Abstract
Recent evidence has indicated that potassium ion movement through
sarcoplasmic reticulum (SR) K$^+$ channels is an important countercurrent
for Ca$^2+$ release from SR. We used Chaps-solubilized SR vesicles
and sucrose density gradient centrifugation to identify components
of the canine cardiac SR K$^+$ channel. To overcome the difficulty
of the absence of a high-affinity specific ligand, we have successfully
applied the planar lipid bilayer reconstitution technique to identify
and functionally assay for the solubilized SR K$^+$ channel.
We found that Chaps solubilization of the channel did not change
the protein's functional properties. The cardiac SR K$^+$ channel
sediments as a 15-20S protein complex. A polypeptide of Mr approximately
80 kDa was found to specifically comigrate with the 15-20S gradient
fractions and might be a major constituent of the cardiac SR K$^+$
channel.
- 1936241
- animals,
- centrifugation,
- channels,
- density
- dogs,
- electrophoresis,
- gel,
- gov't,
- gradient,
- myocardium,
- p.h.s.,
- polyacrylamide
- potassium
- research
- reticulum,
- sarcoplasmic
- solubility,
- support,
- u.s.
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