Linked Life Data

10412091

Source:http://linkedlifedata.com/resource/pubmed/id/10412091

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1999-9-14
pubmed:abstractText
The concentrations and diffusivity of two isoforms of parvalbumin, IVa and IVb, were measured using quantitative SDS PAGE in single fibers from semitendinosus muscles of the frog Rana temporaria. The concentrations of IVa and IVb were 2.9 +/- 0.3 (SEM) and 4.5 +/- 0.5 g l-1 total fiber volume, respectively. The total concentration of parvalbumin (7.4 +/- 0.8 g l-1 total fiber) corresponds to a cytosolic concentration of 0.9 +/- 0.1 mmol l-1 myoplasmic water. Estimates for the transverse and longitudinal diffusion coefficients for parvalbumin at 4 degrees C were obtained in two ways: (1) by diffusion of parvalbumin out of skinned fibers into droplets of relaxing solution, and (2) by diffusion of parvalbumin between two juxtaposed skinned fibers under oil. The transverse diffusion coefficient obtained using the droplet method was significantly lower than that obtained using juxtaposed fibers, but the longitudinal diffusion coefficients obtained from both methods were similar. The juxtaposed fiber method more accurately approximates parvalbumin diffusion in undisturbed myoplasm because no artificial solutions were used and, upon fiber-to-fiber contact, a potentially confounding oil barrier at the interface rapidly disperses. The juxtaposed fiber method yielded values for transverse (4.27 +/- 0.87 x 10(-7) cm2 s-1) and longitudinal (3.20 +/- 0.74 x 10(-7) cm2 s-1) diffusion coefficients that were not significantly different, suggesting that diffusion of parvalbumin in myoplasm is essentially isotropic. The average diffusion coefficient of frog parvalbumin in myoplasm (3.74 +/- 0.81 x 10(-7) cm2 s-1; 4 degrees C) is approximately a third of that estimated for frog parvalbumin diffusing in bulk water into and out of 3% agarose cylinders (10.6 x 10(-7) cm2 s-1; 4 degrees C). The reduced translational mobility of parvalbumin in myoplasm reflects an elevated effective viscosity due to tortuosity and viscous drag imposed by the fixed proteins of the cytomatrix and the numerous diffusible particles of the cytosol.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0142-4319
pubmed:author
pubmed:issnType
Print
pubmed:volume
20
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
199-209
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed:year
1999
pubmed:articleTitle
Parvalbumin concentration and diffusion coefficient in frog myoplasm.
pubmed:affiliation
Department of Molecular Physiology and Biophysics, University of Vermont, Burlington 05405, USA. maughan@salus.uvm.edu
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.