PMID: 39648Aug 1, 1979

Light-induced conductivity changes in purple membrane suspensions

Biophysics of Structure and Mechanism
M A SlifkinS R Caplan

Abstract

Small light-induced changes in the conductivity of light-adapted purple membrane suspended in strong electrolyte solutions were detected. The method used involved modulated light and a phase sensitive detector and it allowed us to detect accurately changes as small as 0.0001% in the conductivity of the suspension. The light-induced conductivity changes turned out to be composed of at least two different event: a small fast increase in conductivity (tau approximately 2 ms) followed by a slower and larger decrease in this parameter (tau = 70 ms-80 ms). The effects of pH and temperature on these changes were studied. Both events reached maximal values around neutral pH and approached zero at both high and low pH's. Heating the suspension decreased the photoconductivity change and Arrhenius plots of the data showed breaks around 31 degrees C. It is suggested that the conductivity changes reflect changes in the surface charge of the membrane and can be used to follow the kinetics of the conformational changes occurring in the system.

References

Sep 21, 1976·Biochimica Et Biophysica Acta·J K Lanyi, K Hilliker
May 30, 1975·Biophysics of Structure and Mechanism·N Dencher, M Wilms
Mar 14, 1978·Biochimica Et Biophysica Acta·W StoeckeniusR A Bogomolni
Dec 22, 1976·Biophysics of Structure and Mechanism·R KorensteinS R Caplan
Apr 1, 1974·Proceedings of the National Academy of Sciences of the United States of America·A Danon, W Stoeckenius
Aug 17, 1973·European Journal of Biochemistry·D Oesterhelt, B Hess
Oct 1, 1968·The Journal of Physiology·G Falk, P Fatt
Nov 1, 1963·The Journal of General Physiology·R HARA

Citations

Oct 1, 1988·Journal of Bioenergetics and Biomembranes·M A SlifkinS R Caplan

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