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Predicate | Object |
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
24
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pubmed:dateCreated |
1982-3-13
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pubmed:abstractText |
Studies of the cardiac myosin fragment 1 concentration dependence of the rate constants for adenosine 5'-triphosphate (ATP) binding and steady-state hydrolysis reveal that the observed rate constants are remarkably dependent on the protein concentration. The kinetics for ATP binding are biphasic, and both the fast- and slow-phase rate constants and the respective fractions of fast and slow material vary as a function of protein concentration. Two different types of kinetic experiments were conducted, one in which the ATP concentration was fixed but the subfragment 1 concentration was varied and another for which the ATP/subfragment 1 ratio was fixed but both concentrations were varied. The results of these two experiments on cardiac subfragment 1 are consistent with an ATP-dependent reversible aggregation. Light-scattering experiments confirm the presence of this aggregation and the ATP dependence. Similar studies on rabbit skeletal subfragment 1 give monophasic, protein-independent kinetics consistent with a monomeric species in solution. a simple monomer--dimer mechanism can account for the cardiac subfragment 1 kinetic results when changes in tryptophan fluorescence are used. However, the light-scattering results show that cardiac myosin subfragment 1 undergoes multiple reversible molecular weight changes in solution and may be tetrameric at high concentrations.
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pubmed:grant | |
pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical |
http://linkedlifedata.com/resource/pubmed/chemical/Adenosine Triphosphate,
http://linkedlifedata.com/resource/pubmed/chemical/Macromolecular Substances,
http://linkedlifedata.com/resource/pubmed/chemical/Myosin Subfragments,
http://linkedlifedata.com/resource/pubmed/chemical/Myosins,
http://linkedlifedata.com/resource/pubmed/chemical/Peptide Fragments
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pubmed:status |
MEDLINE
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pubmed:month |
Nov
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pubmed:issn |
0006-2960
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:day |
24
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pubmed:volume |
20
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
6760-7
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pubmed:dateRevised |
2009-11-19
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pubmed:meshHeading |
pubmed-meshheading:7317351-Adenosine Triphosphate,
pubmed-meshheading:7317351-Animals,
pubmed-meshheading:7317351-Cattle,
pubmed-meshheading:7317351-Kinetics,
pubmed-meshheading:7317351-Macromolecular Substances,
pubmed-meshheading:7317351-Molecular Weight,
pubmed-meshheading:7317351-Muscles,
pubmed-meshheading:7317351-Myocardium,
pubmed-meshheading:7317351-Myosin Subfragments,
pubmed-meshheading:7317351-Myosins,
pubmed-meshheading:7317351-Peptide Fragments,
pubmed-meshheading:7317351-Rabbits,
pubmed-meshheading:7317351-Spectrometry, Fluorescence
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pubmed:year |
1981
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pubmed:articleTitle |
Aggregation-linked kinetic heterogeneity in bovine cardiac myosin subfragment 1.
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pubmed:publicationType |
Journal Article,
Research Support, U.S. Gov't, P.H.S.,
Research Support, Non-U.S. Gov't
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