Evidence that trypsin digestion exposes a channel in the sarcoplasmic reticulum membrane

K. C. Toogood, B. Folsom, T. Topping, H. McCutchan, M. J. Dolejsi, S. Johns, G. Stuart, A. K. Dunker

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2 Scopus citations

Abstract

We present evidence that proteolytic digestion of sarcoplasmic reticulum membranes with trypsin exposes an ion-ophore that is capable of translocating calcium across the membrane of preloaded vesicles. Net transport of calcium appears to stop when the chemical potential of the ion on both sides of the membrane is equal. The temperature coefficient of steady-state leakage suggests that the ionophore is of the channel or pore type. We suggest that tryptic digestion exposes a channel in sarcoplasmic reticulum membranes through which calcium, and perhaps other ions as well, can diffuse down concentration gradients.

Original languageEnglish (US)
Pages (from-to)49-75
Number of pages27
JournalMolecular Membrane Biology
Volume5
Issue number1
DOIs
StatePublished - Jan 1 1983

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Keywords

  • Calcium efflux
  • Sarcoplasmic ReticulumIonop-hore

ASJC Scopus subject areas

  • Molecular Biology
  • Cell Biology

Cite this

Toogood, K. C., Folsom, B., Topping, T., McCutchan, H., Dolejsi, M. J., Johns, S., Stuart, G., & Dunker, A. K. (1983). Evidence that trypsin digestion exposes a channel in the sarcoplasmic reticulum membrane. Molecular Membrane Biology, 5(1), 49-75. https://doi.org/10.3109/09687688309149633