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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
15
pubmed:dateCreated
1976-10-29
pubmed:abstractText
A single cycle of adenosine 5'-triphosphate (ATP) hydrolysis by a complex of actin and myosin subfragment one (acto-S-1) was studied in a stopped-flow apparatus at low temperature and low ionic strength, using light scattering to monitor the interaction of S-1 with actin and fluorescence to detect the formation of fluorescent intermediates. Our results show that the addition of a stoichiometric concentration of ATP to the acto-S-1 causes a cycle consisting of first, a rapid dissociation of the S-1 from actin by ATP; second, a slower fluorescence change in the S-1 that may be related to the initial phosphate burst; and third, a much slower rate limiting recombination of the S-1 with actin. This latter step equals the acto-S-1 steady-state adenosine 5'-triphosphatase (ATPase) rate at both low and high actin concentrations, and like the steady-state ATPase levels off at a V max of 0.9s-1 at high actin concentration. Therefore, the release of adenosine 5'-diphosphate and inorganic phosphate is not the rate-limiting step in the acto-S-1 ATPase. Rather, a slow first-order step corresponding to the previously postulated transition from the refractory to the nonrefractory state precedes the rebinding of the S-1 to the actin during each cycle of ATP hydrolysis.
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
27
pubmed:volume
15
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
3244-53
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed:year
1976
pubmed:articleTitle
Pre-steady-state kinetic evidence for a cyclic interaction of myosin subfragment one with actin during the hydrolysis of adenosine 5'-triphosphate.
pubmed:publicationType
Journal Article