleotide exchange in monomeric actin.
pubmed:affiliation
Department of Biological Chemistry, Washington University School of Medicine, St. Louis, Missouri 63110.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.