Permeation of Neutral Molecules through Calcium Channel in Sareoplasmic Reticulum Vesicles

Permeation of neutral molecules as well as Ca2+ through the Ca2+ channel in sarcoplasmic reticulum vesicles has been studied by the tracer and/or by the light scattering methods. In the absence of KCl, the Ca2+ channel was found not to be able to pass neutral molecules such as glucose, xylose, and g...

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Bibliographic Details
Published in:Journal of biochemistry (Tokyo) 1992-08, Vol.112 (2), p.197-203
Main Authors: Kasai, Michiki, Kawasaki, Takashi, Yamamoto, Kouki
Format: Article
Language:English
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Summary:Permeation of neutral molecules as well as Ca2+ through the Ca2+ channel in sarcoplasmic reticulum vesicles has been studied by the tracer and/or by the light scattering methods. In the absence of KCl, the Ca2+ channel was found not to be able to pass neutral molecules such as glucose, xylose, and glycine under the condition that the channel was open, although the channel could pass Ca2+. On the other hand, submolar concentrations of KCl made the channel become permeable to neutral molecules as well as Ca2+. Since the effect of KC1 could be replaced by NaCl and KNO3, but not by sucrose and glucose, this effect of KC1 is considered to be due to ionic strength and not to osmotic pressure. These results suggest that low ionic strength transforms the Ca2+ channel protein in such a manner as to block the permeation of neutral molecules without modifying the gating mechanism of the channel.
ISSN:0021-924X
DOI:10.1093/oxfordjournals.jbchem.a123877