Surface potential changes of mitoplasts in the presence of pyridoxal phosphate modified cytochromes c.
1. The addition of native cytochrome c to mitoplasts leads to a decrease of surface potential of the mitoplast membrane. However the surface potential is slightly decreased (approximately 3 mV) when PLP(Lys 86)-cytochrome c and PLP(Lys 79)-cytochrome c were added. 2. The native and PLP-modified cytochromes c do not influence the order parameters S and isotropic constant a when both spin probe I and probe II were used. It is shown that cytochrome c binding to the membrane does not affect the hydrophobic intermembrane area as well as the lipid arrangements of the mitoplast membrane. 3. At low ionic strength there was observed a significant difference in the membrane potential when PLP-cytochromes c were added to the mitoplasts. 4. At high ionic strength the addition of native or PLP-modified cytochromes c does not change the membrane potential.
Dancheva
K I
KI
Department of Chemistry and Biochemistry, Medical Academy, Sofia, Bulgaria.
Mitovska
M I
MI
Ianakiova
Z K
ZK
Panacenko
O M
OM
Azizova
O A
OA
D003574:Cytochrome c Group / Q000378:metabolism*; D004578:Electron Spin Resonance Spectroscopy; D066298:In Vitro Techniques; D007700:Kinetics; D008563:Membrane Lipids / Q000378:metabolism; D008564:Membrane Potentials; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism*; D009994:Osmolar Concentration; D011732:Pyridoxal Phosphate / Q000494:pharmacology; D013113:Spin Labels; D013367:Submitochondrial Particles / Q000187:drug effects / Q000378:metabolism
D003574:Cytochrome c Group; D008563:Membrane Lipids; D013113:Spin Labels; D011732:Pyridoxal Phosphate