title: Electron transfer across the chromaffin granule membrane.
abstract: Membrane vesicles (ghosts) containing ascorbic acid were prepared from bovine chromaffin granules. When ferricyanide or ferricytochrome c were added to the external medium, a membrane potential (interior positive) developed across the ghost membrane. This membrane potential could not be elicited from ascorbate-free ghosts or by ferrocyanide added instead of ferricyanide. These results indicate that the chromaffin-granule membrane has a transmembrane electron carrier with a midpoint potential between that of ascorbate (+85 mV) and that of cytochrome c (+255 mV). The most likely candidate is cytochrome b-561 (+140 mV).
mesh_terms: D000313:Adrenal Medulla / Q000378:metabolism*; D000818:Animals; D001205:Ascorbic Acid / Q000494:pharmacology; D002259:Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone / Q000494:pharmacology; D002417:Cattle; D002837:Chromaffin Granules / Q000378:metabolism*; D002838:Chromaffin System / Q000378:metabolism*; D003574:Cytochrome c Group / Q000378:metabolism; D004579:Electron Transport / Q000187:drug effects; D007425:Intracellular Membranes / Q000187:drug effects / Q000378:metabolism*; D007700:Kinetics; D008564:Membrane Potentials; D013050:Spectrometry, Fluorescence
chemical_list: D003574:Cytochrome c Group; D002259:Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone; D001205:Ascorbic Acid