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Membrane surface potential of Spiroplasma floricola
Author(s) -
Schummer Ulrich,
Schiefer Hans Gerd
Publication year - 1988
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(88)80051-6
Subject(s) - membrane , chemistry , biophysics , phosphate , membrane potential , fluorescence , ion , analytical chemistry (journal) , biochemistry , chromatography , biology , optics , organic chemistry , physics
Anionic charges, cytochemically identified as lipid phosphate groups, cover the outer membrane surface of Spiroplasma floricola . They induce a negative membrane surface potential which affects the distribution of ions, including protons. Accordingly, the pH at the interface differs from the bulk pH. By using the fluorescent lipoid pH indicator 4‐heptadecyl‐7‐ hydroxycoumarin, the pH at the membrane surface was determined. From the difference of the bulk and the interfacial pH the membrane surface potential of S. floricola was calculated to be ϕ = − 118 mV.