Fatty acid flip-flop and proton transport determined by short-circuit current in planar bilayers
The effect of palmitic acid (PA) and oleic acid (OA) on electrical parameters of planar membranes was studied. We found a substantial difference between the effects of PA and OA on proton transfer. PA induced a small increase in conductance, requiring a new technique for estimating proton-mediated c...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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Elsevier
2005-02-01
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| Series: | Journal of Lipid Research |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S0022227520340578 |
| _version_ | 1818739289223069696 |
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| author | Kellen Brunaldi Manoel Arcisio Miranda Fernando Abdulkader Rui Curi Joaquim Procopio |
| author_facet | Kellen Brunaldi Manoel Arcisio Miranda Fernando Abdulkader Rui Curi Joaquim Procopio |
| author_sort | Kellen Brunaldi |
| collection | DOAJ |
| description | The effect of palmitic acid (PA) and oleic acid (OA) on electrical parameters of planar membranes was studied. We found a substantial difference between the effects of PA and OA on proton transfer. PA induced a small increase in conductance, requiring a new technique for estimating proton-mediated currents across low-conductance planar bilayers in which an electrometer is used to measure the transmembrane current under virtual short circuit (SCC). Open-circuit voltage and SCC were used to determine proton and leak conductances. OA caused a marked increase in membrane conductance, allowing the use of a voltage-clamp technique.From SCC data, we were able to estimate the flip-flop rate constants for palmitate (1 × 10−6 s−1) and oleate (49 × 10−6 s−1) anions. Cholesterol, included in the membrane-forming solution, decreased importantly the leak conductance both in membranes unmodified by FA and in membranes modified by PA added to the bath. |
| first_indexed | 2024-12-18T01:22:28Z |
| format | Article |
| id | doaj.art-3470e183a5f0407b82686eee18551fd1 |
| institution | Directory Open Access Journal |
| issn | 0022-2275 |
| language | English |
| last_indexed | 2024-12-18T01:22:28Z |
| publishDate | 2005-02-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Journal of Lipid Research |
| spelling | doaj.art-3470e183a5f0407b82686eee18551fd12022-12-21T21:25:47ZengElsevierJournal of Lipid Research0022-22752005-02-01462245251Fatty acid flip-flop and proton transport determined by short-circuit current in planar bilayersKellen Brunaldi0Manoel Arcisio Miranda1Fernando Abdulkader2Rui Curi3Joaquim Procopio4Department of Physiology and Biophysics, Biomedical Sciences Institute, University of São Paulo, São Paulo, Brazil 05435040Department of Physiology and Biophysics, Biomedical Sciences Institute, University of São Paulo, São Paulo, Brazil 05435040Department of Physiology and Biophysics, Biomedical Sciences Institute, University of São Paulo, São Paulo, Brazil 05435040Department of Physiology and Biophysics, Biomedical Sciences Institute, University of São Paulo, São Paulo, Brazil 05435040Department of Physiology and Biophysics, Biomedical Sciences Institute, University of São Paulo, São Paulo, Brazil 05435040The effect of palmitic acid (PA) and oleic acid (OA) on electrical parameters of planar membranes was studied. We found a substantial difference between the effects of PA and OA on proton transfer. PA induced a small increase in conductance, requiring a new technique for estimating proton-mediated currents across low-conductance planar bilayers in which an electrometer is used to measure the transmembrane current under virtual short circuit (SCC). Open-circuit voltage and SCC were used to determine proton and leak conductances. OA caused a marked increase in membrane conductance, allowing the use of a voltage-clamp technique.From SCC data, we were able to estimate the flip-flop rate constants for palmitate (1 × 10−6 s−1) and oleate (49 × 10−6 s−1) anions. Cholesterol, included in the membrane-forming solution, decreased importantly the leak conductance both in membranes unmodified by FA and in membranes modified by PA added to the bath.http://www.sciencedirect.com/science/article/pii/S0022227520340578lipid membranescholesterolelectrometer |
| spellingShingle | Kellen Brunaldi Manoel Arcisio Miranda Fernando Abdulkader Rui Curi Joaquim Procopio Fatty acid flip-flop and proton transport determined by short-circuit current in planar bilayers Journal of Lipid Research lipid membranes cholesterol electrometer |
| title | Fatty acid flip-flop and proton transport determined by short-circuit current in planar bilayers |
| title_full | Fatty acid flip-flop and proton transport determined by short-circuit current in planar bilayers |
| title_fullStr | Fatty acid flip-flop and proton transport determined by short-circuit current in planar bilayers |
| title_full_unstemmed | Fatty acid flip-flop and proton transport determined by short-circuit current in planar bilayers |
| title_short | Fatty acid flip-flop and proton transport determined by short-circuit current in planar bilayers |
| title_sort | fatty acid flip flop and proton transport determined by short circuit current in planar bilayers |
| topic | lipid membranes cholesterol electrometer |
| url | http://www.sciencedirect.com/science/article/pii/S0022227520340578 |
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