Medical College of Wisconsin
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Transport of spin-labeled tetracycline across model and biological membranes. Life Sci 1993;52(12):1071-8

Date

01/01/1993

Pubmed ID

8383269

DOI

10.1016/0024-3205(93)90200-m

Abstract

Electron spin resonance spectra of spin labeled tetracycline (TC-SL) do not show any recognizable partitioning into a lipid bilayer or bulk hydrocarbon solvent, paraffin oil. TC-SL, however, penetrates through the model and biological membranes. It is shown that the rate of permeation depends on membrane composition and increases with temperature. In fluid phase, the rate is greater for saturated dimyristoylphosphatidylcholine than for unsaturated egg yolk phosphatidylcholine membranes. Cholesterol significantly decreases the rate, 30 mol% cholesterol decreases the rate of TC-SL permeation across egg yolk phosphatidylcholine bilayer 8 times at 37 degrees C. The rate of permeation of TC-SL across model membranes is much smaller than the rate for TEMPONE--a compound which slightly partitions into lipid bilayer, and much greater than the rate for TEMPO--choline-a positively charged compound. After addition to the suspension of Ehrlich's ascites tumor cells, the TC-SL is reduced to a non-paramagnetic form. Reduction rate is independent of oxygen concentrations, which led us to suggest that the permeation of TC-SL across the cell plasma membrane is the limiting step of reduction reaction.

Author List

Pezeshk A, Pezeshk V, Firlej A, Wojas J, Subczynski WK

Author

Witold K. Subczynski PhD Professor in the Biophysics department at Medical College of Wisconsin




MESH terms used to index this publication - Major topics in bold

Animals
Carcinoma, Ehrlich Tumor
Electron Spin Resonance Spectroscopy
Kinetics
Liposomes
Mice
Models, Biological
Permeability
Spin Labels
Tetracycline