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. 1970 Aug 1;56(2):147–167. doi: 10.1085/jgp.56.2.147

Sarcoplasmic Reticulum

IX. The permeability of sarcoplasmic reticulum membranes

P F Duggan 1, A Martonosi 1
PMCID: PMC2225859  PMID: 4247172

Abstract

Fragmented sarcoplasmic reticulum (FSR) membranes isolated from rabbit skeletal muscle are impermeable to inulin-14C (mol wt 5,000), and dextran-14C (mol wt 15,000–90,000) at pH 7.0–9.0, yielding an excluded space of 4–5 µl/mg microsomal protein. In the same pH range urea and sucrose readily penetrate the FSR membrane. EDTA or EGTA (1 mM) increased the permeability of microsomes to inulin-14C or dextran-14C at pH 8–9, parallel with the lowering of the FSR-bound Ca++ content from initial levels of 20 nmoles/mg protein to 1–3 nmoles/mg protein. EGTA was as effective as EDTA, although causing little change in the Mg++ content of FSR. The permeability increase caused by chelating agents results from the combined effects of high pH and cation depletion. As inulin began to penetrate the membrane there was an abrupt fall in the rate of Ca++ uptake and a simultaneous rise in ATPase activity. At 40°C inulin penetration occurred at pH 7.0 with 1 mM EDTA and at pH 9.0 without EDTA, suggesting increased permeability of FSR membranes. This accords with the higher rate of Ca++ release from FSR at temperatures over 30°C. The penetration of microsomal membranes by anions is markedly influenced by charge effects. At low ionic strength and alkaline pH acetate and Cl are partially excluded from microsomes when applied in concentrations not exceeding 1 mM, presumably due to the Donnan effect. Penetration of microsomal water space by acetate and Cl occurs at ionic strengths sufficiently high to minimize charge repulsions.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Abrams A. The release of bound adenosine triphosphatase from isolated bacterial membranes and the properties of the solubilized enzyme. J Biol Chem. 1965 Sep;240(9):3675–3681. [PubMed] [Google Scholar]
  2. Dallner G., Ernster L. Subfractionation and composition of microsomal membranes: a review. J Histochem Cytochem. 1968 Oct;16(10):611–632. doi: 10.1177/16.10.611. [DOI] [PubMed] [Google Scholar]
  3. HASSELBACH W., MAKINOSE M. [The calcium pump of the "relaxing granules" of muscle and its dependence on ATP-splitting]. Biochem Z. 1961;333:518–528. [PubMed] [Google Scholar]
  4. MARTONOSI A., FERETOS R. SARCOPLASMIC RETICULUM. II. CORRELATION BETWEEN ADENOSINE TRIPHOSPHATASE ACTIVITY AND CA++ UPTAKE. J Biol Chem. 1964 Feb;239:659–668. [PubMed] [Google Scholar]
  5. MOLNAR J., LORNAD L. A phosphoryl group acceptor attached to the microsomal fraction of muscle. Arch Biochem Biophys. 1962 Sep;98:356–363. doi: 10.1016/0003-9861(62)90198-4. [DOI] [PubMed] [Google Scholar]
  6. Makinose M., Hasselbach W. Der Einfluss von Oxalat auf den Calcium-Transport isolierter Vesikel des sarkoplasmatischen Reticulum. Biochem Z. 1965 Dec 31;343(4):360–382. [PubMed] [Google Scholar]
  7. Martonosi A., Donley J., Halpin R. A. Sarcoplasmic reticulum. 3. The role of phospholipids in the adenosine triphosphatase activity and Ca++ transport. J Biol Chem. 1968 Jan 10;243(1):61–70. [PubMed] [Google Scholar]
  8. Martonosi A. Sarcoplasmic reticulum. IV. Solubilization of microsomal adenosine triphosphatase. J Biol Chem. 1968 Jan 10;243(1):71–81. [PubMed] [Google Scholar]
  9. Martonosi A. The protein composition of sarcoplasmic reticulum membranes. Biochem Biophys Res Commun. 1969 Sep 10;36(6):1039–1044. doi: 10.1016/0006-291x(69)90309-x. [DOI] [PubMed] [Google Scholar]
  10. RAAFLAUB J. Applications of metal buffers and metal indicators in biochemistry. Methods Biochem Anal. 1956;3:301–325. doi: 10.1002/9780470110195.ch10. [DOI] [PubMed] [Google Scholar]
  11. Settlemire C. T., Hunter G. R., Brierley G. P. Ion transport in heart mitochondria. 8. The effect of ethylenediaminetertraacetate on monovalent ion uptake. Biochim Biophys Acta. 1968 Nov 26;162(4):487–499. doi: 10.1016/0005-2728(68)90055-8. [DOI] [PubMed] [Google Scholar]
  12. WILLIS J. B. ANALYSIS OF BIOLOGICAL MATERIALS BY ATOMIC ABSORPTION SPECTROSCOPY. Methods Biochem Anal. 1963;11:1–67. doi: 10.1002/9780470110294.ch1. [DOI] [PubMed] [Google Scholar]

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